Advances in Posttraumatic Stress Disorder (PTSD): A Primer

Advances in Posttraumatic Stress Disorder (PTSD): A Primer

• 1.    https://psychscenehub.com/psychinsights/advances-posttraumatic-stress-disorder-ptsd/ sanil.rege@gmail.com 238 min read Advances in Understanding Posttraumatic Stress Disorder (PTSD): A Comprehensive Review of Pathophysiology, Diagnosis, and Management Posted on: October 30, 2024 Last Updated: October 31, 2024 Time to read: 111-150 minute(s) 1200 This article explores the latest advances in understanding Posttraumatic Stress Disorder (PTSD), highlighting its complexity as a heterogeneous condition marked by neurocircuit alterations affecting emotion, memory, and arousal regulation. It provides a comprehensive overview of the disorder’s pathophysiology, diagnostic complexities, and evidence-based management, emphasising the importance of personalised, phase-specific interventions. PTSD arises from the direct or indirect experience of a life-threatening or distressing event, often leaving an enduring psychological impact marked by physical, cognitive, emotional, and behavioural changes.

• 2. These traumatic events trigger intense feelings of fear, helplessness, and horror, setting the stage for the development of chronic symptoms. Classified in the DSM-5 as a trauma and stressor-related disorder, PTSD is characterised by intrusive memories, hypervigilance, emotional numbness, and efforts to avoid reminders of the trauma. Symptoms often persist beyond the original context, reflecting a failure to update safety signals and perpetuating a sense of danger and unpredictability. Understanding the neurobiology of PTSD is crucial for exploring how trauma imprints on the brain and behaviour. Across different cultures and historical periods, similar symptom patterns such as flashbacks, nightmares, and heightened startle responses indicate shared neurobiological foundations. Research into PTSD’s development reveals a complex interaction of pre-trauma vulnerabilities, immediate peritraumatic responses, and posttraumatic factors that influence both chronicity and recovery. By understanding these mechanisms-spanning molecular pathways, neurocircuit disruptions, and changes in neurocognitive, emotional, and interpersonal processes, clinicians can better predict, diagnose, and treat this disorder. Psychological trauma can be classified into 4 clusters of symptoms. These include: Intrusion symptoms– Flashbacks, nightmares, and intrusive thoughts Avoidance – Avoidance of stimuli associated with trauma Negative Alterations in Cognitions and Mood associated with the traumatic event (s) – difficulty recalling important aspects of trauma, emotional detachment, etc. Hyperarousal – Hypervigilance, Insomnia, agitation, irritability, impulsivity, and anger For some, however, the syndrome persists, and this is termed post-traumatic stress disorder (PTSD).

• 3. A PTSD diagnosis was originally considered a normal response to an extreme situation; however, the presence of symptoms for an extended period of time beyond one month is indicative of an abnormal adaptation in the brain. We covered Complex PTSD in a separate article. Know how to diagnose PTSD accurately Learn the neurobiology, features, symptoms, and treatment options for PTSD in our comprehensive course. Join Academy by Psych Scene to get access and earn CME/CPD points. PREVALENCE OF PTSD The prevalence of PTSD varies across countries. It occurs in 5-10% of the population and has a 2:1 female-to-male ratio. The gender bias may be a result of a combination of a greater propensity to lifetime violence exposure and genetic vulnerability (variation in the ADCYAP1R1 (pituitary receptor) gene). [Yehuda et al., 2015] In military populations, the risk is more significant. In a study of 69,000 adults globally, 70% experienced at least one traumatic event, and 30.5% faced four or more events. [Benjet et al., 2016] Most trauma survivors do not develop PTSD; they experience transient symptoms, which may intensify at specific times (e.g., anniversaries), but generally maintain good functioning. Trauma can lead to other psychiatric disorders, including major depression and substance misuse, not just PTSD. The National Comorbidity Survey estimated lifetime PTSD prevalence at 6.8% among U.S. adults, with current prevalence at 3.5%. [Kessler et al., 2005] PTSD prevalence is higher among women than men, with lifetime rates of 9.7% in women versus 3.6% in men; past-year rates are 5.2% in women versus 1.8% in men. [Shalev et al., 2024]

• 4. Among Vietnam veterans, lifetime PTSD prevalence was 30.9% for men and 26.9% for women; 15–18 years post-war, current rates were 15.2% for men and 8.1% for women. Longitudinal studies of Vietnam veterans found that 4.5% had current PTSD 40 years after the war, with 17% having lifetime war-zone PTSD. [Marmar et al., 2015] Symptoms of PTSD generally decrease within a year post-trauma, with initial symptom rates dropping significantly over time, as seen in rape and nonsexual assault survivors. Median PTSD remission time is 36 months for those who seek help and 64 months for those who do not; one-third of cases remain chronic. [Shalev et al., 2024] Delayed-onset PTSD is rare; it often involves worsening of existing symptoms or delayed help-seeking, as seen in studies of combat veterans. [Shalev et al., 2024] RISK FACTORS FOR PTSD Demographic Factors [Shalev et al., 2024] Female gender – twice as likely to develop PTSD Younger age at trauma Race: In the U.S., African Americans, Latino Americans, and Native Americans exhibit the highest rates of PTSD, while Asian Americans have the lowest prevalence. [Asnaani & Hall-Clark, 2017]. Indigenous Australians face a higher likelihood of experiencing traumatic events and developing PTSD compared to other Australians. [Nasir et al., 2021] Lower education levels Personal History Previous trauma (both adult and childhood) Psychological adjustment issues Family history of psychopathology. Attachment style and personality traits like neuroticism and introversion Trauma Severity Higher trauma severity, perceived life threat, emotional distress, and dissociation during trauma.

• 5. Social Support Lack of social support following trauma. Additional Stressors Experiencing further life stressors after the traumatic event raises PTSD risk Combat-Related Factors For combat-related PTSD, risk factors include lower education, non-officer status, longer deployments, adverse life events, and pre-existing psychological issues. Interpersonal Violence Exposure to interpersonal violence or multiple traumatic events significantly elevates the risk of PTSD. Amygdala Hyperresponsivity Heightened amygdala activation in response to ambiguous facial expressions (e.g., surprised or neutral) may serve as a familial vulnerability marker for PTSD. [Hinojosa et al., 2022] Genetic Vulnerability: [Shalev et al., 2024] Approximately 30–40% of PTSD risk is heritable, with environmental factors like trauma type and individual differences in fear regulation playing critical roles. [Ressler et al., 2022] Variants in genes such as FKBP5, PACAP1, COMT, DRD2, and RGS2 are linked to PTSD risk, particularly in those with a history of childhood trauma. [Nievergelt et al., 2018] The s/s genotype of the serotonin transporter gene (5-HTTLPR) combined with childhood adversity increases PTSD risk. [Uher et al., 2011] Single-nucleotide polymorphism on chromosome 4 and an estrogen response element on ADCYAP1R1 are implicated.

• 6. Specific Gene Associations: CRFR1 and PAC1R: Variations in genes encoding CRFR1 and PAC1R are linked to increased hyperarousal, higher PTSD symptoms, and heightened physiological responses to stress. Both genes are prominently expressed in PTSD-related brain areas (amygdala, bed nucleus of the stria terminalis, medial prefrontal cortex), influencing fear and hyperarousal differently in men and women. [Ressler et al., 2022] FKBP5 Pathway: FKBP5, a key regulator of the cellular glucocorticoid response, is associated with PTSD risk, especially among those with childhood trauma exposure. It influences PTSD symptom type and severity, neural activity, and startle responses, with increased FKBP5 expression found in the brains of individuals with PTSD. [Ressler et al., 2022] Epigenetic Changes: [Shalev et al., 2024] In PTSD, epigenetic modifications adjust gene promoter activity, altering gene expression without changing DNA sequence. Reduced methylation of the glucocorticoid receptor gene suggests altered stress regulation. Unique DNA methylation patterns, with unmethylated immune-related genes and increased overall methylation. Changes in de novo methylation genes, like DNMT3B and 3L, indicate adaptive epigenetic shifts. In rodents, trauma decreases BDNF expression via reduced histone acetylation, while fear extinction increases acetylation, promoting recovery. Successful PTSD treatment correlates with changes in DNA methylation at specific regions, showing that epigenetic shifts can be reversed. [Vinkers et al., 2021], [Bishop et al., 2018], [Yehuda et al., 2013]

• 7. Epigenetic Mechanisms in Psychiatric Disorders – Major Depression, Psychosis and Addiction Trauma outcomes vary across individuals, and this appears to be dependent on genetic susceptibility factors, history of prior psychological trauma, or an additional physical injury at the time of the traumatic event, such as traumatic brain injury (TBI). DIAGNOSTIC CRITERIA FOR PTSD The Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5) recognises several criteria for a PTSD diagnosis. The PTSD criteria are as follows: 1.Exposure to stressor The individual was either directly or indirectly (witnessing, learning, or exposure to aversive details) exposed to trauma. 2. Intrusion symptoms (one or more required) The trauma is persistently re-experienced via recurrent memories, nightmares, flashbacks, psychological distress, or physiological reactivity to traumatic reminders. 3. Persistent avoidance (one or more required) Avoidance of trauma-related stressors: recurrent trauma-related thoughts or environmental reminders such as people, activities, and places that act as visual reminders. 4. Negative alterations in cognition and mood (two or more required) Inability to recall key features, persistent (and often distorted) negative beliefs and expectations about oneself or the world, persistent distorted blame of self or others, persistent negative trauma-related emotions, markedly diminished interest in pretraumatic activities, feeling alienated from others and constricted affect (persistent inability to experience positive emotions). 5. Alterations in arousal and reactivity (two or more required)

• 8. Disturbances to arousal and reactivity that began, or worsened, after the trauma are characterised by aggression, self-destructive or reckless behaviour, hyper-vigilance, exaggerated startle response, and difficulty concentrating or sleeping. 6. Duration More than one month. 7. Functional significance Trauma-related symptoms must cause psychological, social, or functional impairment. Exclusion Trauma-related symptoms cannot be attributed to medications or substance abuse. Click to enlarge. Downloadable with a Hub Pro subscription. The ICD-11 PTSD diagnosis is similar to the DSM-5 but more narrow, focusing on traditional fear circuitry symptoms such as re-experiencing, avoidance, and hypervigilance. [Burback et al., 2024]

• 9. The dissociative subtype of PTSD (PTSD-DT) and Complex PTSD (CPTSD), recently included in the DSM-5 and ICD-11, highlight distinct clinical presentations within PTSD characterised by significant complexity. Both conditions are closely linked to chronic trauma, particularly early childhood trauma and neglect, and are marked by persistent dissociative symptoms. These subsets tend to show a heavier trauma burden and a more severe and prolonged course compared to typical PTSD, with higher rates of suicidal ideation, anxiety, depression, and comorbid BPD. [Burback et al., 2024] We have covered the differences between PTSD, Borderline Personality Disorder (BPD) and CPTSD in this article. UNDERSTANDING THE NEUROBIOLOGY OF FEAR AND ANXIETY: FOUNDATIONS FOR PTSD PATHOPHYSIOLOGY Elucidating the neurobiology of fear and threat processing is essential for understanding the link between trauma and symptoms of PTSD. Fear processing circuits, including the amygdala, hippocampus, and medial prefrontal cortex, are well-studied across species and provide a basis for understanding PTSD’s manifestations. Processes like trauma memory encoding, consolidation, and extinction, critical to PTSD’s development, rely on synaptic plasticity and memory systems. The Neuroscience of Emotions: Clinical Relevance for Understanding Depression, Anxiety, and Addiction THE ROLE OF THE AMYGDALA The amygdala is central to fear processing, acting as a hub for detecting and responding to threatening stimuli. [Li et al., 2023]

• 10. Click to enlarge. Downloadable with a Hub Pro subscription. The amygdala integrates sensory information to generate rapid, often reflexive responses, mediated through connections to the hypothalamus and brainstem structures like the periaqueductal gray (PAG). The PAG orchestrates defensive behaviours such as freezing or fleeing, characteristic responses to acute fear. In contrast, anxiety involves more sustained neural activity, primarily engaging the extended amygdala, which includes the bed nucleus of the stria terminalis (BNST). The BNST has been implicated in processing uncertain or diffuse threats, contributing to anxiety’s prolonged, anticipatory nature. The prefrontal cortex (PFC), particularly the medial PFC (mPFC), modulates fear and anxiety by exerting top-down control over the amygdala and BNST, facilitating threat appraisal and regulatory mechanisms that can suppress or amplify emotional responses.

• 11. Click to enlarge. Downloadable with a Hub Pro subscription. NEUROTRANSMITTER SYSTEMS IN FEAR AND ANXIETY GABA: GABAergic inhibition in the amygdala plays a crucial role in reducing fear responses, while the loss of GABAergic tone is associated with heightened anxiety. [Grogans et al., 2023] Glutamate: The amygdala and its associated structures (e.g., PAG, hypothalamus.) serve as a central defensive system in the mammalian brain against external threats from the environment. Again, the degree of engaging other neural structures might lead to fear, anxiety, phobia, panic, and so on. A useful analogy would be the common ingredients in bread (i.e., flour, salt, water). Other neural structures would be specific ingredients (e.g., yeast, egg, sugar) that can be added to these foundational ingredients to produce different types of bread (e.g., flatbreads, sourdough, cake). Ingredient imbalances may serve as a metaphor for pathological fear, anxiety, and panic. (Kim) from [Grogans et al., 2023] 

• 12. Glutamate, the principal excitatory neurotransmitter, facilitates rapid communication between the amygdala and other regions, driving immediate fear responses and modulating sustained anxiety through BNST activity. [Li et al., 2023] Serotonin: Serotonin has a more nuanced role, with its impact on fear and anxiety being highly context-dependent. [Bocchio et al., 2016] It is involved in both dampening and enhancing threat responses, influenced by the receptor subtype and neural circuit involved. Serotonin modulates amygdala function via 5-HT receptors, impacting fear processing and emotional memory encoding. [Vitalis & Verney, 2018] In the amygdala, 5-HT2A/2C receptors enhance fear conditioning, while 5-HT1A receptors facilitate extinction. Serotonin also modulates the hippocampus and mPFC via volume transmission, maintaining homeostasis. For instance, serotonin’s action in the dorsal raphe nucleus (DR / DRN) can mitigate anxiety, while its role in other pathways may heighten vigilance under perceived threat. [Bocchio et al., 2016] Acetylcholine: Basal forebrain cholinergic signalling, primarily from the nucleus basalis of Meynert (NBM) and the horizontal limb of the diagonal band of Broca (HDB), plays a crucial role in fear regulation within the basolateral amygdala (BLA). These pathways enhance the strength and persistence of fear memories, with NBM projections specifically modulating fear conditioning and extinction through nicotinic receptor activation. [Crimmins et al., 2023] Dopamine (DA)

• 13. Dopamine (DA) serves as a central modulator of both fear extinction and aversive learning, impacting multiple brain circuits involved in anxiety and threat processing. In the amygdala, DA projections to the BLA encode the salience of stimuli, mediating associative learning. [Zafiri & Duvarci, 2022] DA inputs from the ventral tegmental area (VTA) and periaqueductal gray (PAG)/dorsal raphe (DR) target the central amygdala (CEA), with PAG/DR inputs driving associative aversive learning and VTA inputs facilitating fear discrimination. In the mPFC, VTA-derived DA modulates conditioned fear expression and biases behaviour toward aversion, while its role in striatal subregions like the ventral nucleus accumbens (NAc) and tail of the striatum (TS) involves encoding motivational salience and mediating threat avoidance, respectively. DA plays a crucial role in fear extinction by influencing the acquisition and consolidation of extinction memories. Originating from midbrain structures like the VTA and substantia nigra (SN), DA neurons project to the amygdala and mPFC, key regions in fear regulation. DA signalling, particularly through D1-type receptors, enhances the learning and retention of extinction when administered before or after extinction training. Recent findings suggest that fear extinction may engage the brain’s reward circuits, positioning DA as a mediator of fear suppression and an appetitive learning process within the amygdala and mPFC. [Salinas-Hernández & Duvarci, 2021]

• 14. Click to enlarge. Downloadable with a Hub Pro subscription. Noradrenaline (NA): Noradrenaline, released from the locus coeruleus, is integral to the arousal component of fear and anxiety, increasing sensory sensitivity and attention towards potential threats. The locus coeruleus-noradrenaline (LC-NA) system is pivotal in regulating fear learning, memory, and extinction, modulating these processes based on arousal levels. During high stress, LC-NA amplifies amygdala-driven fear learning while dampening prefrontal control, resulting in stronger aversive memories. In contrast, under lower arousal, LC-NA enhances prefrontal inhibition of the amygdala, supporting fear extinction. This relationship follows an “inverted-U” function, where optimal arousal improves learning while extreme arousal disrupts it. [Bierwirth & Stockhorst, 2022] Additionally, NA’s role in the hippocampus, due to dense adrenoceptor expression, facilitates contextual fear memory formation. Interactions between LC, amygdala, and hypothalamus—mediated by corticotropin-releasing hormone (CRF) and NA—further intensify fear conditioning and emotional memory encoding.

• 15. Increased noradrenergic arousal contributes to deficits in fear extinction, underscoring mechanisms critical to PTSD. [Giustino & Maren, 2018] Click to enlarge. Downloadable with a Hub Pro subscription. PHYSIOLOGICAL RESPONSES IN FEAR AND ANXIETY The physiological responses to stress exhibit diverse temporal dynamics, reflecting the complexity of the hypothalamic-pituitary-adrenal (HPA) axis and its broader implications. Fear and anxiety both trigger sympathetic nervous system activation, manifesting as increased heart rate, pupil dilation, and other autonomic changes that prepare the body for immediate action. [Godoy et al., 2018] Cortisol release is central to these responses, but its timing varies. Rapid (Acute) Cortisol Response: Initiated within seconds to minutes, acute cortisol release, part of the immediate stress response, involves activating the sympathetic nervous system, leading to rapid physiological changes (e.g., increased heart rate, pupil dilation). This phase is characterized by the modulation of limbic-cortical circuits, enhancing neural excitability in areas like the amygdala and hippocampus, which are crucial for fear and threat processing. [Joëls et al., 2012]

• 16. Such acute cortisol responses facilitate immediate adaptation and promote the encoding of stressful experiences, aiding in learning and memory formation. [Bains et al., 2015] Delayed (Prolonged) Cortisol Response: Occurs hours after initial stressor exposure and primarily affects synaptic plasticity in limbic-cortical structures. This phase can impair cognitive functions, alter synaptic plasticity (e.g., long-term potentiation and depression), and maintain neural excitability beyond acute responses. These delayed cortisol effects contribute to more sustained HPA activation, typical of anxiety states, and modulate the encoding and consolidation of longer-term memories. [Joëls et al., 2012] Prolonged or chronic stress disrupts these mechanisms, resulting in structural changes like hippocampal atrophy and amygdala hypertrophy, leading to anxiety and cognitive deficits. Early-life stress exerts enduring effects, increasing vulnerability to psychiatric disorders later in life. [Godoy et al., 2018] THE PATHOPHYSIOLOGY OF PTSD The neurobiology of PTSD is complex and involves neuroendocrine, neurochemical and neuroanatomical changes in neural networks. 1. Fear Conditioning and Extinction: Core Circuits The amygdala, hippocampus, and mPFC form the core network for fear conditioning, involving acquisition, consolidation, and extinction of fear responses. [Ressler et al., 2022] Amygdala’s basolateral nucleus processes sensory inputs and links them to aversive stimuli, forming fear memories. These memories consolidate through NMDA receptor activation, BDNF, and calcium-dependent plasticity, leading to structural changes. Overactivity in the amygdala’s central nucleus triggers downstream regions like the hypothalamus, LC, and PAG, driving physiological stress responses, including

• 17. increased heart rate and activation of the HPA axis. In PTSD, amygdala hyperactivity persists due to inadequate inhibition from the mPFC, resulting in heightened responses to conditioned stimuli. Structural MRI studies confirm alterations in these circuits, with reduced hippocampal and medial prefrontal volumes correlating with symptom severity. In PTSD, a decreased PFC volume correlates with symptom severity due to decreased inhibitory control over the amygdalar stress response. 2. Role of the Amygdala in Threat Processing and PTSD Symptoms The amygdala plays a central role in acquiring fear responses and mediating both overconsolidation and extinction failures in PTSD. Heightened amygdala activity persists due to weakened prefrontal inhibition, contributing to hypervigilance, intense physiological responses, and difficulty distinguishing between safe and threatening cues. This contributes to startle responses and persistent reactivity to trauma-related stimuli. [Shalev et al., 2024] Monoaminergic systems, including serotonin, norepinephrine, and dopamine, influence these responses by modulating the consolidation of threat associations, potentially leading to threat overgeneralisation. Structural abnormalities within the amygdala, including increased glutamate transmission and NMDA receptor activity, are linked to pathological memory consolidation and a hyperresponsive reaction to subliminal threats. Structural MRI analysis has revealed pathological damage to the amygdala, which was associated with a hyper-responsive reaction to subliminally threatening cues. [Van Rooij et al., 2015] 3. Medial Prefrontal Cortex and Hippocampal Regulation The mPFC (specifically the vmPFC) regulates fear responses by inhibiting the amygdala and modulating distress. In PTSD, decreased mPFC activity and compromised integrity of the uncinate fasciculus impair this regulatory function, contributing to the persistence of fear and avoidance behaviours. [Shalev et al., 2024] The hippocampus is crucial for encoding fear memories, contextual processing, and regulating amygdala activation. Structural changes, like reduced hippocampal

• 18. volume, are evident in PTSD and may be due to cortisol-induced neurotoxicity, impairing extinction learning. [Blum et al., 2019] Neuroimaging shows that reduced mPFC and hippocampal activation correlate with symptom severity, reflecting deficits in the ability to suppress fear and transition to recognising safety cues. [Hinojosa et al., 2024] 4. Threat and Salience Detection | Emotional Regulation Circuits The amygdala, dorsal anterior cingulate cortex (dACC), and insula are key to detecting and evaluating threat salience. The PFC, in conjunction with the hippocampus, manages emotion regulation by assessing and updating safety cues. In PTSD, overactivity in the amygdala and insula, coupled with reduced PFC activity, impairs the discrimination of safe cues, leading to sustained hyperarousal and reactivity. Decreased frontal cortex and ACC volumes are found in patients with PTSD. 5. Fear-On, Fear-Off, and APPT-On Circuits The amygdala contains three primary circuits associated with different emotional responses. [Ressler et al., 2022] 1. Fear-On circuits: Trigger and sustain fear responses Increase Anxiety Mediated by factors like CRF, PACAP, and TAC2. 2. Fear-Off circuits Inhibit fear responses Fear Extinction Reduce anxiety. 3. APPT-On Circuits: Appetitive (Appetitive) and reward-related responses

• 19. Regulate fear processing. In PTSD, there is often an overactivation of Fear-On circuits and a concurrent suppression of Fear-Off circuits, leading to persistent fear responses. This imbalance underlies many of the anxiety-related symptoms of PTSD, such as hyperarousal and intrusive thoughts. Moreover, dysregulation of APPT-On circuits can contribute to depression-like symptoms, including anhedonia and avolition, which are common comorbid features of PTSD. 6. Executive Control, Memory, and Attention Dysregulation PTSD-associated symptoms, such as impaired concentration and memory, are linked to dysfunctions in the dACC and frontoparietal attentional networks. These networks are responsible for working memory, response inhibition, and performance monitoring. Dysregulated connectivity between these networks and the default mode network (DMN) impedes the ability to disengage from trauma-related stimuli, affecting attention regulation and internal state management. [Jagger-Rickels et al., 2022] 7. Contextual Processing and Appraisal in PTSD The inability to transition from a threat-focused state to recognising safety is a hallmark of PTSD. The vmPFC, hippocampus, and thalamus are central to this process, which relies on adrenergic regulation, especially during sleep. In PTSD, decreased vmPFC activity impairs extinction recall and contextual learning, leading to persistent hypervigilance and difficulties updating safety cues. [Liberzon & Abelson, 2016] Neuroendocrine Aspects in PTSD: 1. Hypothalamic-Pituitary-Adrenal (HPA) Axis Dysregulation [Lawrence & Scofield, 2024]

• 20. The HPA axis is the primary stress-response system, initiating in the hypothalamus with the secretion of corticotropin-releasing hormone (CRH) from paraventricular neurons (PVN). This stimulates the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary, leading to the release of glucocorticoids (e.g., cortisol) from the adrenal cortex. In PTSD, there is altered cortisol signalling due to increased glucocorticoid receptor sensitivity, resulting in enhanced negative feedback and blunted cortisol responses to stress. This leads to reduced cortisol levels during stress exposure, which impairs normal HPA functioning. [Yehuda et al., 2015], [Sherin and Nemeroff, 2011] The diminished cortisol response contributes to persistent adrenergic hyperactivation, as the usual role of cortisol in dampening the adrenergic system is compromised. As a result, the adrenergic response remains heightened, promoting fear conditioning and intensifying alarm responses during trauma recall. [Zohar et al., 2011] Evidence suggests that low cortisol levels at the time of trauma may predict the development of PTSD, making hypocortisolemia a potential risk factor. This observation supports the hypothesis that early intervention with high-dose hydrocortisone post-trauma may prevent PTSD development. [Zohar et al., 2011] Click to enlarge. Downloadable with a Hub Pro subscription. 2. Interaction Between the HPA Axis, Hippocampus, and Prefrontal Cortex

• 21. The hippocampus and mPFC typically exert inhibitory control over the HPA axis. In PTSD, structural and functional deficits in these regions weaken this regulatory effect, contributing to the abnormal HPA feedback observed. The hippocampus, particularly vulnerable to prolonged cortisol exposure, exhibits impaired neurogenesis and reduced plasticity under sustained stress, which is commonly observed in PTSD patients. [Yehuda et al., 2015] This correlates with reduced hippocampal volume, as cortisol-induced damage impairs both memory processing and contextual learning of safety cues, perpetuating fear responses. The mPFC, which also modulates HPA activity, shows decreased volume and reduced connectivity with the amygdala in PTSD, contributing to its impaired ability to regulate stress responses. [Sherin and Nemeroff, 2011] 3. Sympathetic Nervous System and Adrenergic Overactivation In PTSD, the sympathetic nervous system plays a central role due to diminished cortisol responses that fail to adequately counteract adrenergic activity. The persistent adrenergic hyperactivation drives chronic symptoms like hypervigilance, heightened startle responses, and sustained anxiety. [Yehuda et al., 2015] Elevated levels of CRH in PTSD lead to blunted ACTH responses at the anterior pituitary due to the down-regulation of CRH receptors a compensatory mechanism driven by excessive CRH secretion. This dysfunction highlights a fundamental dysregulation in neuroendocrine signalling within PTSD, resulting in a persistent state of threat readiness. [Sherin and Nemeroff, 2011] 4. Genetic Contributions to HPA Axis Dysregulation in PTSD Two key genes implicated in the neuroendocrine dysregulation of PTSD are: 1. NR3C1 encodes the glucocorticoid receptor, which influences receptor sensitivity and feedback mechanisms. 2. FKBP5 is involved in immunoregulation and modulating glucocorticoid receptor availability. Alterations in FKBP5 expression have been linked to impaired HPA feedback and altered stress responses in PTSD. [Zohar et al, 2011]

• 22. Genetic variants affecting these genes can predispose individuals to abnormal glucocorticoid signalling, contributing to hypocortisolemia and the risk of developing PTSD following trauma exposure. 5. Implications for PTSD Treatment and Prevention The neuroendocrine profile in PTSD suggests that treatments targeting glucocorticoid signalling may offer therapeutic benefits. For instance, high-dose hydrocortisone administration soon after trauma exposure has shown promise in reducing PTSD risk, likely by normalizing HPA function and reducing subsequent adrenergic hyperactivation. [Zohar et al., 2011] Future interventions could explore genetic screening for vulnerabilities in NR3C1 and FKBP5, potentially identifying individuals at higher risk and guiding early, targeted treatments to prevent PTSD development. Click to enlarge. Downloadable with a Hub Pro subscription. Neurotransmitter Roles in PTSD: [Yehuda et al., 2015], [Sherin and Nemeroff, 2011] Serotonin: Altered 5-HT transmission in PTSD includes decreased serum 5-HT, altered 5-HT reuptake, and receptor changes, contributing to symptoms like hypervigilance,

• 23. impulsivity, and intrusive memories. Chronic stress upregulates 5-HT2 and downregulates 5-HT1A receptors, which correlate with anxiety and difficulty in fear extinction. Decreased serotonin transmission in the dorsal and median raphe is related to hypervigilance, increased aggression, and impulsivity, as well as the enhanced formation and resilience of intrusive memories, providing a role for SSRIs in the treatment of PTSD. 3,4-Methylenedioxymethamphetamine (MDMA) is being studied in the treatment of PTSD as it increases serotonin levels. [Sessa, 2017] The serotonin (5-HT) system influences both PTSD risk and symptom severity. Agents like meta-chlorophenylpiperazine (mCPP), which modulate serotonin receptors, can trigger anxiety, panic attacks, and other PTSD symptoms. While selective serotonin reuptake inhibitors (SSRIs) are effective in managing PTSD symptoms, they do not appear to prevent PTSD when administered immediately post-trauma, highlighting the complex role of serotonin in PTSD development. Noradrenaline: In PTSD, there is increased noradrenaline transmission in networks that connect the locus coeruleus to the amygdala and hypothalamus (the noradrenergic feed-forward circuit). The enhanced NA release is associated with increased fear conditioning, enhanced encoding of emotional memories, and increased arousal and vigilance. For example, yohimbine, an α2-adrenergic receptor antagonist, increases NA release, inducing flashbacks and increased autonomic responses in patients with PTSD. Along the same lines, propranolol administration (β2-adrenergic antagonist) after exposure to trauma can reduce PTSD symptom severity and reactivity to trauma cues. Dopamine Dopamine is implicated in the regulation of fear conditioning and anxiety. In addition, in individuals with PTSD, there is a genetic component associated with dopamine

• 24. metabolism that governs whether an individual develops PTSD and what symptoms they may display. Hypodopaminergia (due to genetic or epigenetic effects) is associated with an increased risk of developing PTSD. Combat stress responses have shown significant elevations of dopamine release (100 times above the resting state). This dopamine depletion, combined with trait hypodopaminergia, is postulated in the pathogenesis of PTSD. Hypodomainergia related to reward may also be linked to an increased risk of substance use disorders. [Blum et al., 2019] Dopamine release in the amygdala contributes to both unconditioned and conditioned stress responses. It can suppress prefrontal projections to the BLA, diminishing inhibitory control over fear responses and promoting hypervigilance. [Torrisi et al., 2019] Dopamine dysregulation is also evident in reward signalling within the NAc, which is often reduced in PTSD, particularly when comorbid with depression. Mesolimbic DA pathways, central to reward-seeking behaviour, are disrupted in PTSD, contributing to anhedonia and emotional numbing due to altered reward processing. Increased striatal dopamine transporter (DAT) density observed in PTSD suggests an aberrant DA-dependent reward system, contrasting with reduced DAT density in major depressive disorder (MDD) despite high comorbidity. PTSD is associated with hypoactivation of the NAc and PFC during reward processing, linking DAergic dysfunction to impaired decision-making. [Torrisi et al., 2019] Dopaminergic fibres from the ventral periaqueductal gray (vPAG) and DRN target the central amygdala (CEA), reinforcing fear memory through aversive prediction error signalling. [Torrisi et al., 2019] Dysregulation of the vPAG/DR-CEA circuitry, combined with a DA-related failure of PFC inhibition over the hyperactive CEA, may contribute to maladaptive fear memory formation in PTSD. DA systems may have therapeutic potential in PTSD, particularly by enhancing PFC activity to restore inhibitory control over limbic regions, reducing hyperarousal and intrusive symptoms. [Torrisi et al., 2019] Reactivating the PFC through increased DA signalling can promote fear extinction and resilience against PTSD.

• 25. Others Glutamate (excitatory) release via the NMDA receptors is involved in synaptic plasticity, learning and memory. GABA (inhibitory) release mediating anti-anxiety effects. Proinflammatory cytokines are involved in neuroinflammation. Endocannabinoids: Endocannabinoids (anandamide, 2-arachidonoylglycerol) mediate memory consolidation via CB1 receptors. In PTSD, the endocannabinoid (eCB) deficiency hypothesis suggests that stress exposure diminishes eCB signalling, particularly anandamide (AEA) and 2-AG, in cortico-limbic areas, leading to amygdala hyperactivity, reduced medial prefrontal cortex (mPFC) activity, and impaired stress regulation. This is especially relevant for individuals with emotion undermodulation. Pharmacological enhancement of eCB signalling can mitigate PTSD symptoms by normalising amygdala and mPFC function, reducing anxiety, suppressing traumatic memory recall, enhancing extinction, dampening inflammation, and improving sleep by decreasing REM sleep and arousal. [Hill et al., 2018] Medicinal Cannabis – Psychopharmacology and Clinical Application Neurosteroids (allopregnanolone) have an inhibitory effect on glucocorticoid and NA signalling. [Rasmusson et al., 2017] Neurosteroids such as allopregnanolone and pregnanolone enhance GABAergic signalling, offering neuroprotective benefits by increasing myelination and decreasing neuronal apoptosis. Lower levels of these neurosteroids have been associated with higher PTSD symptoms. Neurosteroids in Psychiatry – Pharmacology | Mechanisms of Action | Clinical Application Neuropeptides (neuropeptide Y, enkephalin endorphins, BDNF and DHEA) Dehydroepiandrosterone (DHEA), a precursor of androgens, is secreted alongside cortisol in response to ACTH stimulation. DHEA antagonizes GABA receptors while

• 26. facilitating NMDA receptor function, supporting neurocognitive resilience. [van Zuiden et al., 2017] Higher DHEA levels during stress may protect against the negative outcomes associated with PTSD, indicating its potential role as a biomarker for resilience. Opioids: During traumatic events, beta-endorphin levels initially rise, numbing emotional sensations. However, as trauma subsides, decreased beta-endorphin release results in withdrawal effects, contributing to PTSD symptoms. The kappa-opioid receptors (KORs), influenced by corticotropin-releasing factor (CRF) and dynorphin, are implicated in fear and stress behaviours. Treatment with buprenorphine/naloxone, which affects KORs, has shown a reduction in PTSD symptoms over a 24-month period. [Nikbakhtzadeh et al., 2020] In PTSD, the endogenous opioid system undergoes chronic downregulation, triggering conditioned passive defence responses and self-destructive behaviours as a means to increase opioid release during stress (e.g., self-harm). While mu-opioid receptors mediate analgesic effects, the kappa-opioid system influences consciousness alterations. This dysregulation is linked to dissociative symptoms, with increased kappa-opioid receptor activation in areas like the BNST contributing to enhanced claustrum connectivity, potentially leading to dissociation and dysphoria in PTSD with dissociative subtype. [Rabellino et al., 2017]

• 27. Click to enlarge. Downloadable with a Hub Pro subscription. PTSD AND NEUROINFLAMMATION Posttraumatic stress disorder (PTSD) has increasingly been linked to heightened systemic inflammation, highlighting its bidirectional nature where inflammation may both contribute to PTSD onset and be exacerbated by it. It is postulated to be a significant contributor to severity and treatment resistance. [Sumner et al, 2020] Neuroinflammation in Psychiatry Simplified – The Link Between the Immune System and The Brain- Dr Sanil Rege Exposure to traumatic events disrupts the sympathetic-adrenal-medullary (SAM) and hypothalamic-pituitary-adrenal (HPA) axes, resulting in cortisol dysregulation, including variations in secretion patterns. [Sun et al., 2021] Prolonged stress can induce glucocorticoid receptor resistance (GCR), promoting chronic inflammation and somatic diseases. This inflammatory state, characterised by elevated cytokines like IFN-γ, IL-6, TNF-α, and IL-17, signals a heightened proinflammatory status with increases in Th1 and Th17 immune cells. [Sun et al., 2021] Neuroinflammation plays a significant role in PTSD pathophysiology, with activation of neuroimmune cells such as microglia and astrocytes altering the neurobiological environment through the release of inflammatory markers. [Katrinli et al., 2022] Microglia, the resident immune cells of the central nervous system (CNS), play a critical role in synaptic pruning, chemotaxis, and neurogenesis under normal conditions. However, in PTSD, microglial activation becomes maladaptive, releasing both pro- and anti-inflammatory cytokines that disrupt homeostasis. These cytokines include IL-1β, TNFα, and IL-6, which further promote inflammation in the brain, affecting neural circuits involved in fear, memory, and emotional regulation. [Bonomi et al., 2024] Astrocytes also contribute significantly to neuroinflammation by releasing cytokines and regulating the blood-brain barrier (BBB) integrity.

• 28. They interact with microglia in a feedback loop, perpetuating the inflammatory response. Astrocytic dysfunction is potentially the main pathological basis for the co-morbidity of PTSD and sleep disturbances. [Li et al., 2022] Click to enlarge. Downloadable with a Hub Pro subscription. Astrocytic alterations are noted in PTSD models, such as changes in astrocytic processes, density, and neurotrophic factor production, including brain-derived neurotrophic factor (BDNF). [Li et al., 2023] Reduction in BDNF may impair synaptic plasticity and contribute to the cognitive and emotional deficits seen in PTSD patients. HPA axis dysregulation due to chronic trauma impacts cortisol feedback mechanisms, failing to inhibit proinflammatory cytokines and exacerbating neuroinflammation. [Li et al., 2023] This dysregulation facilitates cytokine signalling from peripheral to central pathways, affecting key brain regions like the amygdala and hippocampus. [Bonomi et al., 2024] Inflammation-induced changes in neurotransmitter synthesis affect serotonin, dopamine, and glutamate systems.

• 29. For example, cytokines upregulate the kynurenine pathway, depleting serotonin precursors and increasing neurotoxic quinolinic acid. [Katrinli et al., 2022] Additionally, cytokines affect dopamine synthesis by depleting tetrahydrobiopterin (BH4), a critical enzyme cofactor. [Katrinli et al., 2022] PTSD frequently coexists with immune-related conditions such as asthma, autoimmune diseases, and cardiovascular disorders, possibly due to shared inflammatory pathways. Increased levels of cytokines like IL-6, IL-17, and TNF-α link systemic inflammation to PTSD’s clinical manifestations. [Katrinli et al., 2022] Click to enlarge. Downloadable with a Hub Pro subscription. Clinical Implications: Elevated pro-inflammatory cytokines, such as IL-6 and TNF-α, have been observed in individuals with PTSD, correlating with worse clinical outcomes. [Sumner et al, 2020] Elevated levels of inflammatory biomarkers, such as white blood cell (WBC) counts, C-reactive protein (CRP), fibrinogen, and erythrocyte sedimentation rate (ESR), have been linked to worse clinical outcomes in PTSD. [Eswarappa et al, 2019] In particular, low cortisol levels, which also predict poor PTSD outcomes, further support the notion of dysregulated stress and immune responses in this condition.

• 30. Given the association between inflammation and poorer PTSD outcomes, addressing inflammation through targeted interventions could offer a novel therapeutic approach. [Eswarappa et al, 2019] Considering inflammation’s role in PTSD, anti-inflammatory treatments, including monoclonal antibodies and COX-2 inhibitors, have demonstrated the potential to reduce PTSD-like symptoms in preclinical models. [Katrinli et al., 2022] Additionally, adjunctive treatments with glucocorticoids, beta-blockers, and angiotensin receptor blockers are under investigation to mitigate inflammation and enhance outcomes. (See Anti-Inflammatory Treatments Later) ALLOSTATIC LOAD MODEL OF PTSD The allostatic load model describes how cumulative stress responses contribute to the development and persistence of PTSD. [Carbone et al., 2022] It highlights the concepts of allostasis, sensitization, and kindling as key mechanisms that lead to physiological dysregulation after repeated trauma exposure. [Burback et al., 2024] Sensitization involves an increased response to triggers over time, resulting in progressively heightened physiological reactions across biological systems in PTSD. Kindling refers to the underlying limbic abnormalities that emerge with repeated stress, increasing vulnerability to subsequent PTSD episodes. Together with fear conditioning and extinction failure, these processes are fundamental to PTSD’s onset and persistence. Repeated stress cycles disrupt neuroendocrine, neuroimmune, and cardiovascular systems, increasing allostatic load. Allostatic load reflects the “wear and tear” from chronic stress adaptation, marked by HPA axis dysregulation, immune changes, and structural and functional brain alterations (e.g., in the hippocampus, amygdala, and prefrontal cortex). [Carbone et al., 2022] When stress exceeds coping capacity, allostatic overload occurs, leading to sustained symptom severity and broader system failure. Biomarkers of allostatic load, such as cortisol, cytokines, and cardiovascular indicators, help quantify stress impact and guide targeted interventions. [Carbone et al., 2022]

• 31. Click to enlarge. Downloadable with a Hub Pro subscription. PTSD AND PAIN Posttraumatic stress disorder (PTSD) and chronic pain are intertwined through shared neural circuits and overlapping pathophysiological mechanisms. The ACC projects to the thalamus, amygdala, hypothalamus, and PAG, regulating autonomic responses and contributing to dysautonomias seen in chronic pain syndromes. [Fenton et al., 2015] Trauma-induced changes, such as increased amygdala sensitivity, HPA axis dysregulation, and altered dopaminergic signalling, heighten inflammation and amplify pain responses. This links adverse childhood experiences (ACEs) to both fibromyalgia and PTSD. [Gasperi et al., 2021] Individuals with co-occurring chronic pain and PTSD face more severe symptoms, including heightened pain intensity, emotional distress, and functional impairment, compared to those with either condition alone. [Scioli-Salter et al., 2015] The comorbidity rates are high, with 50-75% of PTSD patients reporting chronic pain, while 20-37% of chronic pain patients also meet PTSD criteria. [Scioli-Salter et al., 2015]

• 32. This comorbidity complicates treatment, as pain can act as a trigger for trauma-related memories, while trauma can exacerbate pain perception, creating a cycle of symptom amplification. Women who exhibit higher susceptibility to both conditions may experience symptom fluctuations related to hormonal variations, underscoring the need for tailored interventions. [Scioli-Salter et al., 2015] Neurobiologically, pain and PTSD share common pathways, such as the thalamusamygdala circuit, which processes pain as an unconditioned stimulus during traumatic events, activating survival-oriented defence responses. [Scioli-Salter et al., 2015] The parabrachial nucleus routes pain signals directly to the amygdala, reinforcing fear responses. Long-term potentiation (LTP) within the amygdala further establishes conditioned responses to trauma cues, including pain. [Scioli-Salter et al., 2015] Key neurotransmitters in both PTSD and chronic pain include Neuropeptide Y (NPY), allopregnanolone (ALLO), and the endogenous opioid and endocannabinoid systems. NPY, known for its antistress and antinociceptive effects, is reduced in both conditions, correlating with heightened symptoms. ALLO, which facilitates GABAergic transmission, has anxiolytic and analgesic properties but is often deficient in PTSD and chronic pain. Dysregulated opioid pathways in PTSD contribute to reduced pain thresholds, while the modulation of endocannabinoid signalling shows promise in enhancing fear extinction, potentially benefiting patients with comorbid pain and PTSD. [Scioli-Salter et al., 2015] Shared serotonergic, noradrenergic, and dopaminergic dysfunctions not only contribute to maladaptive responses in PTSD but also play a pivotal role in the development of comorbid pain syndromes. Noradrenergic Dysfunction in Pain and PTSD:

• 33. Noradrenergic dysregulation, particularly involving the locus coeruleus, amplifies descending pain pathways and perpetuates hyperarousal, increasing pain perception. Impaired noradrenergic inhibition disrupts the modulation of pain signals, leading to hyperarousal and increased pain perception. [Vieira et al., 2021] Additionally, noradrenergic inputs contribute to altered thalamocortical rhythms, which can drive autonomic dysregulation, facilitating the transition from acute to chronic pain. [Fenton et al., 2015] This overlap between noradrenergic dysfunction in PTSD and its role in pain modulation helps explain why individuals with PTSD often experience increased pain sensitivity and persistent pain syndromes. Serotonergic Dysfunction in Pain and PTSD: 5-HT is a key neurotransmitter that modulates synaptic transmission and plasticity across the central nervous system (CNS), influencing diverse processes, including mood regulation, pain perception, and emotional responses. In regions like the ACC, insula, and amygdala, serotonin exerts both excitatory and inhibitory effects, depending on the receptor subtype and neural circuits involved. [Hao et al., 2023]. This modulation extends to the descending pain pathways, where 5-HT can enhance or inhibit pain perception. Altered serotonergic projections from the amygdala to the prefrontal cortex mediate anxiety-induced hyperalgesia, linking the emotional dysregulation characteristic of PTSD to pain hypersensitivity. [Fenton et al., 2015] Dopaminergic Dysfunction in Pain and PTSD: Dopaminergic dysfunction in PTSD plays a critical role in both reward processing and pain modulation. Low extracellular dopamine levels correlate with increased pain sensitivity, as reduced dopamine impairs the brain’s reward circuits, which are essential for regulating both

• 34. pleasure and pain perception. [Fenton et al., 2015] In the ventral striatum, this diminished dopamine signalling is associated with anhedonia and emotional numbing, core features of PTSD that further contribute to heightened pain perception. Additionally, increased striatal dopamine transporter (DAT) density has been observed in PTSD, indicating aberrant dopaminergic activity. This increase in DAT density is linked to hyperdopaminergia, which may disrupt standard reward processing, thereby exacerbating pain symptoms. Striatal D2 receptor activation plays a compensatory role by enhancing descending pain inhibition through serotonergic and dopaminergic pathways in the spinal cord. [Fenton et al., 2015] D2 receptor activation has been shown to reduce persistent pain by inhibiting rostral ventromedial medulla (RVM) nociceptors, which are central to pain modulation. However, patients with low endogenous dopamine levels rate pain stimuli as more intense, reflecting the link between impaired dopaminergic signalling and increased pain perception. [Fenton et al., 2015] In PTSD, this dopaminergic dysfunction reduces top-down control from the prefrontal cortex over subcortical pain circuits, leading to persistent pain and maladaptive stress responses. D2-like receptor agonists, when combined with μ-opioid receptor agonists, may offer improved analgesic effects, highlighting the potential therapeutic role of dopamine modulation in managing comorbid pain and PTSD. [Wang et al., 2021] Dysfunction in the top-down regulation by the vmPFC, combined with enhanced afferent signalling, drives stress-induced sensitisation, facilitating the progression from acute to chronic pain. [Fenton et al., 2015] Importantly, patients with PTSD often exhibit paradoxical pain responses, including both hyposensitivity associated with dissociation and hyperresponsiveness linked to anxiety,

• 35. reflecting broader dysregulation within corticolimbic networks. [Defrin et al., 2015] This highlights the necessity for integrated treatments targeting the shared neurobiological substrates of PTSD and chronic pain, as treating one condition in isolation may yield suboptimal outcomes. Therapeutic approaches targeting NPY, ALLO, and the endocannabinoid system offer potential pathways for managing this comorbidity, emphasising personalized treatments based on neurobiological profiles and sex differences. [Scioli-Salter et al., 2015] Integrative strategies, such as cognitive-behavioural therapies, may enhance pharmacological interventions by improving amygdala regulation, as suggested by functional neuroimaging studies of prefrontal cortex modulation. Click to enlarge. Downloadable with a Hub Pro subscription. NEUROBIOLOGICAL CORRELATES OF PTSD SYMPTOMS 1.Intrusion Symptoms [Ressler et al., 2022] Amygdala Hyperactivity: Drives intrusive memories, flashbacks, and heightened emotional reactivity to trauma-related cues, even in safe environments.

• 36. Hippocampal Dysfunction: Disrupts contextual memory processing, contributing to the misinterpretation of neutral stimuli as threats. Prefrontal Cortex (PFC) Dysregulation: Decreased inhibition of intrusive memories, exacerbating the re-experiencing of traumatic events. DMN alteration may contribute to rumination and alterations in self-awareness. [Daniels et al., 2011] In PTSD, especially from early-life trauma, DMN disruptions—marked by reduced connectivity and myelination (e.g., lower corpus callosum integrity)-impair selfreferential processing, emotion recognition, and autobiographical memory. This contributes to symptoms like alexithymia, dissociation, and altered self-perception. [Daniels et al., 2011] 2. Sleep Disturbances 70-90% of individuals with PTSD report sleep disturbances, with insomnia and nightmares being key symptoms. [Lancel et al., 2021] Pre-existing sleep problems increase the vulnerability to PTSD, while persistent sleep disturbances often continue even after other symptoms improve. Disrupted Sleep Architecture: PTSD is associated with increased time in light sleep, reduced slow-wave sleep, and fragmented REM sleep, impairing restorative sleep functions. [Shalev et al., 2024] A meta-analysis of polysomnographic studies has shown a pattern of more N1 and less N3 sleep as well as greater REM density in PTSD populations, making sleep in PTSD, in general, more superficial and less regenerative. In addition, there are indications that several aspects of sleep, such as sleepdisordered breathing, worsen with a longer duration of the disorder and, together with obesity, contribute to premature cognitive ageing. [Nijdam et al., 2023] REM Sleep and Nightmares:

• 37. Frequent nightmares often occur during REM sleep, as this phase is involved in fear memory consolidation, contributing to trauma reactivation. [Pace-Schott et al., 2015] 3. Hypervigilance Acute-Threat Response: Hypervigilance in PTSD is driven by the brain’s acute-threat response system, which maintains heightened alertness and reactivity to potential dangers. Amygdala and dACC Overactivity: Increased activity in the amygdala, dorsal anterior cingulate cortex (dACC), and insula heightens threat detection, leading to a constant sense of danger. Amplified Startle Response: PTSD patients exhibit an exaggerated startle reflex, indicating persistent hyperarousal and vigilance even in non-threatening settings. Physiological Correlates: Elevated heart rate, increased skin conductance, and dysregulated HPA axis responses are common, contributing to sustained arousal. 4. Persistence of PTSD Symptoms [Shalev et al., 2024] Kindling Hypothesis: Repeated trauma exposure reinforces maladaptive neural activation patterns, making symptoms more resistant to extinction. Allostatic Load: Chronic stress causes “wear and tear” on emotion regulation systems, especially in the hippocampus, compromising safety signal integration. Impaired Extinction Learning:

• 38. Deficits in the prefrontal cortex and hippocampal function hinder the extinction of fear memories, promoting chronic symptom persistence. Persistent Hyperexcitability: Persistent hyperactivity in fear circuits reinforces the recurrent nature of intrusive symptoms in PTSD. [Rosen & Schulkin, 2022] Endocrine Dysregulation: Persistent HPA axis dysfunction, marked by increased CRF signalling, amplifies noradrenergic activation and disrupts top-down control from the prefrontal cortex, sustaining hyperarousal and impeding fear extinction in PTSD. Click to enlarge. Downloadable with a Hub Pro subscription. PTSD PHENOTYPES The dynamic interaction between the mPFC and the amygdala creates two distinct phenotypes in PTSD patients. [Yehuda et al., 2015], [Lanius et al., 2010], [Lanius et al., 2018] 13–30% of individuals with PTSD meet the criteria for the dissociative subtype. [Fenster et al, 2018].

• 39. Click to enlarge. Downloadable with a Hub Pro subscription. Emotional Undermodulation (PTSD + Hyperarousal): Diminished vmPFC inhibition of the amygdala and BNST leading to increased threat expression and reduced fear extinction. Bottom-up processing from the PAG to the bilateral CMA and from the BLA to the vmPFC suggests defensive responding and chronic fear responses driven by midbrain and limbic regions. Chronic PTSD is associated with elevated BNST activity, which impairs the HPA Axis, leading to enhanced processing of negatively valenced information. Hyperarousal is mediated by noradrenergic projections to the BNST and negative valence by serotonergic inputs abundant in the BNST. Emotional Overmodulation (PTSD + Dissociative Subtype): The VMPFC shows increased inhibition of the amygdaloid complexes. Predominant top-down connectivity between the bilateral CMA and PAG and vmPFC with the BLA is associated with symptoms of depersonalisation, derealisation and dissociative features.

• 40. Click to enlarge. Downloadable with a Hub Pro subscription. INTEGRATED NETWORK MODEL OF PTSD Three key brain networks have been identified as central to higher cognitive functions: Salience Network (SN): Anchored in the anterior cingulate cortex and ventral anterior insula and involves the amygdala and thalamus. Detection of salient internal and external stimuli to direct behaviour Dysfunction in this network can give rise to alterations in arousal The SN processes “bottom-up” aversive or other salient attention-demanding stimuli or experiences. Default Mode Network (DMN): Anchored in the medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC), and angular gyrus. Involved in emotional regulation, social cognition, future-oriented thinking, autobiographical memory, self-awareness, and perspective-taking Dysfunction in this network can alter the cognitive processing of external information and relating it to the self. (self-referential processing)

• 41. Central Executive Network (CEN) or Executive Control Network (ECN): Anchored in the dorsolateral prefrontal cortex (dlPFC) and posterior parietal cortex. Seat of executive functioning, cognitive control and working memory Dysfunction in this network leads to cognitive dysfunction Integrated (Triple) Network Model of PTSD: [Hinojosa et al., 2024] Disruptions in these networks in PTSD manifest through abnormal connectivity and activation patterns, contributing to symptoms like hyperarousal, re-experiencing, and deficits in emotional regulation. [Yehuda et al., 2015] Increased activation of the amygdala and dACC within the SN is linked to hyperarousal and hyperreactivity in PTSD. Reduced activation in the hippocampus and vmPFC, part of the DMN, correlates with intrusive memories, impaired fear extinction, and emotional regulation deficits. Decreased activation in CEN regions is associated with impaired cognitive control and executive function in PTSD patients. Connectivity patterns vary, with decreased DMN connectivity at rest, increased SN activation during threat processing, and reduced CEN connectivity. Impaired connectivity between the SN and DMN limits transitions between selfreferential states and cognitive control, while increased CEN influence on the DMN indicates abnormal modulation. PTSD patients show a shift to a “small-world” network topology, marked by greater network segregation and reduced integration, particularly within the DMN. Greater network segregation, especially in the DMN, and decreased hippocampusPFC connectivity are associated with more severe re-experiencing symptoms. Both within-network coherence and between-network dynamics contribute to the persistence of PTSD symptoms and treatment resistance.

• 42. Click to enlarge. Downloadable with a Hub Pro subscription. STAGING MODEL OF PTSD Recently, a staging model of PTSD has been proposed, emphasising a four-stage trajectory ranging from trauma exposure without symptoms (Stage 0) to severe, unremitting chronicity (Stage 4). [Nijdam et al., 2023] The aims of the Stage-Specific model of PTSD are to: 1. Organise PTSD progression using neurobiological markers, stress reactivity, information processing, and consciousness dimensions to guide interventions. 2. Integrate neurobiological and phenomenological factors to enhance understanding of PTSD’s development, allowing for personalised, phase-specific care. 3. Address treatment resistance by matching interventions to the neurobiological state at each stage, improving precision. 4. Enable early intervention by identifying initial risk stages and focusing on preventing chronic PTSD. 5. Tailor treatment based on symptom severity, functional impact, and evolving clinical data, supporting individualised care trajectories. 6. Incorporate transdiagnostic perspectives to address a range of posttraumatic conditions, enhancing comprehensive management. 7. Refine intervention timing and methods for better outcomes in PTSD treatment.

• 43. Click to enlarge. Downloadable with a Hub Pro subscription. TREATMENT OF PTSD - GENERAL PRINCIPLES PTSD’s pathogenesis, as illustrated in the diagram, centres on two critical processes: Kindling: This process involves increasingly low-severity stimuli, triggering negative responses over time. Sensitization: Repeated exposure to negative stimuli leads to progressively stronger responses. Effective treatment aims to achieve fear extinction and desensitization while intervening in the kindling process.

• 44. Click to enlarge. Downloadable with a Hub Pro subscription. Traditionally, PTSD treatments have targeted abnormal fear circuits and trauma-related cognitions, utilising exposure-based psychotherapies and medications focused on anxiety and hyperarousal. While global treatment guidelines may differ slightly, Cognitive Behavioral Therapy (CBT) and selective serotonin reuptake inhibitors (SSRIs) are commonly recommended as firstline interventions. [Burback et al., 2024] Prazosin is often considered for managing nightmares, though guidelines vary in its recommendation. Recent evaluations call for updated guidelines that now incorporate complex PTSD (CPTSD) considerations, as seen in the Australian guidelines. [Burback et al., 2024] Trauma-Focused Psychotherapies (TFPs) have demonstrated superior effectiveness; however, guideline variations reflect differing perspectives on pharmacotherapy’s role, considering its limitations and patient preferences. [Burback et al., 2024] SUMMARY OF GUIDELINES FOR PTSD A systematic review of clinical guidelines for PTSD treatment reveals several consensus recommendations, with some variability in details.

• 45. Key recommendations include: [Martin et al., 2021] Pharmacological Treatment: SSRIs are universally endorsed as first-line treatment for PTSD, particularly paroxetine and fluoxetine, along with the SNRI venlafaxine. These medications have shown statistically significant but modest improvements in PTSD symptoms compared to placebo, similar to their effects in depression. TCAs are suggested as an alternative first-line option by the WHO, mainly when SSRIs or venlafaxine are unavailable, ineffective or if severe comorbid depression is present. However, TCAs generally have less supporting evidence and greater concerns regarding side effects. Some research suggests comparable efficacy to SSRIs in combat-related PTSD, indicating the need for further investigation. Psychotherapy vs. Pharmacotherapy: Approximately one-third of guidelines prioritise trauma-focused psychotherapies (e.g., TF-CBT, EMDR) over pharmacotherapy as first-line treatments, supported by meta-analyses showing larger effect sizes for psychotherapies compared to medications. However, the choice between therapy and medication should be based on patient preference, availability, and comorbid conditions like depression. CBT, particularly trauma-focused modalities like Cognitive Processing Therapy (CPT), Prolonged Exposure (PE), and Image Rehearsal Therapy (IRT), is the preferred first-line psychological treatment. EMDR is often recommended separately, although both EMDR and CBT demonstrate comparable efficacy. The use of the broader term “trauma-focused psychotherapies” may reduce confusion and allow treatment flexibility. Nightmares in PTSD: While nightmares are often resistant to treatment and associated with higher suicide risk, most guidelines lack detailed recommendations.

• 46. Prazosin is considered a first-line treatment for nightmares by two guidelines, but others either recommend it as a third-line or do not mention it specifically. Meta-analyses show significant effectiveness of prazosin, but recent trials with larger samples report mixed results, suggesting it may be effective for specific subgroups with severe adrenergic dysfunction. IRT is another recommended treatment for nightmares, with evidence suggesting it is as effective as prazosin, especially when combined with CBT for insomnia. IRT has a more extensive evidence base yet appears less frequently in guidelines compared to prazosin. In summary, guidelines generally favour SSRIs, trauma-focused psychotherapies, and prazosin or IRT for targeted symptom management, though treatment should be individualised based on patient characteristics and preferences. Further research is needed to clarify subgroup responses, particularly for nightmares and combat-related PTSD. PSYCHOTHERAPY IN PTSD Psychotherapy can be divided into trauma-focused and non-trauma-focused psychotherapy. Trauma-focused CBT has been extensively studied and shown to be effective. Prolonged exposure (PE) therapy and cognitive processing therapy (CPT) are two types of trauma-focused CBT. Repeatedly writing and talking about the details of the traumatic memory are central therapeutic elements of both Cognitive Processing Therapy (CPT) and Prolonged Exposure (PE). They are based on the principles of extinction learning, habituation and desensitisation. Trauma-focused therapy Prolonged exposure therapy (PET): [Schnyder et al., 2015] Two key components:

• 47. 1. Imaginal Exposure: Revisiting trauma memories with the processing of emotions. 2. In Vivo Exposure: Gradual exposure to avoided, safe situations. Successful treatment requires two conditions: activation of trauma memory and disconfirmation of expected harm, both validated as mechanisms for reducing PTSD symptoms. Based on Emotional Processing Theory, PE activates trauma memory and disconfirms expected harm, reducing PTSD symptoms. Reductions in negative cognitions are central to symptom improvement Cognitive-processing therapy (CPT): [Resick & Schnicke, 1992] Uses education and cognitive restructuring without detailed trauma recounting. CPT without trauma accounts (CPT-C) shows faster improvement through Socratic dialogue. The focus is on beliefs about the trauma rather than reexperiencing it. It also addresses shame, guilt or feelings of mistrust. Present-Centered Therapy (PCT) effectively addresses PTSD by focusing on current symptoms, not trauma memory. Both CPT and PCT demonstrate that PTSD can be treated without detailed trauma exposure. In this sense, culturally adapted CBT has also been useful as this technique offers a more specific paradigm to treat PTSD. Narrative exposure therapy (NET): This therapy was developed for the survivors of the Pinochet regime in Chile and has proven to be very useful in overcoming trauma. Addresses cumulative trauma by helping individuals construct a chronological life story that includes both traumatic and positive events. Focuses on recalling the most distressing experiences while maintaining a connection to the “here and now,” linking emotional responses to their autobiographic context.

• 48. Encourages reliving sensory, emotional, and physiological trauma memories to foster exposure and reduce avoidance. Integrates positive memories to mobilize personal resources, promoting healing and therapy continuation. Proven effective in reducing PTSD symptoms, improving psychosocial functioning, and enhancing physical health. Emphasises processing of trauma and associated guilt or shame, particularly for excombatants, to aid reintegration. It is recommended for adults with PTSD where trauma is linked to genocide, civil conflict, torture, political detention, or displacement. Eye Movement Desensitization and Reprocessing (EMDR) [Shapiro, 2014] Eight-phase approach focused on processing unintegrated trauma memories linked to current dysfunction. Clients briefly focus on trauma images, negative beliefs, and bodily sensations, with short exposures paired with bilateral eye movements. EMDR reduces arousal, negative affect, and memory vividness, creating connections to adaptive memory networks. Key elements include stabilization, memory processing, and skills training for social interactions. Effective across past memories, present triggers, and future challenges, promoting adaptive functioning in daily life. Stress inoculation training (SIT): [Meichenbaum, 1985] SIT is based on the concept of inoculation, helping clients recognize and modify maladaptive stress behaviours. EMDR is a “A therapy aiming to process distressing memories by having the patient recall distressing images while receiving one of several types of bilateral sensory input, including side-side eye movements” – [Yehuda et al., 2015] 

• 49. It increases awareness of personal narratives that sustain distress. SIT is a flexible, tailored form of cognitive-behavioural therapy to reduce stress responses. It can be considered for adults with PTSD where trauma-focused cognitive behavioural therapies or EMDR are unavailable or unacceptable. Non-trauma-focused therapy Supportive therapy Non-directive counselling Mindfulness and patient-centred therapy Interpersonal therapy Yoga and mindfulness training “Patients with a history of interpersonal violence, early life trauma or those with a complex presentation of PTSD that includes emotional detachment might be better treated with phase-oriented approaches. Phase oriented approaches involve skills training, mood regulation and grounding, identifying attachment schemas and developing competence in social interactions. Once these skills have been developed, the patient can then participate in modified exposure-based therapy focusing on emotional stability and negative personal schemas.” – [Yehuda et al., 2015] Prolonged Exposure (PE), Cognitive Processing Therapy (CPT), and trauma-focused CBT are recommended as first-line PTSD treatments by the APA and VA/DoD, supported by strong evidence. [Martin et al., 2021] Research shows they are equally effective, with patients, including veterans, preferring these therapies over psychodynamic approaches, EMDR, or medications, favouring exposure-based methods and CBT. A review of 70 studies covering 4,761 participants evaluated various psychotherapies for PTSD, revealing small sample sizes, potential bias, and limited follow-up data. [Bisson et al., 2013]

• 50. Key findings: Trauma-focused CBT (TF-CBT) and EMDR are effective in reducing PTSD symptoms, with TF-CBT showing superiority over present-centred therapy shortly after treatment EMDR may require booster sessions for sustained results. Cognitive Processing Therapy (CPT) is particularly effective in chronic PTSD cases. Interpersonal Therapy (IPT) performs comparably to prolonged exposure in those with comorbid depression, suggesting that direct trauma exposure may not be essential for effective treatment. Psychotherapy for Military-Related PTSD: A review of 36 controlled trials shows that trauma-focused therapies and CPT benefit about 60% of veterans but have high dropout rates, with over two-thirds remaining symptomatic, indicating a need for alternative approaches. [Steenkamp et al., 2015] Non-trauma-focused therapies provide a less intensive option, supporting sustained care and engagement when trauma-focused treatments are not well tolerated. Psychological Therapies for Children and Adolescents CBT was most effective for children and adolescents, with improvements lasting up to one year. [Gillies et al., 2013]. Psychological interventions overall showed significant short-term benefits within a month of completion. Early Psychological Interventions for Preventing PTSD Psychological Debriefing: Found ineffective and potentially harmful, leading to its exclusion from modern guidelines. CBT for Preventing PTSD: [Shalev et al., 2024]

• 51. Exposure-based CBT can effectively reduce PTSD symptoms in early intervention stages, especially among sexual assault survivors. Optimal when provided after confirmed PTSD diagnosis rather than immediately post-trauma. Diluted or remotely delivered CBT forms are less effective, emphasizing the need for structured, direct approaches. In summary, while CBT remains the primary strategy for preventing PTSD progression, its early implementation may not suit all survivors, suggesting the need for additional interventions targeting non-remitting cases. PHARMACOTHERAPY IN PTSD When reviewing methodologically robust pharmacotherapy trials, Hoskins and colleagues found that amongst antidepressants, only fluoxetine, sertraline, paroxetine, and venlafaxine have statistically significant data on reducing PTSD symptoms compared to placebo. [Hoskins et al, 2021] Quetiapine has evidence when used as monotherapy. Prazosin and risperidone show benefits as augmentation agents. [Hoskins et al, 2021] SSRIs (Selective Serotonin Reuptake Inhibitors) SSRIs remain the first-line treatment for PTSD, with sertraline and paroxetine approved by the FDA. These medications are effective in reducing re-experiencing, avoidance, and numbing symptoms but are less effective for hyperarousal. [Shalev et al., 2024] Paroxetine has shown better efficacy than sertraline in clinical trials, particularly for civilian females, but carries side effects like sedation, weight gain, and sexual dysfunction. Withdrawal can also be problematic, making it less desirable for women of childbearing age due to its pregnancy risk. [Bajor et al., 2022] Sertraline, while also effective, has demonstrated mixed results, especially in male veterans. It is generally better tolerated than paroxetine, with fewer side effects related to sedation and weight gain. While escitalopram and citalopram have shown mixed results, they may be considered alternatives due to their milder safety profiles.

• 52. SNRIs (Serotonin-Norepinephrine Reuptake Inhibitors) Venlafaxine is the most studied SNRI for PTSD, demonstrating similar efficacy to SSRIs, particularly for re-experiencing and avoidance. [Davidson et al., 2006] However, it has a limited impact on hyperarousal and can exacerbate insomnia, making it a second-line option. Side effects of venlafaxine include sexual dysfunction and potential cardiovascular concerns, which should be considered when treating PTSD patients with preexisting heart conditions. [Davidson et al., 2006] Tricyclic Antidepressants (TCAs) TCAs, such as imipramine and amitriptyline, can be beneficial in PTSD but are generally reserved for cases where SSRIs or SNRIs are ineffective or not tolerated due to side effects. [Davidson, 2015] These medications are associated with significant anticholinergic effects, cardiac risks, and overdose potential, necessitating careful monitoring, especially in patients with suicidal ideation. [Kosten et al., 1991] Revisiting Tricyclic Antidepressants: Understanding the Differences and Advantages for Effective Depression Treatment MAOIs (Monoamine Oxidase Inhibitors) MAOIs have shown limited evidence in PTSD treatment but may be useful in select cases where other antidepressants have failed. [Ipser & Stein, 2012] Strict dietary restrictions and potential severe side effects, including hypertensive crises, limit their use to highly resistant cases. Monoamine Oxidase Inhibitors (MAOI) – Mechanism of Action | Psychopharmacology | Clinical Application Atypical Antipsychotics Risperidone, quetiapine, and olanzapine are often used as adjuncts to antidepressants in treatment-resistant PTSD, helping with re-experiencing and hyperarousal symptoms. [Krystal et al., 2011]

• 53. Risperidone: While it has shown some benefit in reducing re-experiencing, a large RCT found no significant difference compared to placebo for core PTSD symptoms, though secondary analyses suggested mild improvements in sleep. [Krystal et al., 2016] Quetiapine: It has demonstrated improvement in overall PTSD symptoms, particularly insomnia, but is associated with metabolic side effects, weight gain, and sedation. [Villarreal et al., 2018] Olanzapine: Shows benefits for avoidance and numbing symptoms but has a high risk of weight gain and metabolic syndrome. [Carey et al., 2012] A Simplified Guide to Oral Antipsychotic Medications – Mechanism of Action, Side Effects and Need to Know Points Anti-adrenergic drugs (α1, α2 and β receptors) (e.g. prazosin, guanfacine, alfuzosin, doxazosin, propranolol and clonidine). Alpha-1 Adrenergic Antagonists Prazosin: Prazosin is effective in reducing nightmares and improving sleep quality in PTSD, with studies suggesting that higher pretreatment blood pressure predicts better outcomes. [Raskind et al., 2018] A Systematic review and meta-analysis showed that Prazosin shows good evidence in the treatment of PTSD with a positive effect on PTSD scores, nightmares and sleep quality. [Reist et al., 2021] Treatment of PTSD with prazosin is usually initiated at a dose of 1 mg, with monitoring for hypotension after the first dose. The dose is then gradually increased to maintenance levels of 2-6 mg at night. In treating PTSD-related symptoms, prazosin’s mean optimal dose is generally 16 mg nightly for men (with some requiring up to 25–30 mg) and 7 mg nightly for women. Studies of military patients with PTSD have used higher doses (e.g., 10-16 mg at night), with the maximum dose used clinically without side effects at 50 mg /day. [Koola et al., 2014] Due to its short half-life, BD or TDS dosing may be required.

• 54. Doxazosin Doxazosin, an alternative to prazosin, offers a longer half-life and potentially fewer side effects, making it an option for patients who struggle with prazosin’s hypotensive effects. [Rodgman et al., 2016] Once daily dosing. Dose: 8 to 16 mg/day. (Higher doses of up to 48 mg /day have been used. Smith and Koola, Unpublished). Clonidine: Alpha-2 presynaptic agonist: Clonidine has shown promise in reducing PTSD severity, particularly in veterans, as indicated by significant improvements on the Clinical Global Impression (CGI) scale. [Burek et al., 2021] It is used primarily for managing nighttime symptoms, including nightmares and sleep disturbances, by acting centrally to inhibit noradrenaline release, leading to decreased arousal and improved sleep quality [Wendell & Maxwell, 2015] Clonidine’s action on the locus coeruleus is thought to contribute to its hypnotic effects, pain signal modulation, and reduction of anxiety and depressive symptoms. Compared to prazosin, clonidine’s effects may be more centrally mediated, affecting noradrenaline release and sensitivity, which could help desensitize the noradrenergic system, potentially reducing hypervigilance, insomnia, flashbacks, and nightmares. Clonidine’s impact on REM and non-REM sleep could enhance memory consolidation, which may benefit emotional memory processing and overall PTSD symptomatology. [Miyazaki et al., 2004]; [Lebow & Chen, 2016] Adverse effects during low-dose clonidine use are generally minor, but include potential sedation, hypotension, and dry mouth, which may limit tolerability in some patients. [Detweiler et al., 2016] Studies suggest that clonidine may be comparable to other anti-adrenergic drugs like prazosin, but definitive evidence regarding its superiority or optimal dosing in PTSD treatment is still lacking. [Marchi et al., 2024] Doses below 0.05 mg daily have been reported as ineffective, while doses above 0.25 mg did not yield additional benefits, indicating a potential dose-dependent effect for PTSD-related symptoms, though more research is needed to determine the optimal dosing strategy. [Burek et al., 2021]

• 55. Despite mixed evidence and a lack of large-scale trials, clonidine may offer an alternative for individuals with PTSD who do not respond to or cannot tolerate other anti-adrenergic agents, particularly for reducing sleep-related symptoms. [Reist et al., 2021] Psychopharmacology and Clinical Application of Guanfacine and Clonidine for ADHD – What’s the Difference? Sleep Medications: Trazodone is widely used to manage PTSD-related insomnia, with efficacy attributed to its effects on serotonin, alpha-1 adrenergic, and histamine receptors. It is well tolerated but has potential side effects like sedation and orthostasis. Suvorexant, an orexin antagonist, has shown promise in managing trauma-related insomnia by reducing sleep onset latency and increasing sleep duration. Benzodiazepines are not recommended for PTSD, as they lack efficacy for core symptoms and have a high potential for dependence, particularly in trauma-exposed populations. Benzodiazepines are also associated with a 150% increased risk of PTSD development post-trauma. [Campos et al., 2022] Benzodiazepines can exacerbate avoidance and depressive symptoms, most likely due to their strong sedative, addictive, and dissociative properties. [Du, et al, 2022] A review of 99 RCTs involving 10,481 participants found that prazosin may be the most effective treatment for insomnia, nightmares, and poor sleep quality in PTSD. In contrast, SSRIs, mirtazapine, Z-drugs, and benzodiazepines showed limited efficacy, while risperidone and quetiapine posed high risks of somnolence without clear benefits. Hydroxyzine, trazodone, nabilone, paroxetine, and MDMA-assisted psychotherapy show promise but require further research. [Lappas et al., 2024] Ketamine: Intravenous ketamine has demonstrated rapid reductions in PTSD symptoms, particularly for depressive comorbidity, with benefits lasting up to six weeks after multiple doses. [Feder et al., 2021] Its potential for misuse requires careful monitoring and consideration in treatmentresistant cases.

• 56. Ketamine and Esketamine in Depression – A Synopsis on Efficacy and Mechanism of Action Memantine: Memantine, a glutamatergic modulator, has shown promising results in reducing PTSD symptoms. Preclinical findings suggest that memantine enhances hippocampal neurogenesis, aiding in the forgetting of traumatic memories and reducing anxiety-like behaviours. [Ishikawa et al., 2019] In an open-label trial among civilian female PTSD patients, memantine significantly improved PTSD symptoms and was well tolerated. [Hori et al., 2021] An open-label trial of memantine in veterans improved cognitive symptoms, PTSD symptoms, and mood. [Ramaswamy et al., 2015] Memantine – Mechanism of Action | Psychopharmacology | Clinical Application Lamotrigine: Lamotrigine may be effective in treating PTSD, particularly for intrusive and avoidance/numbing symptoms, with responses observed across genders and trauma types. However, the small sample size limits the assessment of effect size. [Hertzberg et al., 1999] Lamotrigine – Mechanism of Action, Efficacy, Side Effects and Clinical Pearls Topiramate: Topiramate showed a medium but not significant effect on overall PTSD symptoms, with a small, significant reduction in hyperarousal. [Varma et al., 2018] It did not significantly impact reexperiencing or avoidance symptoms, with similar results across veterans and nonveterans, and as both monotherapy and adjunctive therapy. Cannabis and Cannabidiol (CBD)

• 57. Preliminary evidence suggests cannabis may reduce overall PTSD symptoms, but high-quality data is lacking. Side effects, such as psychoactive responses and potential worsening of symptoms, limit its use in clinical practice.[Bedard-Gilligan et al., 2018] A recent meta-analysis suggested that while cannabinoids may offer some therapeutic potential for reducing PTSD symptoms related to intrusion (cluster B) and arousal/reactivity (cluster E), these benefits are limited and must be viewed within a broader risk context. Cannabinoids have been associated with increased suicidal ideation and aggressive behaviour, particularly among individuals with comorbid cannabis use disorder (CUD). In a small study (n=10), 5 mg of THC twice daily as an add-on improved sleep, reduced nightmares, hyperarousal, and overall PTSD symptom severity. [Roitman et al., 2014] Similarly, the THC analogue nabilone showed benefits in sleep and symptom reduction. However, the positive effects of THC appear limited, leaving many PTSD features unchanged. [Jetly et al., 2015] Medicinal Cannabis – Psychopharmacology and Clinical Application Reconsolidation Therapy (RT) Propranolol-induced reconsolidation impairment effectively reduces recall of aversive memories and emotional responses, showing benefits in alleviating psychiatric symptoms and cue reactivity in conditions like PTSD, addiction, and phobia, compared to placebo. [Pigeon et al., 2022] An updated meta-analysis found no significant effect compared to placebo in disrupting traumatic memory consolidation. [Steenen et al., 2022] Novel and Emerging Treatments Anti-Inflammatory Agents: [Lee et al, 2022]. ACE Inhibitors and ARBs (e.g Captopril, Candesartan, Telmisartan):

• 58. Prevent synthesis of ACE inhibitors or block ARB angiotensin II receptors, reducing inflammation. Cannabis e.g Nabilone: Enhances endocannabinoid signalling with anti-inflammatory effects. Glucocorticoids (e.g. Hydrocortisone, Prednisolone, Dexamethasone): Inhibits cytokine expression via genomic mechanisms. Monoclonal Antibodies Against Cytokines (e.g. Infliximab (anti-TNF-α), Adalimumab (anti-TNF-α), Tocilizumab (anti-IL-6 receptor). Prevent cytokines from binding to their receptors, reducing inflammation. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) (e.g Celecoxib, Ibuprofen, Naproxen): Inhibit COX-2, reducing pro-inflammatory cytokine production. Neurofeedback: [Askovic et al., 2023] Neurofeedback is postulated to reduce nervous system arousal and enhance connectivity within the Default Mode and Salience Networks when introduced early in PTSD treatment. It improves brainwave synchrony, normalises network connectivity, and restores the brain’s excitatory/inhibitory balance, leading to better emotional self-regulation and reduced PTSD symptoms, potentially resulting in lasting symptom relief. Evidence suggests that neurofeedback (NFB) has moderate benefits for reducing PTSD symptoms, along with positive effects on depression and anxiety. These effects were consistent across diverse trauma types and populations. Modulating alpha rhythm appears to be a promising NFB protocol, with observed changes in DMN and SN connectivity correlating with decreased PTSD severity. ADHD Treatment via QEEG-Informed Neurofeedback Treatment Stratification and Predictors of Response: Awaiting Multi-Centre Replication

• 59. Vagal Nerve Stimulation (VNS) VNS aims to modulate the parasympathetic system to counteract the sympathetic response and facilitate rapid memory storage. It enhances memory and neural plasticity, particularly in fear extinction pathways such as the infralimbic prefrontal cortex and basolateral amygdala. In PTSD models, VNS paired with exposure therapy has reversed impaired extinction and prevented fear relapse, indicating robust, lasting effects. [McIntyre, 2018] Stellate Ganglion Block: The stellate ganglion is part of the sympathetic nervous system and is a cluster of nerve cell bodies between the C6 and C7 vertebrae. Since the stellate ganglion is connected to the amygdala, it has been explored as a potential alternative treatment option for PTSD. Stellate ganglion block (SGB) can regulate the autonomic nervous and cerebrovascular systems, dilate blood vessels, and improve circulation; therefore, it is widely used in treating head, neck, and upper limb pain. A stellate ganglion block (SGB) is a procedure involving the injection of a local anaesthetic surrounding the stellate ganglion to inhibit sympathetic outflow to the ipsilateral portion of the head, neck, thorax, and upper extremities. [Blakey et al., 2024] SGB’s benefit in PTSD is that SGB decreases nerve growth factor levels, thus reducing noradrenaline and the hyperaroused state of the sympathetic nervous system present in PTSD. One RCT found benefits, while another showed no significant difference. It is considered an experimental treatment currently. [Bajor et al., 2022] It may also specifically be helpful in patients with PTSD and comorbid head, neck, and upper limb pain. [ Lipov et al, 2009] In a randomised controlled trial, SGB showed the most significant reductions in arousal and reactivity symptoms (e.g., hypervigilance, concentration, and sleep disturbances) and clinician-rated reexperiencing symptoms (e.g., physiological and emotional reactions to trauma). [Blakey et al., 2024] Neuromodulation:

• 60. There is no evidence that rTMS or ECT reduce PTSD symptoms; however, they may be effective in patients with refractory depression and comorbid PTSD. Dual-tDCS, high-frequency rTMS, intermittent theta burst stimulation, and lowfrequency rTMS significantly reduced PTSD symptoms at the treatment endpoint, but effects were not sustained at follow-up. [Liu et al., 2024] No significant difference was observed between active treatments and sham controls. Additionally, synchronized TMS reduced depression symptoms at the endpoint, and dual-tDCS reduced anxiety symptoms at follow-up. Overall, these neuromodulation methods were effective initially but showed limited long-term efficacy. There are case reports of Deep Brain Stimulation (DBS) showing efficacy in PTSD, and trials are underway. [Du et al., 2022] MDMA (3,4-Methylenedioxymethamphetamine): MDMA-assisted psychotherapy is currently considered an experimental treatment for PTSD and should be approached with caution. While some clinical trials have demonstrated potential benefits in treatment-resistant PTSD cases, significant concerns about safety, adverse events, and abuse potential persist. [Yang et al., 2024]. FDA reviews have raised concerns about MDMA’s safety, potential for abuse, and design biases in registration trials, limiting its approval for clinical use. The recent FDA rejection for broader clinical use highlights the need for strict regulation and limited application. Psychedelics and Hallucinogens in Psychiatry – Mechanisms of Action and Clinical Application Other experimental treatments – D-cycloserine (glycine receptor agonist), endocannabinoids, neuropeptides (NPY antagonists, cholecystokinin antagonists, substance P antagonist, and nalmefene (endogenous opioid antagonist)), ketamine, mifepristone and hydrocortisone. Prevention of PTSD:

• 61. Propranolol: In PTSD, reactivated memories become temporarily labile and require stabilisation, which is known as reconsolidation. As PTSD is associated with a hyper-noradrenergic state and β-noradrenergic receptor stimulation has been found to facilitate emotional memory reconsolidation, using a β-noradrenergic receptor antagonist may prevent traumatic memory reconsolidation and thus may help in addressing intrusion symptoms of PTSD. [Roullet et al, 2021] Propranolol administered prior to trauma memory reactivation decreased the severity of PTSD symptoms, reduced physiological responses (e.g., heart rate, skin conductance, blood pressure), and improved cognitive performance in individuals with PTSD. [Young & Butcher, 2020] When used as a preventative measure following trauma, propranolol did not significantly reduce the risk for subsequent PTSD. Hydrocortisone: 30 mg oral hydrocortisone or placebo prior to prolonged exposure (PE) was associated with a greater reduction in total PTSD symptoms in a small study. [Yehuda et al., 2015] According to a systematic review and meta-analysis [Astill Wright et al., 2019] The limited evidence for hydrocortisone and its adverse effects mean it cannot be recommended for routine use, but, it could be considered as a preventative intervention for people with severe physical illness or injury, shortly after a traumatic event, as long as there are no contraindications. Initiating therapy within the ‘golden’ first six hours post-trauma is thought to be crucial to impeding the disruption to memory consolidation that occurs within this period. However, one study showed benefits outside this period ( within 12 hrs) as well. A high-dose IV (100-400 mg single dose) was used in one study in prevention. [Astill Wright et al., 2019] ALGORITHM FOR PHARMACOLOGICAL MANAGEMENT OF PTSD

• 62. This pharmacological algorithm has been modified from the original framework from [Bajor et al.,2022].

• 63. Click to enlarge. Downloadable with a Hub Pro subscription. The modifications incorporate recent scientific insights and practical considerations. Key updates include the addition of specific neurobiological markers such as inflammatory markers (e.g., C-reactive protein), neuroendocrine changes (e.g., cortisol levels), and biomarkers of autonomic dysregulation (e.g., heart rate variability) to guide stage-specific interventions. (See earlier section on PTSD and Inflammation) Additionally, clonidine has been repositioned as a primary early option for managing sleep disturbances, reflecting its broader applicability beyond just prazosin failure or sleep onset issues. Another key modification is the consideration of novel treatments like ketamine and MDMA in treatment-resistant cases. These changes are based on emerging evidence supporting a more personalised and neurobiologically-informed approach, emphasising augmentation strategies with antiinflammatory agents and refined symptom management techniques. The revised algorithm focuses on comprehensive reassessment and a tailored approach to improve PTSD treatment outcomes, aligning with evolving research and clinical practices. Stage 1: Initial Evaluation Confirm Diagnosis of PTSD Conduct comprehensive assessment using DSM-5 criteria. Assess for comorbidities (e.g., substance use, bipolar disorder, depression, dissociation, pregnancy). Integrate neurobiological markers (e.g., inflammation, neuro-hormonal changes) to identify stages and guide treatment decisions. Stage 2: Early Symptom Management Evaluate Sleep Disturbance & Nightmares

• 64. If sleep disturbances or nightmares are present: First-line: Prazosin or clonidine. Clonidine is added for cases where prazosin shows limited efficacy or is poorly tolerated. Clonidine has benefits for sleep onset difficulties, with prazosin showing benefits only for sleep maintenance. Both options address REM sleep disruptions and hyperarousal. If non-response: Add hydroxyzine or trazodone. Trazodone dose : 12.5 mg to 200 mg. The usual starting dose is 50 mg. Hydroxyzine: 25 -100 mg. Monitor Sleep Response If sleep improves, proceed to assess overall PTSD symptoms. If there is no improvement or ongoing sleep issues, consider increasing the dose or switching to alternative agents (e.g., clonidine). Stage 3: Addressing Residual PTSD Symptoms Assess Residual PTSD Symptoms If residual significant PTSD symptoms are present after addressing sleep: Early interventions include psychoeducation, cognitive restructuring, and resilience-building. Initiate SSRIs (e.g., sertraline or paroxetine) or SNRIs (e.g., venlafaxine). Consider anti-inflammatory agents if biomarkers indicate high inflammation. (See Earlier in the section on Anti-Inflammatory Medications) SSRI/SNRI Trial Duration Ensure adequate trial duration (8-12 weeks) with dose optimization.

• 65. Monitor response: If no response, move to the next line of treatment. If partial response without psychosis, continue for a longer duration or consider augmentation. If Partial response with psychosis, augment with antipsychotics (e.g., olanzapine, aripiprazole). Stage 4: Second-Line Strategies for Persistent Symptoms Second SSRI or SNRI Trial If the initial SSRI or SNRI fails, consider switching to an alternative SSRI or SNRI (e.g., venlafaxine). Evaluate response: If no improvement, consider third-line treatments. If partial response, maintain the current regimen and explore additional augmentation options. Third-Line Medications Include options like daytime prazosin or clonidine for persistent hyperarousal. Memantine’s action on the glutamatergic system could help address persistent symptoms, including cognitive impairments, emotional dysregulation, and unresponsive core PTSD symptoms. It can be especially useful for patients with symptoms related to memory dysfunction or anxiety-like behaviour. [Hori et al., 2021]; [Ishikawa et al., 2019]; [Chopra et al., 2011] Consider neurofeedback or rTMS to address persistent emotional dysregulation and attention biases. Stage 5: Treatment-Resistant Cases For cases not responding to three medication trials: Introduce ketamine for rapid symptom relief.

• 66. Consider advanced interventions like stellate ganglion block, reconsolidation therapy, or high-intensity psychotherapy. Memantine’s potential for broader symptom improvement, including cognitive symptoms and mood stabilisation, aligns with the need for more intensive interventions in treatment-resistant PTSD cases. [Ramaswamy et al., 2015] Monitor Neurobiological Markers and Symptom Progression Reassess regularly to identify changes in neurobiological markers, symptom progression, and emerging comorbidities. Adapt treatment based on current stage and neurobiological profile. Stage 6: Augmentation and Personalised Strategies Augmentation Pathways for Persistent Symptoms Based on predominant symptoms: For high inflammation: Consider anti-inflammatory agents. For emotional dysregulation or cognitive issues: Use rTMS or neurofeedback. For psychotic symptoms, Consider olanzapine or aripiprazole augmentation. Psychosocial Interventions and Long-Term Support Integrate supportive psychotherapy, group therapy, and social interventions. Reinforce psychoeducation to enhance resilience and coping. Given its investigational status, MDMA should be considered only for patients with severe, refractory PTSD who have not responded to established interventions and only within controlled clinical trials or compassionate-use frameworks. Alternative interventions, such as ketamine, stellate ganglion block, reconsolidation therapy, and memantine, offer viable options currently. AUSTRALIAN PHARMACOLOGCIAL ALGORITHM FOR THE MANAGEMENT OF PTSD SSRIs are considered first-line pharmacological treatments. Fluoxetine, Sertraline and Paroxetine have the best evidence for efficacy. Amongst SNRIs, Venlafaxine

• 67. has the best evidence. Augmentation of SSRI or quetiapine is recommended in the context of marked agitation. Trazodone 50mg-100mg night, quetiapine or prazosin are recommended as augmentation strategies if insomnia is present. Mirtazapine is recommended as 4th line treatment.

• 68. Click to enlarge. Downloadable with a Hub Pro subscription. PTSD AND COMORBIDITIES

• 69. PTSD and Depression: [Rosen et al., 2020] Residual symptoms like insomnia and hyperarousal often persist in PTSD, overlapping with depression. Combining medications with psychotherapies shows limited benefit for PTSD but improves comorbid depression. Antidepressants may be added to trauma-focused therapies for significant comorbid depression, particularly SSRIs like paroxetine, which show positive outcomes in both PTSD and depressive symptoms. Treating PTSD first can reduce depressive symptoms, but depression-focused treatments do not reduce PTSD. Ketamine has shown promise, reducing hospital stays in comorbid PTSD and depression by 70%. CPT and Prolonged Exposure are primary therapies, with antidepressants added for severe comorbid depression. Future strategies aim for personalized approaches, exploring treatment sequencing, combinations, and biomarkers. PTSD and Substance Use Disorder: Approximately 30-60% of individuals with PTSD also have a co-occurring Substance Use Disorder (SUD), highlighting a significant overlap between these conditions. PTSD and Substance Use Disorder (SUD) comorbidity likely involves overlapping neurobiological mechanisms driven by self-medication and combined psychological and physiological effects of trauma and substance use. [María-Ríos & Morrow, 2020] Integrated treatment combining trauma-focused psychotherapy, like Cognitive Processing Therapy (CPT) or Prolonged Exposure (PE), with medications such as naltrexone for Alcohol Use Disorder (AUD) or buprenorphine for Opioid Use Disorder (OUD) has shown strong support. [Back et al., 2024] Anticonvulsants (e.g., Topiramate, Zonisamide): Topiramate has shown potential for reducing both alcohol use and PTSD symptoms when combined with trauma-focused therapies like Prolonged Exposure (PE). [Batki

• 70. et al., 2014] Ongoing trials are examining the efficacy of topiramate combined with PE to enhance treatment completion and reduce PTSD and alcohol use symptoms. Adrenergic Modulators (e.g., Prazosin, Doxazosin): Clinical trials in veterans with PTSD and AUD have shown mixed results, with both active drugs and placebo conditions leading to improvements in symptoms. [Back et al., 2023] Future studies are focusing on subgroups (e.g., patients with high pretreatment blood pressure or severe withdrawal symptoms) to determine potential benefits. Selective Serotonin Reuptake Inhibitors: While SSRIs are FDA-approved for PTSD, their effects on SUD outcomes are inconsistent. Paroxetine has shown some efficacy in reducing PTSD symptoms, but less impact on substance use outcomes when used alone. They may still be useful as part of combined treatment, particularly for managing depressive symptoms that co-occur with PTSD and SUD. Opioid Use Disorder (OUD) Medications: Buprenorphine and methadone, when combined with PE or other trauma-focused therapies, have shown promise in managing PTSD symptoms in OUD patients. Early findings indicate that trauma-focused psychotherapy can be integrated effectively with OUD medications, helping to reduce trauma symptoms while maintaining addiction recovery. [Peck et al., 2023] Oxytocin: Oxytocin, a neuropeptide with anxiolytic and prosocial effects, is being explored as an adjunct to Cognitive Processing Therapy (CPT) for comorbid PTSD/AUD. In ongoing trials, intranasal oxytocin is administered before therapy sessions to enhance the therapeutic process, potentially improving outcomes for both PTSD and alcohol use. [Horn et al, 2024]. Naltrexone for Alcohol Use Disorder (AUD):

• 71. Naltrexone has demonstrated effectiveness in reducing alcohol use severity when combined with trauma-focused treatments, such as PE or CPT. The “Project Harmony” study found that PE combined with naltrexone produced the best long-term alcohol-related outcomes compared to supportive counselling or placebo combinations. [Hien et al., 2024] Psychedelic-Integrative Therapies (e.g., MDMA): Psychedelic-assisted therapy, particularly with MDMA, is being investigated for its potential to facilitate trauma processing while reducing substance cravings. An Australian study is examining MDMA combined with Concurrent Treatment of PTSD and Substance Use Disorders Using Prolonged Exposure (COPE) therapy for PTSD and AUD, aiming to improve PTSD symptoms and alcohol use outcomes. [Morley, 2024] PTSD and Sleep Disorders The interaction between PTSD and sleep disorders suggests a shared underlying mechanism, primarily driven by noradrenergic dysregulation and REM sleep disruption, creating a self-sustaining cycle of arousal, sleep fragmentation, and impaired emotional processing. [Lancel et al., 2021] Sleep disturbances contribute significantly to the development, maintenance, and severity of PTSD. Common Sleep Disorders: Obstructive Sleep Apnea (OSA) affects 40-90% of individuals with PTSD, leading to frequent oxygen desaturations and arousals, contributing to sleep fragmentation. Insomnia and Nightmares are common, exacerbating hyperarousal and perpetuating a cycle of disturbed sleep and PTSD symptoms. Periodic Limb Movement Disorder (PLMD) is observed in 33% of PTSD patients, causing frequent arousals. Sleep Paralysis and parasomnias, including confusional arousals, night terrors, and REM sleep behaviour disorder-like events, are also prevalent, disrupting both REM and non-REM sleep phases.

• 72. Pathophysiological Mechanisms Linking Sleep Dysfunction and PTSD: Noradrenergic Hyperactivity: Hyperactive projections from the locus coeruleus (LC) play a key role in both PTSD and sleep disturbances, contributing to a state of heightened arousal and disrupted REM sleep. Reciprocal Effects: Trauma-related hyperarousal can worsen OSA by promoting disordered breathing, while untreated OSA may increase the risk of PTSD due to ongoing sympathetic overactivity and sleep disruption. REM Sleep Disruption: Given that many OSA events occur during REM sleep, the ability of the brain to process negative emotions during this phase is likely impaired, reinforcing both PTSD symptoms and sleep dysfunction. Evaluation of Sleep Dysfunction in PTSD: Evaluation should cover trauma-related sleep triggers, circadian rhythm issues (e.g., in shift workers), parasomnias, and OSA. Screening tools like the Nightmare Disorder Index (NDI) and polysomnography (PSG) are helpful for accurate assessment. Non-Pharmacological Interventions: CBT for Insomnia (CBT-I) has the strongest evidence for improving sleep in PTSD. It focuses on sleep hygiene, relaxation training, and cognitive therapy. Imagery Rehearsal Therapy (IRT) is effective for treating nightmares, while exposure to trauma-related triggers can reduce sleep-related anxiety. Weighted blankets and other safety-promoting measures can aid relaxation, while interventions like Continuous Positive Airway Pressure (CPAP) effectively treat OSA. Pharmacological Interventions: [Lancel et al., 2021] Prazosin, an alpha-1 receptor antagonist, is the most supported medication for reducing nightmares and improving sleep. Sedating antipsychotics and antidepressants may help but require monitoring for side effects. Benzodiazepines are discouraged due to their risks, including worsening PTSD symptoms and potential for addiction.

• 73. PTSD and Psychosis: Lifetime PTSD rates are higher in individuals with psychotic disorders (30%) than in the general population (7.8%). The actual rates may be underestimated due to underreporting in patients with serious mental illness. [Hardy & Mueser, 2017] Pathophysiology: The link between trauma, PTSD, and psychosis involves multiple pathways [Hardy & Mueser, 2017] Childhood adversity leading to psychosis Trauma resulting from psychosis or involuntary treatments Trauma-induced psychosis PTSD and re-traumatisation exacerbating psychosis. Shared mechanisms include dissociation, intrusive symptoms like hallucinations and delusions, and negative symptoms such as withdrawal, often overlapping with PTSD’s emotional numbing. Neurobiological, genetic, and symptom differences indicate that PTSD with secondary psychotic features (PTSD-SP) may be a distinct subtype. [Compean & Hamner, 2019] Dysregulation in the stress response and alterations in the dopamine system are thought to contribute to the comorbidity. Treatment: [Compean & Hamner, 2019] Evidence-based psychotherapies such as cognitive processing therapy (CPT), prolonged exposure (PE), and EMDR are recommended for PTSD, including PTSDSP. However, clinicians often hesitate to use them due to concerns of exacerbating psychotic symptoms. Despite concerns, research shows that these therapies do not worsen symptoms and are effective in managing comorbid PTSD and psychosis. Second-generation antipsychotics (SGAs), mainly risperidone and quetiapine, have been explored as adjunctive treatments.

• 74. Risperidone has shown modest efficacy, particularly in reducing psychotic symptoms in PTSD-SP, but the evidence remains limited due to a scarcity of high-quality randomized controlled trials. SSRIs are the first-line treatment for PTSD but may be less effective in cases with comorbid psychosis. PTSD and ADHD: PTSD and ADHD often co-occur, leading to more severe psychiatric symptoms, impaired psychosocial functioning, and complex treatment requirements. [Spencer AE, Faraone SV, Bogucki OE, Pope AL, Uchida M, Milad MR, Spencer TJ, Woodworth KY, Biederman J. Examining the association between posttraumatic stress disorder and attentiondeficit/hyperactivity disorder: a systematic review and meta-analysis. J Clin Psychiatry. 2016 Jan;77(1):72-83]. Neurobiological mechanisms common to both disorders include prefrontal cortical (PFC) dysfunction and dopaminergic dysregulation, which contribute to deficits in attention, impulse control, and emotional regulation. Neurobiology of Attention Deficit Hyperactivity Disorder (ADHD) – A Primer PFC dysfunction disrupts top-down inhibition in both conditions, impairing emotional regulation in PTSD and executive functions in ADHD. Dopaminergic abnormalities also underlie impulsivity and reward processing issues, which are central to ADHD and contribute to PTSD’s hyperarousal and memory alterations. This shared dopaminergic dysfunction could explain why individuals with ADHD may be at an increased risk for developing PTSD following trauma exposure, as dopamine plays a central role in fear conditioning and stress responses. [Spencer et al, 2016]. Clinically, individuals with co-occurring PTSD and ADHD exhibit worse cognitive performance, greater impulsivity, and a higher risk of additional psychiatric comorbidities, such as substance use disorders (SUDs) and depression. [Antshel et al, 2016]. , [El Ayoubi, et al, 2021].

• 75. This combination complicates treatment and often results in poorer outcomes. The familial co-aggregation of the disorders suggests shared genetic risk factors, emphasising the need for early detection and intervention to prevent the worsening of symptoms. [Wendt et al.,2023]. Integrated treatment strategies are crucial, combining trauma-focused therapies with ADHD-specific interventions. Dopaminergic agents like methylphenidate and atomoxetine could be beneficial, given their role in enhancing PFC functioning and managing symptoms of hyperarousal and inattention [Torrisi et al., 2019]. Integrating trauma-focused therapies alongside psychostimulants may offer synergistic benefits by improving fear extinction and reducing symptom relapse. [Houlihan,2011]. Given the greater clinical severity and psychiatric comorbidity associated with this dual diagnosis, a comprehensive, phase-specific treatment plan is essential. Early management of ADHD can help reduce the risk of developing PTSD following trauma, improving overall clinical outcomes. Screening for ADHD among trauma-exposed individuals may enhance the effectiveness of PTSD prevention and treatment efforts. PTSD and Bipolar Disorder (BPAD) Bipolar disorder (BD) and PTSD frequently co-occur, with estimates suggesting that up to 50% of individuals with BD also meet the criteria for comorbid PTSD. [Russell et al., 2024]. This comorbidity is associated with worse clinical outcomes, including more severe depressive and manic symptoms, poorer sleep quality, and increased rates of hospitalisations compared to those with BD alone. Individuals with both disorders often receive sedative medications more frequently, while lithium use is lower, particularly in those with multiple trauma exposures. [Russell et al., 2023].

• 76. Studies indicate that the prevalence of PTSD among bipolar patients is approximately 16%, which is twice the lifetime prevalence in the general population. [Otto et al., 2004]. Contributing risk factors include greater trauma exposure, the presence of additional Axis I disorders, and lower levels of social support and socioeconomic status. Currently, no randomised controlled trials (RCTs) have been conducted specifically for the treatment of comorbid BD and PTSD, and existing evidence is limited to observational studies and open-label trials. Pharmacological management is challenging due to the risk of triggering manic episodes or rapid cycling when using selective serotonin reuptake inhibitors (SSRIs) or other antidepressants. It is recommended to prioritise mood stabilisation before introducing antidepressants to mitigate this risk. [Hendriks & Goossens, 2022]. Studies suggest that lithium response rates are lower in patients with comorbid PTSD, while quetiapine shows some efficacy, although with more severe residual symptoms compared to BD alone. [Russell et al., 2023]. CONCLUSION Posttraumatic Stress Disorder (PTSD) is a complex and heterogeneous disorder characterised by distinct phenotypes arising from alterations in neurocircuits regulating emotion, memory, and reactivity. The condition’s pathophysiology involves structural and functional brain changes in regions such as the amygdala, prefrontal cortex, and hippocampus, contributing to symptoms like intrusions, avoidance, mood disturbances, and hyperarousal. Effective diagnosis of PTSD requires recognition of its heterogeneity and frequent comorbidity with other psychiatric disorders, such as depression, substance use, and psychosis. This necessitates a broad diagnostic approach to avoid misattributing symptoms solely to trauma, which could lead to misdiagnosis and inadequate care.

• 77. The development of PTSD involves complex interactions between pre-trauma vulnerabilities, acute peritraumatic responses, and posttraumatic factors, reflecting a deeper biological adaptation to stress. The disorder’s persistence beyond one month signifies abnormal neurobiological responses rather than a normal adaptation to stress, emphasizing the importance of neurobiological insights for both diagnosis and treatment. Management requires phase-specific and individualised approaches that incorporate trauma-focused psychotherapies, pharmacotherapies, and potential neurobiological interventions. Treatments should target core symptoms and address co-occurring conditions to enhance outcomes. While therapies like neurofeedback, anti-inflammatory agents, and neuromodulation show promise, further research is necessary to determine their roles in treatment-resistant cases. Thus, PTSD is a multidimensional disorder that requires an integrated, evidence-based approach. Advances in personalised medicine and emerging interventions offer promising pathways for more effective treatment, emphasising the need for ongoing research to enhance recovery and functional outcomes. Get Serious About Psychiatry Learning Our courses offer practical knowledge and clinical expertise at exceptional value, plus CME & CPD points. References Yehuda, R., Hoge, C. W., McFarlane, A. C., Vermetten, E., Lanius, R. A., Nievergelt, C. M., Hobfoll, S. E., Koenen, K. C., Neylan, T. C., & Hyman, S. E. (2015). Post-traumatic stress disorder. Nature reviews. Disease primers, 1, 15057.

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• 87. Hien, D. A., Papini, S., Saavedra, L. M., Bauer, A. G., Ruglass, L. M., Ebrahimi, C. T., Fitzpatrick, S., López-Castro, T., Norman, S. B., Killeen, T. K., Back, S. E., & MorganLópez, A. A. (2024). Project harmony: A systematic review and network meta-analysis of psychotherapy and pharmacologic trials for comorbid posttraumatic stress, alcohol, and other drug use disorders. Psychological Bulletin, 150(3), 319–353. El Ayoubi, H., Brunault, P., Barrault, S., Maugé, D., Baudin, G., Ballon, N., & El-Hage, W. (2021). Posttraumatic Stress Disorder Is Highly Comorbid With Adult ADHD in Alcohol Use Disorder Inpatients. Journal of Attention Disorders, 25(11), 1594-1602 Wendt FR, Garcia-Argibay M, Cabrera-Mendoza B, Valdimarsdóttir UA, Gelernter J, Stein MB, Nivard MG, Maihofer AX; Post-Traumatic Stress Disorder Working Group of the Psychiatric Genomics Consortium; Nievergelt CM, Larsson H, Mattheisen M, Polimanti R, Meier SM. The Relationship of Attention-Deficit/Hyperactivity Disorder With Posttraumatic Stress Disorder: A Two-Sample Mendelian Randomization and Population-Based Sibling Comparison Study. Biol Psychiatry. 2023 Feb 15;93(4):362-369 Russell, S. E., Wrobel, A. L., Lotfaliany, M., Ashton, M. M., Kaur, R., Yocum, A. K., … & Turner, A. (2024). Trauma and comorbid post-traumatic stress disorder in people with bipolar disorder participating in the Heinz C. Prechter Longitudinal Study. Journal of affective disorders, 348, 275-282 Advances in Understanding Posttraumatic Stress Disorder (PTSD): A Comprehensive Review of Pathophysiology, Diagnosis, and Management sanil.rege@gmail.com October 30, 2024 5:56 pm No Comments This article explores the latest advances in understanding Posttraumatic Stress Disorder (PTSD), highlighting its complexity as a heterogeneous condition marked by neurocircuit alterations affecting emotion, memory, and arousal regulation.

• 88. It provides a comprehensive overview of the disorder’s pathophysiology, diagnostic complexities, and evidence-based management, emphasising the importance of personalised, phase-specific interventions. PTSD arises from the direct or indirect experience of a life-threatening or distressing event, often leaving an enduring psychological impact marked by physical, cognitive, emotional, and behavioural changes. These traumatic events trigger intense feelings of fear, helplessness, and horror, setting the stage for the development of chronic symptoms. Classified in the DSM-5 as a trauma and stressor-related disorder, PTSD is characterised by intrusive memories, hypervigilance, emotional numbness, and efforts to avoid reminders of the trauma. Symptoms often persist beyond the original context, reflecting a failure to update safety signals and perpetuating a sense of danger and unpredictability. Understanding the neurobiology of PTSD is crucial for exploring how trauma imprints on the brain and behaviour. Across different cultures and historical periods, similar symptom patterns such as flashbacks, nightmares, and heightened startle responses indicate shared neurobiological foundations. Research into PTSD’s development reveals a complex interaction of pre-trauma vulnerabilities, immediate peritraumatic responses, and posttraumatic factors that influence both chronicity and recovery. By understanding these mechanisms-spanning molecular pathways, neurocircuit disruptions, and changes in neurocognitive, emotional, and interpersonal processes, clinicians can better predict, diagnose, and treat this disorder. Psychological trauma can be classified into 4 clusters of symptoms. These include: Intrusion symptoms– Flashbacks, nightmares, and intrusive thoughts Avoidance – Avoidance of stimuli associated with trauma

• 89. Negative Alterations in Cognitions and Mood associated with the traumatic event (s) – difficulty recalling important aspects of trauma, emotional detachment, etc. Hyperarousal – Hypervigilance, Insomnia, agitation, irritability, impulsivity, and anger For some, however, the syndrome persists, and this is termed post-traumatic stress disorder (PTSD). A PTSD diagnosis was originally considered a normal response to an extreme situation; however, the presence of symptoms for an extended period of time beyond one month is indicative of an abnormal adaptation in the brain. The prevalence of PTSD varies across countries. It occurs in 5-10% of the population and has a 2:1 female-to-male ratio. The gender bias may be a result of a combination of a greater propensity to lifetime violence exposure and genetic vulnerability (variation in the ADCYAP1R1 (pituitary receptor) gene). [Yehuda et al., 2015] In military populations, the risk is more significant. For example, 10 years after the Vietnam war the rates of current PTSD went up to 28% in those who had experienced combat exposure. A recent analysis showed that 40 years after the end of the war, 11% of Vietnam veterans are experiencing PTSD symptoms. [Yehuda et al., 2015] In civilian population samples, the rates vary from 0.2%-3.8%. A number of factors such as social supports, trauma type, and severity affect prevalence. We covered Complex PTSD in a separate article. Achieve clinical excellence in Adult ADHD Join Academy by Psych Scene and get instant access to interactive, cutting-edge courses on ADHD. Over 40 hours of learning that earn CME/CE/CPD points. PREVALENCE OF PTSD content The prevalence of PTSD varies across countries. It occurs in 5-10% of the population and has a 2:1 female-to-male ratio. The gender bias may be a result of a

• 90. combination of a greater propensity to lifetime violence exposure and genetic vulnerability (variation in the ADCYAP1R1 (pituitary receptor) gene). [Yehuda et al., 2015] In military populations, the risk is more significant. In a study of 69,000 adults globally, 70% experienced at least one traumatic event, and 30.5% faced four or more events. [Benjet et al., 2016] Most trauma survivors do not develop PTSD; they experience transient symptoms, which may intensify at specific times (e.g., anniversaries), but generally maintain good functioning. Trauma can lead to other psychiatric disorders, including major depression and substance misuse, not just PTSD. The National Comorbidity Survey estimated lifetime PTSD prevalence at 6.8% among U.S. adults, with current prevalence at 3.5%. [Kessler et al., 2005] PTSD prevalence is higher among women than men, with lifetime rates of 9.7% in women versus 3.6% in men; past-year rates are 5.2% in women versus 1.8% in men. [Shalev et al., 2024] Among Vietnam veterans, lifetime PTSD prevalence was 30.9% for men and 26.9% for women; 15–18 years post-war, current rates were 15.2% for men and 8.1% for women. Longitudinal studies of Vietnam veterans found that 4.5% had current PTSD 40 years after the war, with 17% having lifetime war-zone PTSD. [Marmar et al., 2015] Symptoms of PTSD generally decrease within a year post-trauma, with initial symptom rates dropping significantly over time, as seen in rape and nonsexual assault survivors. Median PTSD remission time is 36 months for those who seek help and 64 months for those who do not; one-third of cases remain chronic. [Shalev et al., 2024] Delayed-onset PTSD is rare; it often involves worsening of existing symptoms or delayed help-seeking, as seen in studies of combat veterans. [Shalev et al., 2024] RISK FACTORS FOR PTSD content Demographic Factors [Shalev et al., 2024] Female gender - twice as likely to develop PTSD Younger age at trauma

• 91. Race: In the U.S., African Americans, Latino Americans, and Native Americans exhibit the highest rates of PTSD, while Asian Americans have the lowest prevalence. [Asnaani & Hall-Clark, 2017]. Indigenous Australians face a higher likelihood of experiencing traumatic events and developing PTSD compared to other Australians. [Nasir et al., 2021] Lower education levels Personal History Previous trauma (both adult and childhood) Psychological adjustment issues Family history of psychopathology. Attachment style and personality traits like neuroticism and introversion Trauma Severity Higher trauma severity, perceived life threat, emotional distress, and dissociation during trauma. Social Support Lack of social support following trauma. Additional Stressors Experiencing further life stressors after the traumatic event raises PTSD risk Combat-Related Factors For combat-related PTSD, risk factors include lower education, non-officer status, longer deployments, adverse life events, and pre-existing psychological issues. Interpersonal Violence Exposure to interpersonal violence or multiple traumatic events significantly elevates the risk of PTSD. Amygdala Hyperresponsivity

• 92. Heightened amygdala activation in response to ambiguous facial expressions (e.g., surprised or neutral) may serve as a familial vulnerability marker for PTSD. [Hinojosa et al., 2022] Genetic Vulnerability: [Shalev et al., 2024] Approximately 30–40% of PTSD risk is heritable, with environmental factors like trauma type and individual differences in fear regulation playing critical roles. [Ressler et al., 2022] Variants in genes such as FKBP5, PACAP1, COMT, DRD2, and RGS2 are linked to PTSD risk, particularly in those with a history of childhood trauma. [Nievergelt et al., 2018] The s/s genotype of the serotonin transporter gene (5-HTTLPR) combined with childhood adversity increases PTSD risk. [Uher et al., 2011] Single-nucleotide polymorphism on chromosome 4 and an estrogen response element on ADCYAP1R1 are implicated. Specific Gene Associations: CRFR1 and PAC1R: Variations in genes encoding CRFR1 and PAC1R are linked to increased hyperarousal, higher PTSD symptoms, and heightened physiological responses to stress. Both genes are prominently expressed in PTSD-related brain areas (amygdala, bed nucleus of the stria terminalis, medial prefrontal cortex), influencing fear and hyperarousal differently in men and women. [Ressler et al., 2022] FKBP5 Pathway: FKBP5, a key regulator of the cellular glucocorticoid response, is associated with PTSD risk, especially among those with childhood trauma exposure. It influences PTSD symptom type and severity, neural activity, and startle responses, with increased FKBP5 expression found in the brains of individuals with PTSD. [Ressler et al., 2022] Epigenetic Changes: [Shalev et al., 2024]

• 93. In PTSD, epigenetic modifications adjust gene promoter activity, altering gene expression without changing DNA sequence. Reduced methylation of the glucocorticoid receptor gene suggests altered stress regulation. Unique DNA methylation patterns, with unmethylated immune-related genes and increased overall methylation. Changes in de novo methylation genes, like DNMT3B and 3L, indicate adaptive epigenetic shifts. In rodents, trauma decreases BDNF expression via reduced histone acetylation, while fear extinction increases acetylation, promoting recovery. Successful PTSD treatment correlates with changes in DNA methylation at specific regions, showing that epigenetic shifts can be reversed. [Vinkers et al., 2021], [Bishop et al., 2018], [Yehuda et al., 2013] Epigenetic Mechanisms in Psychiatric Disorders – Major Depression, Psychosis and Addiction Trauma outcomes vary across individuals, and this appears to be dependent on genetic susceptibility factors, history of prior psychological trauma, or an additional physical injury at the time of the traumatic event, such as traumatic brain injury (TBI). DIAGNOSTIC CRITERIA FOR PTSD content The Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5) recognises several criteria for a PTSD diagnosis. The PTSD criteria are as follows: 1.Exposure to stressor The individual was either directly or indirectly (witnessing, learning, or exposure to aversive details) exposed to trauma. 2. Intrusion symptoms (one or more required) The trauma is persistently re-experienced via recurrent memories, nightmares, flashbacks, psychological distress, or physiological reactivity to traumatic reminders. 3. Persistent avoidance (one or more required) Avoidance of trauma-related stressors: recurrent trauma-related thoughts or environmental reminders such as people, activities, and places that act as visual reminders. 4. Negative alterations in cognition and mood (two or more required) Inability to recall key features, persistent (and often distorted) negative beliefs and expectations about oneself or the world, persistent distorted blame of self or others, persistent negative traumarelated emotions, markedly diminished interest in pre-traumatic activities, feeling alienated from others and constricted affect (persistent inability to experience positive emotions). 5. Alterations in arousal and reactivity (two or more required) Disturbances to arousal

• 94. and reactivity that began, or worsened, after the trauma are characterised by aggression, self-destructive or reckless behaviour, hyper-vigilance, exaggerated startle response, and difficulty concentrating or sleeping. 6. Duration More than one month. 7. Functional significance Trauma-related symptoms must cause psychological, social, or functional impairment. Exclusion Trauma-related symptoms cannot be attributed to medications or substance abuse. The ICD-11 PTSD diagnosis is similar to the DSM-5 but more narrow, focusing on traditional fear circuitry symptoms such as re-experiencing, avoidance, and hypervigilance. [Burback et al., 2024] The dissociative subtype of PTSD (PTSD-DT) and Complex PTSD (CPTSD), recently included in the DSM-5 and ICD-11, highlight distinct clinical presentations within PTSD characterised by significant complexity. Both conditions are closely linked to chronic trauma, particularly early childhood trauma and neglect, and are marked by persistent dissociative symptoms. These subsets tend to show a heavier trauma burden and a more severe and prolonged course compared to typical PTSD, with

• 95. higher rates of suicidal ideation, anxiety, depression, and comorbid BPD. [Burback et al., 2024] We have covered the differences between PTSD, Borderline Personality Disorder (BPD) and CPTSD in this article. UNDERSTANDING THE NEUROBIOLOGY OF FEAR AND ANXIETY: FOUNDATIONS FOR PTSD PATHOPHYSIOLOGY content Elucidating the neurobiology of fear and threat processing is essential for understanding the link between trauma and symptoms of PTSD. Fear processing circuits, including the amygdala, hippocampus, and medial prefrontal cortex, are well-studied across species and provide a basis for understanding PTSD’s manifestations. Processes like trauma memory encoding, consolidation, and extinction, critical to PTSD's development, rely on synaptic plasticity and memory systems. The Neuroscience of Emotions: Clinical Relevance for Understanding Depression, Anxiety, and Addiction THE ROLE OF THE AMYGDALA content The amygdala is central to fear processing, acting as a hub for detecting and responding to threatening stimuli. [Li et al., 2023]

• 96. The amygdala integrates sensory information to generate rapid, often reflexive responses, mediated through connections to the hypothalamus and brainstem structures like the periaqueductal gray (PAG). The PAG orchestrates defensive behaviours such as freezing or fleeing, characteristic responses to acute fear. In contrast, anxiety involves more sustained neural activity, primarily engaging the extended amygdala, which includes the bed nucleus of the stria terminalis (BNST). The BNST has been implicated in processing uncertain or diffuse threats, contributing to anxiety's prolonged, anticipatory nature.The prefrontal cortex (PFC), particularly the medial PFC (mPFC), modulates fear and anxiety by exerting top-down control over the amygdala and BNST, facilitating threat appraisal and regulatory mechanisms that can suppress or amplify emotional responses. NEUROTRANSMITTER SYSTEMS IN FEAR AND ANXIETY content GABA: GABAergic inhibition in the amygdala plays a crucial role in reducing fear responses, while the loss of GABAergic tone is associated with heightened anxiety. [Grogans et al., 2023] Glutamate: Glutamate, the principal excitatory neurotransmitter, facilitates rapid communication between the amygdala and other regions, driving immediate fear responses and modulating sustained anxiety through BNST activity. [Li et al., 2023] Serotonin: Serotonin has a more nuanced role, with its impact on fear and anxiety being highly context-dependent. [Bocchio et al., 2016] It is involved in both dampening and enhancing threat responses, influenced by the receptor subtype and neural circuit involved. Serotonin modulates amygdala function via 5-HT receptors,

• 97. impacting fear processing and emotional memory encoding. [Vitalis & Verney, 2018] In the amygdala, 5-HT2A/2C receptors enhance fear conditioning, while 5-HT1A receptors facilitate extinction. Serotonin also modulates the hippocampus and mPFC via volume transmission, maintaining homeostasis. For instance, serotonin's action in the dorsal raphe nucleus (DR / DRN) can mitigate anxiety, while its role in other pathways may heighten vigilance under perceived threat. [Bocchio et al., 2016] Acetylcholine: Basal forebrain cholinergic signalling, primarily from the nucleus basalis of Meynert (NBM) and the horizontal limb of the diagonal band of Broca (HDB), plays a crucial role in fear regulation within the basolateral amygdala (BLA). These pathways enhance the strength and persistence of fear memories, with NBM projections specifically modulating fear conditioning and extinction through nicotinic receptor activation. [Crimmins et al., 2023] Dopamine (DA) Dopamine (DA) serves as a central modulator of both fear extinction and aversive learning, impacting multiple brain circuits involved in anxiety and threat processing. In the amygdala, DA projections to the BLA encode the salience of stimuli, mediating associative learning. [Zafiri & Duvarci, 2022] DA inputs from the ventral tegmental area (VTA) and periaqueductal gray (PAG)/dorsal raphe (DR) target the central amygdala (CEA), with PAG/DR inputs driving associative aversive learning and VTA inputs facilitating fear discrimination. In the mPFC, VTA-derived DA modulates conditioned fear expression and biases behaviour toward aversion, while its role in striatal subregions like the ventral nucleus accumbens (NAc) and tail of the striatum (TS) involves encoding motivational salience and mediating threat avoidance, respectively. DA plays a crucial role in fear extinction by influencing the acquisition and consolidation of extinction memories. Originating from midbrain structures like the VTA and substantia nigra (SN), DA neurons project to the amygdala and mPFC, key regions in fear regulation. DA signalling, particularly through D1-type receptors, enhances the learning and retention of extinction when administered before or after extinction training. Recent findings suggest that fear extinction may engage the brain's reward circuits, positioning DA as a mediator of fear suppression and an appetitive learning process within the amygdala and mPFC. [SalinasHernández & Duvarci, 2021]

• 98. Noradrenaline (NA): Noradrenaline, released from the locus coeruleus, is integral to the arousal component of fear and anxiety, increasing sensory sensitivity and attention towards potential threats. The locus coeruleus-noradrenaline (LC-NA) system is pivotal in regulating fear learning, memory, and extinction, modulating these processes based on arousal levels. During high stress, LC-NA amplifies amygdala-driven fear learning while dampening prefrontal control, resulting in stronger aversive memories. In contrast, under lower arousal, LC-NA enhances prefrontal inhibition of the amygdala, supporting fear extinction. This relationship follows an "inverted-U" function, where optimal arousal improves learning while extreme arousal disrupts it. [Bierwirth & Stockhorst, 2022] Additionally, NA’s role in the hippocampus, due to dense adrenoceptor expression, facilitates contextual fear memory formation. Interactions between LC, amygdala, and hypothalamus—mediated by corticotropin-releasing hormone (CRF) and NA—further intensify fear conditioning and emotional memory encoding. Increased noradrenergic arousal contributes to deficits in fear extinction, underscoring mechanisms critical to PTSD. [Giustino & Maren, 2018]

• 99. PHYSIOLOGICAL RESPONSES IN FEAR AND ANXIETY content The physiological responses to stress exhibit diverse temporal dynamics, reflecting the complexity of the hypothalamic-pituitary-adrenal (HPA) axis and its broader implications. Fear and anxiety both trigger sympathetic nervous system activation, manifesting as increased heart rate, pupil dilation, and other autonomic changes that prepare the body for immediate action. [Godoy et al., 2018] Cortisol release is central to these responses, but its timing varies. Rapid (Acute) Cortisol Response: Initiated within seconds to minutes, acute cortisol release, part of the immediate stress response, involves activating the sympathetic nervous system, leading to rapid physiological changes (e.g., increased heart rate, pupil dilation). This phase is characterized by the modulation of limbic-cortical circuits, enhancing neural excitability in areas like the amygdala and hippocampus, which are crucial for fear and threat processing. [Joëls et al., 2012] Such acute cortisol responses facilitate immediate adaptation and promote the encoding of stressful experiences, aiding in learning and memory formation. [Bains et al., 2015] Delayed (Prolonged) Cortisol Response: Occurs hours after initial stressor exposure and primarily affects synaptic plasticity in limbic-cortical structures. This phase can impair cognitive functions, alter synaptic

• 100. plasticity (e.g., long-term potentiation and depression), and maintain neural excitability beyond acute responses. These delayed cortisol effects contribute to more sustained HPA activation, typical of anxiety states, and modulate the encoding and consolidation of longer-term memories. [Joëls et al., 2012] Prolonged or chronic stress disrupts these mechanisms, resulting in structural changes like hippocampal atrophy and amygdala hypertrophy, leading to anxiety and cognitive deficits. Early-life stress exerts enduring effects, increasing vulnerability to psychiatric disorders later in life. [Godoy et al., 2018] THE PATHOPHYSIOLOGY OF PTSD content The neurobiology of PTSD is complex and involves neuroendocrine, neurochemical and neuroanatomical changes in neural networks. 1. Fear Conditioning and Extinction: Core Circuits The amygdala, hippocampus, and mPFC form the core network for fear conditioning, involving acquisition, consolidation, and extinction of fear responses. [Ressler et al., 2022] Amygdala’s basolateral nucleus processes sensory inputs and links them to aversive stimuli, forming fear memories. These memories consolidate through NMDA receptor activation, BDNF, and calcium-dependent plasticity, leading to structural changes. Overactivity in the amygdala’s central nucleus triggers downstream regions like the hypothalamus, LC, and PAG, driving physiological stress responses, including increased heart rate and activation of the HPA axis. In PTSD, amygdala hyperactivity persists due to inadequate inhibition from the mPFC, resulting in heightened responses to conditioned stimuli. Structural MRI studies confirm alterations in these circuits, with reduced hippocampal and medial prefrontal volumes correlating with symptom severity. In PTSD, a decreased PFC volume correlates with symptom severity due to decreased inhibitory control over the amygdalar stress response. 2. Role of the Amygdala in Threat Processing and PTSD Symptoms

• 101. The amygdala plays a central role in acquiring fear responses and mediating both overconsolidation and extinction failures in PTSD. Heightened amygdala activity persists due to weakened prefrontal inhibition, contributing to hypervigilance, intense physiological responses, and difficulty distinguishing between safe and threatening cues. This contributes to startle responses and persistent reactivity to trauma-related stimuli. [Shalev et al., 2024] Monoaminergic systems, including serotonin, norepinephrine, and dopamine, influence these responses by modulating the consolidation of threat associations, potentially leading to threat overgeneralisation. Structural abnormalities within the amygdala, including increased glutamate transmission and NMDA receptor activity, are linked to pathological memory consolidation and a hyperresponsive reaction to subliminal threats. Structural MRI analysis has revealed pathological damage to the amygdala, which was associated with a hyper-responsive reaction to subliminally threatening cues. [Van Rooij et al., 2015] 3. Medial Prefrontal Cortex and Hippocampal Regulation The mPFC (specifically the vmPFC) regulates fear responses by inhibiting the amygdala and modulating distress. In PTSD, decreased mPFC activity and compromised integrity of the uncinate fasciculus impair this regulatory function, contributing to the persistence of fear and avoidance behaviours. [Shalev et al., 2024] The hippocampus is crucial for encoding fear memories, contextual processing, and regulating amygdala activation. Structural changes, like reduced hippocampal volume, are evident in PTSD and may be due to cortisol-induced neurotoxicity, impairing extinction learning. [Blum et al., 2019] Neuroimaging shows that reduced mPFC and hippocampal activation correlate with symptom severity, reflecting deficits in the ability to suppress fear and transition to recognising safety cues. [Hinojosa et al., 2024] 4. Threat and Salience Detection | Emotional Regulation Circuits The amygdala, dorsal anterior cingulate cortex (dACC), and insula are key to detecting and evaluating threat salience.

• 102. The PFC, in conjunction with the hippocampus, manages emotion regulation by assessing and updating safety cues. In PTSD, overactivity in the amygdala and insula, coupled with reduced PFC activity, impairs the discrimination of safe cues, leading to sustained hyperarousal and reactivity. Decreased frontal cortex and ACC volumes are found in patients with PTSD. 5. Fear-On, Fear-Off, and APPT-On Circuits The amygdala contains three primary circuits associated with different emotional responses. [Ressler et al., 2022] 1. Fear-On circuits: Trigger and sustain fear responses Increase Anxiety Mediated by factors like CRF, PACAP, and TAC2. 2. Fear-Off circuits Inhibit fear responses Fear Extinction Reduce anxiety. 3. APPT-On Circuits: Appetitive (Appetitive) and reward-related responses Regulate fear processing. In PTSD, there is often an overactivation of Fear-On circuits and a concurrent suppression of Fear-Off circuits, leading to persistent fear responses. This imbalance underlies many of the anxiety-related symptoms of PTSD, such as hyperarousal and intrusive thoughts. Moreover, dysregulation of APPT-On circuits can contribute to depression-like symptoms, including anhedonia and avolition, which are common comorbid features of PTSD. 6. Executive Control, Memory, and Attention Dysregulation PTSD-associated symptoms, such as impaired concentration and memory, are linked to dysfunctions in the dACC and frontoparietal attentional networks. These networks are responsible for working memory, response inhibition, and performance monitoring.

• 103. Dysregulated connectivity between these networks and the default mode network (DMN) impedes the ability to disengage from trauma-related stimuli, affecting attention regulation and internal state management. [Jagger-Rickels et al., 2022] 7. Contextual Processing and Appraisal in PTSD The inability to transition from a threat-focused state to recognising safety is a hallmark of PTSD. The vmPFC, hippocampus, and thalamus are central to this process, which relies on adrenergic regulation, especially during sleep. In PTSD, decreased vmPFC activity impairs extinction recall and contextual learning, leading to persistent hypervigilance and difficulties updating safety cues. [Liberzon & Abelson, 2016] Neuroendocrine Aspects in PTSD: 1. Hypothalamic-Pituitary-Adrenal (HPA) Axis Dysregulation [Lawrence & Scofield, 2024] The HPA axis is the primary stress-response system, initiating in the hypothalamus with the secretion of corticotropin-releasing hormone (CRH) from paraventricular neurons (PVN). This stimulates the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary, leading to the release of glucocorticoids (e.g., cortisol) from the adrenal cortex. In PTSD, there is altered cortisol signalling due to increased glucocorticoid receptor sensitivity, resulting in enhanced negative feedback and blunted cortisol responses to stress. This leads to reduced cortisol levels during stress exposure, which impairs normal HPA functioning. [Yehuda et al., 2015], [Sherin and Nemeroff, 2011] The diminished cortisol response contributes to persistent adrenergic hyperactivation, as the usual role of cortisol in dampening the adrenergic system is compromised. As a result, the adrenergic response remains heightened, promoting fear conditioning and intensifying alarm responses during trauma recall. [Zohar et al., 2011] Evidence suggests that low cortisol levels at the time of trauma may predict the development of PTSD, making hypocortisolemia a potential risk factor. This

• 104. observation supports the hypothesis that early intervention with high-dose hydrocortisone post-trauma may prevent PTSD development. [Zohar et al., 2011] 2. Interaction Between the HPA Axis, Hippocampus, and Prefrontal Cortex The hippocampus and mPFC typically exert inhibitory control over the HPA axis. In PTSD, structural and functional deficits in these regions weaken this regulatory effect, contributing to the abnormal HPA feedback observed. The hippocampus, particularly vulnerable to prolonged cortisol exposure, exhibits impaired neurogenesis and reduced plasticity under sustained stress, which is commonly observed in PTSD patients. [Yehuda et al., 2015] This correlates with reduced hippocampal volume, as cortisol-induced damage impairs both memory processing and contextual learning of safety cues, perpetuating fear responses. The mPFC, which also modulates HPA activity, shows decreased volume and reduced connectivity with the amygdala in PTSD, contributing to its impaired ability to regulate stress responses. [Sherin and Nemeroff, 2011] 3. Sympathetic Nervous System and Adrenergic Overactivation In PTSD, the sympathetic nervous system plays a central role due to diminished cortisol responses that fail to adequately counteract adrenergic activity.

• 105. The persistent adrenergic hyperactivation drives chronic symptoms like hypervigilance, heightened startle responses, and sustained anxiety. [Yehuda et al., 2015] Elevated levels of CRH in PTSD lead to blunted ACTH responses at the anterior pituitary due to the down-regulation of CRH receptors a compensatory mechanism driven by excessive CRH secretion. This dysfunction highlights a fundamental dysregulation in neuroendocrine signalling within PTSD, resulting in a persistent state of threat readiness. [Sherin and Nemeroff, 2011] 4. Genetic Contributions to HPA Axis Dysregulation in PTSD Two key genes implicated in the neuroendocrine dysregulation of PTSD are: 1. NR3C1 encodes the glucocorticoid receptor, which influences receptor sensitivity and feedback mechanisms. 2. FKBP5 is involved in immunoregulation and modulating glucocorticoid receptor availability. Alterations in FKBP5 expression have been linked to impaired HPA feedback and altered stress responses in PTSD. [Zohar et al, 2011] Genetic variants affecting these genes can predispose individuals to abnormal glucocorticoid signalling, contributing to hypocortisolemia and the risk of developing PTSD following trauma exposure. 5. Implications for PTSD Treatment and Prevention The neuroendocrine profile in PTSD suggests that treatments targeting glucocorticoid signalling may offer therapeutic benefits. For instance, high-dose hydrocortisone administration soon after trauma exposure has shown promise in reducing PTSD risk, likely by normalizing HPA function and reducing subsequent adrenergic hyperactivation. [Zohar et al., 2011] Future interventions could explore genetic screening for vulnerabilities in NR3C1 and FKBP5, potentially identifying individuals at higher risk and guiding early, targeted treatments to prevent PTSD development.

• 106. Neurotransmitter Roles in PTSD: [Yehuda et al., 2015], [Sherin and Nemeroff, 2011] Serotonin: Altered 5-HT transmission in PTSD includes decreased serum 5-HT, altered 5-HT reuptake, and receptor changes, contributing to symptoms like hypervigilance, impulsivity, and intrusive memories. Chronic stress upregulates 5-HT2 and downregulates 5-HT1A receptors, which correlate with anxiety and difficulty in fear extinction. Decreased serotonin transmission in the dorsal and median raphe is related to hypervigilance, increased aggression, and impulsivity, as well as the enhanced formation and resilience of intrusive memories, providing a role for SSRIs in the treatment of PTSD. 3,4-Methylenedioxymethamphetamine (MDMA) is being studied in the treatment of PTSD as it increases serotonin levels. [Sessa, 2017] The serotonin (5-HT) system influences both PTSD risk and symptom severity. Agents like meta-chlorophenylpiperazine (mCPP), which modulate serotonin receptors, can trigger anxiety, panic attacks, and other PTSD symptoms. While selective serotonin reuptake inhibitors (SSRIs) are effective in managing PTSD symptoms, they do not appear to prevent PTSD when administered immediately post-trauma, highlighting the complex role of serotonin in PTSD development.

• 107. Noradrenaline: In PTSD, there is increased noradrenaline transmission in networks that connect the locus coeruleus to the amygdala and hypothalamus (the noradrenergic feed-forward circuit). The enhanced NA release is associated with increased fear conditioning, enhanced encoding of emotional memories, and increased arousal and vigilance. For example, yohimbine, an α2-adrenergic receptor antagonist, increases NA release, inducing flashbacks and increased autonomic responses in patients with PTSD. Along the same lines, propranolol administration (β2-adrenergic antagonist) after exposure to trauma can reduce PTSD symptom severity and reactivity to trauma cues. Dopamine Dopamine is implicated in the regulation of fear conditioning and anxiety. In addition, in individuals with PTSD, there is a genetic component associated with dopamine metabolism that governs whether an individual develops PTSD and what symptoms they may display. Hypodopaminergia (due to genetic or epigenetic effects) is associated with an increased risk of developing PTSD. Combat stress responses have shown significant elevations of dopamine release (100 times above the resting state). This dopamine depletion, combined with trait hypodopaminergia, is postulated in the pathogenesis of PTSD. Hypodomainergia related to reward may also be linked to an increased risk of substance use disorders. [Blum et al., 2019] Dopamine release in the amygdala contributes to both unconditioned and conditioned stress responses. It can suppress prefrontal projections to the BLA, diminishing inhibitory control over fear responses and promoting hypervigilance. [Torrisi et al., 2019] Dopamine dysregulation is also evident in reward signalling within the NAc, which is often reduced in PTSD, particularly when comorbid with depression. Mesolimbic DA pathways, central to reward-seeking behaviour, are disrupted in PTSD, contributing to anhedonia and emotional numbing due to altered reward processing.

• 108. Increased striatal dopamine transporter (DAT) density observed in PTSD suggests an aberrant DA-dependent reward system, contrasting with reduced DAT density in major depressive disorder (MDD) despite high comorbidity. PTSD is associated with hypoactivation of the NAc and PFC during reward processing, linking DAergic dysfunction to impaired decision-making. [Torrisi et al., 2019] Dopaminergic fibres from the ventral periaqueductal gray (vPAG) and DRN target the central amygdala (CEA), reinforcing fear memory through aversive prediction error signalling. [Torrisi et al., 2019] Dysregulation of the vPAG/DR-CEA circuitry, combined with a DA-related failure of PFC inhibition over the hyperactive CEA, may contribute to maladaptive fear memory formation in PTSD. DA systems may have therapeutic potential in PTSD, particularly by enhancing PFC activity to restore inhibitory control over limbic regions, reducing hyperarousal and intrusive symptoms. [Torrisi et al., 2019] Reactivating the PFC through increased DA signalling can promote fear extinction and resilience against PTSD. Others Glutamate (excitatory) release via the NMDA receptors is involved in synaptic plasticity, learning and memory. GABA (inhibitory) release mediating anti-anxiety effects. Proinflammatory cytokines are involved in neuroinflammation. Endocannabinoids: Endocannabinoids (anandamide, 2-arachidonoylglycerol) mediate memory consolidation via CB1 receptors. In PTSD, the endocannabinoid (eCB) deficiency hypothesis suggests that stress exposure diminishes eCB signalling, particularly anandamide (AEA) and 2-AG, in cortico-limbic areas, leading to amygdala hyperactivity, reduced medial prefrontal cortex (mPFC) activity, and impaired stress regulation. This is especially relevant for individuals with emotion undermodulation. Pharmacological enhancement of eCB signalling can mitigate PTSD symptoms by normalising amygdala and mPFC function, reducing anxiety, suppressing traumatic

• 109. memory recall, enhancing extinction, dampening inflammation, and improving sleep by decreasing REM sleep and arousal. [Hill et al., 2018] Medicinal Cannabis – Psychopharmacology and Clinical Application Neurosteroids (allopregnanolone) have an inhibitory effect on glucocorticoid and NA signalling. [Rasmusson et al., 2017] Neurosteroids such as allopregnanolone and pregnanolone enhance GABAergic signalling, offering neuroprotective benefits by increasing myelination and decreasing neuronal apoptosis. Lower levels of these neurosteroids have been associated with higher PTSD symptoms. Neurosteroids in Psychiatry – Pharmacology | Mechanisms of Action | Clinical Application Neuropeptides (neuropeptide Y, enkephalin endorphins, BDNF and DHEA) Dehydroepiandrosterone (DHEA), a precursor of androgens, is secreted alongside cortisol in response to ACTH stimulation. DHEA antagonizes GABA receptors while facilitating NMDA receptor function, supporting neurocognitive resilience. [van Zuiden et al., 2017] Higher DHEA levels during stress may protect against the negative outcomes associated with PTSD, indicating its potential role as a biomarker for resilience. Opioids: During traumatic events, beta-endorphin levels initially rise, numbing emotional sensations. However, as trauma subsides, decreased beta-endorphin release results in withdrawal effects, contributing to PTSD symptoms. The kappa-opioid receptors (KORs), influenced by corticotropin-releasing factor (CRF) and dynorphin, are implicated in fear and stress behaviours. Treatment with buprenorphine/naloxone, which affects KORs, has shown a reduction in PTSD symptoms over a 24-month period. [Nikbakhtzadeh et al., 2020] In PTSD, the endogenous opioid system undergoes chronic downregulation, triggering conditioned passive defence responses and self-destructive behaviours as a means to increase opioid release during stress (e.g., self-harm). While mu-opioid receptors mediate analgesic effects, the kappa-opioid system influences consciousness alterations. This dysregulation is linked to dissociative

• 110. symptoms, with increased kappa-opioid receptor activation in areas like the BNST contributing to enhanced claustrum connectivity, potentially leading to dissociation and dysphoria in PTSD with dissociative subtype. [Rabellino et al., 2017] PTSD AND NEUROINFLAMMATION content Posttraumatic stress disorder (PTSD) has increasingly been linked to heightened systemic inflammation, highlighting its bidirectional nature where inflammation may both contribute to PTSD onset and be exacerbated by it. It is postulated to be a significant contributor to severity and treatment resistance. [Sumner et al, 2020] Neuroinflammation in Psychiatry Simplified – The Link Between the Immune System and The Brain- Dr Sanil Rege Exposure to traumatic events disrupts the sympathetic-adrenal-medullary (SAM) and hypothalamic-pituitary-adrenal (HPA) axes, resulting in cortisol dysregulation, including variations in secretion patterns. [Sun et al., 2021] Prolonged stress can induce glucocorticoid receptor resistance (GCR), promoting chronic inflammation and somatic diseases. This inflammatory state, characterised by elevated cytokines like IFN-γ, IL-6, TNF-α, and IL-17, signals a heightened proinflammatory status with increases in Th1 and Th17 immune cells. [Sun et al., 2021] Neuroinflammation plays a significant role in PTSD pathophysiology, with activation of neuroimmune cells such as microglia and astrocytes altering the neurobiological environment through the release of inflammatory markers. [Katrinli et al., 2022] Microglia, the resident immune cells of the central nervous system

• 111. (CNS), play a critical role in synaptic pruning, chemotaxis, and neurogenesis under normal conditions. However, in PTSD, microglial activation becomes maladaptive, releasing both pro- and anti-inflammatory cytokines that disrupt homeostasis. These cytokines include IL-1β, TNF-α, and IL-6, which further promote inflammation in the brain, affecting neural circuits involved in fear, memory, and emotional regulation. [Bonomi et al., 2024] Astrocytes also contribute significantly to neuroinflammation by releasing cytokines and regulating the blood-brain barrier (BBB) integrity. They interact with microglia in a feedback loop, perpetuating the inflammatory response. Astrocytic dysfunction is potentially the main pathological basis for the co-morbidity of PTSD and sleep disturbances. [Li et al., 2022] Astrocytic alterations are noted in PTSD models, such as changes in astrocytic processes, density, and neurotrophic factor production, including brain-derived neurotrophic factor (BDNF). [Li et al., 2023] Reduction in BDNF may impair synaptic plasticity and contribute to the cognitive and emotional deficits seen in PTSD patients. HPA axis dysregulation due to chronic trauma impacts cortisol feedback mechanisms, failing to inhibit proinflammatory cytokines and exacerbating neuroinflammation. [Li et al., 2023] This dysregulation facilitates cytokine signalling from peripheral to central pathways, affecting key brain regions like the amygdala and hippocampus. [Bonomi et al., 2024] Inflammation-induced changes in neurotransmitter synthesis affect serotonin, dopamine, and glutamate systems. For example, cytokines upregulate the kynurenine pathway, depleting serotonin precursors and increasing neurotoxic quinolinic acid. [Katrinli et al.,

• 112. 2022] Additionally, cytokines affect dopamine synthesis by depleting tetrahydrobiopterin (BH4), a critical enzyme cofactor. [Katrinli et al., 2022] PTSD frequently coexists with immune-related conditions such as asthma, autoimmune diseases, and cardiovascular disorders, possibly due to shared inflammatory pathways. Increased levels of cytokines like IL-6, IL-17, and TNF-α link systemic inflammation to PTSD’s clinical manifestations. [Katrinli et al., 2022] Clinical Implications: Elevated pro-inflammatory cytokines, such as IL-6 and TNF-α, have been observed in individuals with PTSD, correlating with worse clinical outcomes. [Sumner et al, 2020] Elevated levels of inflammatory biomarkers, such as white blood cell (WBC) counts, C-reactive protein (CRP), fibrinogen, and erythrocyte sedimentation rate (ESR), have been linked to worse clinical outcomes in PTSD. [Eswarappa et al, 2019] In particular, low cortisol levels, which also predict poor PTSD outcomes, further support the notion of dysregulated stress and immune responses in this condition. Given the association between inflammation and poorer PTSD outcomes, addressing inflammation through targeted interventions could offer a novel therapeutic approach. [Eswarappa et al, 2019] Considering inflammation’s role in PTSD, anti-inflammatory treatments, including monoclonal antibodies and COX-2 inhibitors, have demonstrated the potential to

• 113. reduce PTSD-like symptoms in preclinical models. [Katrinli et al., 2022] Additionally, adjunctive treatments with glucocorticoids, beta-blockers, and angiotensin receptor blockers are under investigation to mitigate inflammation and enhance outcomes. (See Anti-Inflammatory Treatments Later) ALLOSTATIC LOAD MODEL OF PTSD content The allostatic load model describes how cumulative stress responses contribute to the development and persistence of PTSD. [Carbone et al., 2022] It highlights the concepts of allostasis, sensitization, and kindling as key mechanisms that lead to physiological dysregulation after repeated trauma exposure. [Burback et al., 2024] Sensitization involves an increased response to triggers over time, resulting in progressively heightened physiological reactions across biological systems in PTSD. Kindling refers to the underlying limbic abnormalities that emerge with repeated stress, increasing vulnerability to subsequent PTSD episodes. Together with fear conditioning and extinction failure, these processes are fundamental to PTSD's onset and persistence. Repeated stress cycles disrupt neuroendocrine, neuroimmune, and cardiovascular systems, increasing allostatic load. Allostatic load reflects the "wear and tear" from chronic stress adaptation, marked by HPA axis dysregulation, immune changes, and structural and functional brain alterations (e.g., in the hippocampus, amygdala, and prefrontal cortex). [Carbone et al., 2022] When stress exceeds coping capacity, allostatic overload occurs, leading to sustained symptom severity and broader system failure. Biomarkers of allostatic load, such as cortisol, cytokines, and cardiovascular indicators, help quantify stress impact and guide targeted interventions. [Carbone et al., 2022]

• 114. PTSD AND PAIN content Posttraumatic stress disorder (PTSD) and chronic pain are intertwined through shared neural circuits and overlapping pathophysiological mechanisms. The ACC projects to the thalamus, amygdala, hypothalamus, and PAG, regulating autonomic responses and contributing to dysautonomias seen in chronic pain syndromes. [Fenton et al., 2015] Trauma-induced changes, such as increased amygdala sensitivity, HPA axis dysregulation, and altered dopaminergic signalling, heighten inflammation and amplify pain responses. This links adverse childhood experiences (ACEs) to both fibromyalgia and PTSD. [Gasperi et al., 2021] Individuals with co-occurring chronic pain and PTSD face more severe symptoms, including heightened pain intensity, emotional distress, and functional impairment, compared to those with either condition alone. [Scioli-Salter et al., 2015] The comorbidity rates are high, with 50-75% of PTSD patients reporting chronic pain, while 20-37% of chronic pain patients also meet PTSD criteria. [Scioli-Salter et al., 2015] This comorbidity complicates treatment, as pain can act as a trigger for traumarelated memories, while trauma can exacerbate pain perception, creating a cycle of symptom amplification. Women who exhibit higher susceptibility to both conditions may experience symptom fluctuations related to hormonal variations, underscoring the need for tailored interventions. [Scioli-Salter et al., 2015] Neurobiologically, pain and PTSD share common pathways, such as the thalamus-amygdala circuit, which processes pain as an unconditioned stimulus during traumatic events, activating survival-oriented defence

• 115. responses. [Scioli-Salter et al., 2015] The parabrachial nucleus routes pain signals directly to the amygdala, reinforcing fear responses. Long-term potentiation (LTP) within the amygdala further establishes conditioned responses to trauma cues, including pain. [Scioli-Salter et al., 2015] Key neurotransmitters in both PTSD and chronic pain include Neuropeptide Y (NPY), allopregnanolone (ALLO), and the endogenous opioid and endocannabinoid systems. NPY, known for its antistress and antinociceptive effects, is reduced in both conditions, correlating with heightened symptoms. ALLO, which facilitates GABAergic transmission, has anxiolytic and analgesic properties but is often deficient in PTSD and chronic pain. Dysregulated opioid pathways in PTSD contribute to reduced pain thresholds, while the modulation of endocannabinoid signalling shows promise in enhancing fear extinction, potentially benefiting patients with comorbid pain and PTSD. [Scioli-Salter et al., 2015] Shared serotonergic, noradrenergic, and dopaminergic dysfunctions not only contribute to maladaptive responses in PTSD but also play a pivotal role in the development of comorbid pain syndromes. Noradrenergic Dysfunction in Pain and PTSD: Noradrenergic dysregulation, particularly involving the locus coeruleus, amplifies descending pain pathways and perpetuates hyperarousal, increasing pain perception. Impaired noradrenergic inhibition disrupts the modulation of pain signals, leading to hyperarousal and increased pain perception. [Vieira et al., 2021] Additionally, noradrenergic inputs contribute to altered thalamocortical rhythms, which can drive autonomic dysregulation, facilitating the transition from acute to chronic pain. [Fenton et al., 2015] This overlap between noradrenergic dysfunction in PTSD and its role in pain modulation helps explain why individuals with PTSD often experience increased pain sensitivity and persistent pain syndromes. Serotonergic Dysfunction in Pain and PTSD: 5-HT is a key neurotransmitter that modulates synaptic transmission and plasticity across the central nervous system (CNS), influencing diverse processes, including mood regulation, pain perception, and emotional responses. In regions like the ACC, insula, and amygdala, serotonin exerts both excitatory and inhibitory effects, depending on the receptor subtype and neural circuits involved. [Hao et al., 2023]. This modulation extends to the descending pain pathways, where 5-HT can enhance or inhibit pain perception. Altered serotonergic projections from the amygdala to the prefrontal cortex mediate anxiety-induced hyperalgesia, linking the emotional dysregulation characteristic of PTSD to pain hypersensitivity. [Fenton et al., 2015] Dopaminergic Dysfunction in Pain and PTSD:

• 116. Dopaminergic dysfunction in PTSD plays a critical role in both reward processing and pain modulation. Low extracellular dopamine levels correlate with increased pain sensitivity, as reduced dopamine impairs the brain's reward circuits, which are essential for regulating both pleasure and pain perception. [Fenton et al., 2015] In the ventral striatum, this diminished dopamine signalling is associated with anhedonia and emotional numbing, core features of PTSD that further contribute to heightened pain perception. Additionally, increased striatal dopamine transporter (DAT) density has been observed in PTSD, indicating aberrant dopaminergic activity. This increase in DAT density is linked to hyperdopaminergia, which may disrupt standard reward processing, thereby exacerbating pain symptoms. Striatal D2 receptor activation plays a compensatory role by enhancing descending pain inhibition through serotonergic and dopaminergic pathways in the spinal cord. [Fenton et al., 2015] D2 receptor activation has been shown to reduce persistent pain by inhibiting rostral ventromedial medulla (RVM) nociceptors, which are central to pain modulation. However, patients with low endogenous dopamine levels rate pain stimuli as more intense, reflecting the link between impaired dopaminergic signalling and increased pain perception. [Fenton et al., 2015] In PTSD, this dopaminergic dysfunction reduces top-down control from the prefrontal cortex over subcortical pain circuits, leading to persistent pain and maladaptive stress responses. D2-like receptor agonists, when combined with μ-opioid receptor agonists, may offer improved analgesic effects, highlighting the potential therapeutic role of dopamine modulation in managing comorbid pain and PTSD. [Wang et al., 2021] Dysfunction in the top-down regulation by the vmPFC, combined with enhanced afferent signalling, drives stress-induced sensitisation, facilitating the progression from acute to chronic pain. [Fenton et al., 2015] Importantly, patients with PTSD often exhibit paradoxical pain responses, including both hyposensitivity associated with dissociation and hyperresponsiveness linked to anxiety, reflecting broader dysregulation within corticolimbic networks. [Defrin et al., 2015] This highlights the necessity for integrated treatments targeting the shared neurobiological substrates of PTSD and chronic pain, as treating one condition in isolation may yield suboptimal outcomes. Therapeutic approaches targeting NPY, ALLO, and the endocannabinoid system offer potential pathways for managing this comorbidity, emphasising personalized treatments based on neurobiological profiles and sex differences. [Scioli-Salter et al., 2015] Integrative strategies, such as cognitive-behavioural therapies, may enhance pharmacological

• 117. interventions by improving amygdala regulation, as suggested by functional neuroimaging studies of prefrontal cortex modulation. NEUROBIOLOGICAL CORRELATES OF PTSD SYMPTOMS content 1.Intrusion Symptoms [Ressler et al., 2022] Amygdala Hyperactivity: Drives intrusive memories, flashbacks, and heightened emotional reactivity to trauma-related cues, even in safe environments. Hippocampal Dysfunction: Disrupts contextual memory processing, contributing to the misinterpretation of neutral stimuli as threats. Prefrontal Cortex (PFC) Dysregulation: Decreased inhibition of intrusive memories, exacerbating the re-experiencing of traumatic events. DMN alteration may contribute to rumination and alterations in self-awareness. [Daniels et al., 2011] In PTSD, especially from early-life trauma, DMN disruptions—marked by reduced connectivity and myelination (e.g., lower corpus callosum integrity)-impair self-

• 118. referential processing, emotion recognition, and autobiographical memory. This contributes to symptoms like alexithymia, dissociation, and altered self-perception. [Daniels et al., 2011] 2. Sleep Disturbances 70-90% of individuals with PTSD report sleep disturbances, with insomnia and nightmares being key symptoms. [Lancel et al., 2021] Pre-existing sleep problems increase the vulnerability to PTSD, while persistent sleep disturbances often continue even after other symptoms improve. Disrupted Sleep Architecture: PTSD is associated with increased time in light sleep, reduced slow-wave sleep, and fragmented REM sleep, impairing restorative sleep functions. [Shalev et al., 2024] A meta-analysis of polysomnographic studies has shown a pattern of more N1 and less N3 sleep as well as greater REM density in PTSD populations, making sleep in PTSD, in general, more superficial and less regenerative. In addition, there are indications that several aspects of sleep, such as sleepdisordered breathing, worsen with a longer duration of the disorder and, together with obesity, contribute to premature cognitive ageing. [Nijdam et al., 2023] REM Sleep and Nightmares: Frequent nightmares often occur during REM sleep, as this phase is involved in fear memory consolidation, contributing to trauma reactivation. [Pace-Schott et al., 2015] 3. Hypervigilance Acute-Threat Response: Hypervigilance in PTSD is driven by the brain’s acute-threat response system, which maintains heightened alertness and reactivity to potential dangers. Amygdala and dACC Overactivity: Increased activity in the amygdala, dorsal anterior cingulate cortex (dACC), and insula heightens threat detection, leading to a constant sense of danger. Amplified Startle Response: PTSD patients exhibit an exaggerated startle reflex, indicating persistent hyperarousal and vigilance even in non-threatening settings.

• 119. Physiological Correlates: Elevated heart rate, increased skin conductance, and dysregulated HPA axis responses are common, contributing to sustained arousal. 4. Persistence of PTSD Symptoms [Shalev et al., 2024] Kindling Hypothesis: Repeated trauma exposure reinforces maladaptive neural activation patterns, making symptoms more resistant to extinction. Allostatic Load: Chronic stress causes “wear and tear” on emotion regulation systems, especially in the hippocampus, compromising safety signal integration. Impaired Extinction Learning: Deficits in the prefrontal cortex and hippocampal function hinder the extinction of fear memories, promoting chronic symptom persistence. Persistent Hyperexcitability: Persistent hyperactivity in fear circuits reinforces the recurrent nature of intrusive symptoms in PTSD. [Rosen & Schulkin, 2022] Endocrine Dysregulation: Persistent HPA axis dysfunction, marked by increased CRF signalling, amplifies noradrenergic activation and disrupts top-down control from the prefrontal cortex, sustaining hyperarousal and impeding fear extinction in PTSD.

• 120. PTSD PHENOTYPES content The dynamic interaction between the mPFC and the amygdala creates two distinct phenotypes in PTSD patients. [Yehuda et al., 2015], [Lanius et al., 2010], [Lanius et al., 2018] 13–30% of individuals with PTSD meet the criteria for the dissociative subtype. [Fenster et al, 2018]. Emotional Undermodulation (PTSD + Hyperarousal):

• 121. Diminished vmPFC inhibition of the amygdala and BNST leading to increased threat expression and reduced fear extinction. Bottom-up processing from the PAG to the bilateral CMA and from the BLA to the vmPFC suggests defensive responding and chronic fear responses driven by midbrain and limbic regions. Chronic PTSD is associated with elevated BNST activity, which impairs the HPA Axis, leading to enhanced processing of negatively valenced information. Hyperarousal is mediated by noradrenergic projections to the BNST and negative valence by serotonergic inputs abundant in the BNST. Emotional Overmodulation (PTSD + Dissociative Subtype): The VMPFC shows increased inhibition of the amygdaloid complexes. Predominant top-down connectivity between the bilateral CMA and PAG and vmPFC with the BLA is associated with symptoms of depersonalisation, derealisation and dissociative features. INTEGRATED NETWORK MODEL OF PTSD content Three key brain networks have been identified as central to higher cognitive functions: Salience Network (SN):

• 122. Anchored in the anterior cingulate cortex and ventral anterior insula and involves the amygdala and thalamus. Detection of salient internal and external stimuli to direct behaviour Dysfunction in this network can give rise to alterations in arousal The SN processes “bottom-up” aversive or other salient attention-demanding stimuli or experiences. Default Mode Network (DMN): Anchored in the medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC), and angular gyrus. Involved in emotional regulation, social cognition, future-oriented thinking, autobiographical memory, self-awareness, and perspective-taking Dysfunction in this network can alter the cognitive processing of external information and relating it to the self. (self-referential processing) Central Executive Network (CEN) or Executive Control Network (ECN): Anchored in the dorsolateral prefrontal cortex (dlPFC) and posterior parietal cortex. Seat of executive functioning, cognitive control and working memory Dysfunction in this network leads to cognitive dysfunction Integrated (Triple) Network Model of PTSD: [Hinojosa et al., 2024] Disruptions in these networks in PTSD manifest through abnormal connectivity and activation patterns, contributing to symptoms like hyperarousal, re-experiencing, and deficits in emotional regulation. [Yehuda et al., 2015] Increased activation of the amygdala and dACC within the SN is linked to hyperarousal and hyperreactivity in PTSD. Reduced activation in the hippocampus and vmPFC, part of the DMN, correlates with intrusive memories, impaired fear extinction, and emotional regulation deficits. Decreased activation in CEN regions is associated with impaired cognitive control and executive function in PTSD patients. Connectivity patterns vary, with decreased DMN connectivity at rest, increased SN activation during threat processing, and reduced CEN connectivity.

• 123. Impaired connectivity between the SN and DMN limits transitions between selfreferential states and cognitive control, while increased CEN influence on the DMN indicates abnormal modulation. PTSD patients show a shift to a "small-world" network topology, marked by greater network segregation and reduced integration, particularly within the DMN. Greater network segregation, especially in the DMN, and decreased hippocampusPFC connectivity are associated with more severe re-experiencing symptoms. Both within-network coherence and between-network dynamics contribute to the persistence of PTSD symptoms and treatment resistance. STAGING MODEL OF PTSD content Recently, a staging model of PTSD has been proposed, emphasising a four-stage trajectory ranging from trauma exposure without symptoms (Stage 0) to severe, unremitting chronicity (Stage 4). [Nijdam et al., 2023] The aims of the Stage-Specific model of PTSD are to: 1. Organise PTSD progression using neurobiological markers, stress reactivity, information processing, and consciousness dimensions to guide interventions. 2. Integrate neurobiological and phenomenological factors to enhance understanding of PTSD’s development, allowing for personalised, phase-specific care.

• 124. 3. Address treatment resistance by matching interventions to the neurobiological state at each stage, improving precision. 4. Enable early intervention by identifying initial risk stages and focusing on preventing chronic PTSD. 5. Tailor treatment based on symptom severity, functional impact, and evolving clinical data, supporting individualised care trajectories. 6. Incorporate transdiagnostic perspectives to address a range of posttraumatic conditions, enhancing comprehensive management. 7. Refine intervention timing and methods for better outcomes in PTSD treatment. TREATMENT OF PTSD - GENERAL PRINCIPLES content PTSD's pathogenesis, as illustrated in the diagram, centres on two critical processes: Kindling: This process involves increasingly low-severity stimuli, triggering negative responses over time. Sensitization: Repeated exposure to negative stimuli leads to progressively stronger responses. Effective treatment aims to achieve fear extinction and desensitization while intervening in the kindling process.

• 125. Traditionally, PTSD treatments have targeted abnormal fear circuits and trauma-related cognitions, utilising exposure-based psychotherapies and medications focused on anxiety and hyperarousal. While global treatment guidelines may differ slightly, Cognitive Behavioral Therapy (CBT) and selective serotonin reuptake inhibitors (SSRIs) are commonly recommended as first-line interventions. [Burback et al., 2024] Prazosin is often considered for managing nightmares, though guidelines vary in its recommendation. Recent evaluations call for updated guidelines that now incorporate complex PTSD (CPTSD) considerations, as seen in the Australian guidelines. [Burback et al., 2024] Trauma-Focused Psychotherapies (TFPs) have demonstrated superior effectiveness; however, guideline variations reflect differing perspectives on pharmacotherapy’s role, considering its limitations and patient preferences. [Burback et al., 2024] SUMMARY OF GUIDELINES FOR PTSD content A systematic review of clinical guidelines for PTSD treatment reveals several consensus recommendations, with some variability in details. Key recommendations include: [Martin et al., 2021] Pharmacological Treatment: SSRIs are universally endorsed as first-line treatment for PTSD, particularly paroxetine and fluoxetine, along with the SNRI venlafaxine. These medications have shown statistically significant but modest improvements in PTSD symptoms compared to placebo, similar to their effects in depression.

• 126. TCAs are suggested as an alternative first-line option by the WHO, mainly when SSRIs or venlafaxine are unavailable, ineffective or if severe comorbid depression is present. However, TCAs generally have less supporting evidence and greater concerns regarding side effects. Some research suggests comparable efficacy to SSRIs in combat-related PTSD, indicating the need for further investigation. Psychotherapy vs. Pharmacotherapy: Approximately one-third of guidelines prioritise trauma-focused psychotherapies (e.g., TF-CBT, EMDR) over pharmacotherapy as first-line treatments, supported by meta-analyses showing larger effect sizes for psychotherapies compared to medications. However, the choice between therapy and medication should be based on patient preference, availability, and comorbid conditions like depression. CBT, particularly trauma-focused modalities like Cognitive Processing Therapy (CPT), Prolonged Exposure (PE), and Image Rehearsal Therapy (IRT), is the preferred first-line psychological treatment. EMDR is often recommended separately, although both EMDR and CBT demonstrate comparable efficacy. The use of the broader term "trauma-focused psychotherapies" may reduce confusion and allow treatment flexibility. Nightmares in PTSD: While nightmares are often resistant to treatment and associated with higher suicide risk, most guidelines lack detailed recommendations. Prazosin is considered a first-line treatment for nightmares by two guidelines, but others either recommend it as a third-line or do not mention it specifically. Meta-analyses show significant effectiveness of prazosin, but recent trials with larger samples report mixed results, suggesting it may be effective for specific subgroups with severe adrenergic dysfunction. IRT is another recommended treatment for nightmares, with evidence suggesting it is as effective as prazosin, especially when combined with CBT for insomnia. IRT

• 127. has a more extensive evidence base yet appears less frequently in guidelines compared to prazosin. In summary, guidelines generally favour SSRIs, trauma-focused psychotherapies, and prazosin or IRT for targeted symptom management, though treatment should be individualised based on patient characteristics and preferences. Further research is needed to clarify subgroup responses, particularly for nightmares and combat-related PTSD. PSYCHOTHERAPY IN PTSD content Psychotherapy can be divided into trauma-focused and non-trauma-focused psychotherapy. Trauma-focused CBT has been extensively studied and shown to be effective. Prolonged exposure (PE) therapy and cognitive processing therapy (CPT) are two types of trauma-focused CBT. Repeatedly writing and talking about the details of the traumatic memory are central therapeutic elements of both Cognitive Processing Therapy (CPT) and Prolonged Exposure (PE). They are based on the principles of extinction learning, habituation and desensitisation. Trauma-focused therapy Prolonged exposure therapy (PET): [Schnyder et al., 2015] Two key components: 1. Imaginal Exposure: Revisiting trauma memories with the processing of emotions. 2. In Vivo Exposure: Gradual exposure to avoided, safe situations. Successful treatment requires two conditions: activation of trauma memory and disconfirmation of expected harm, both validated as mechanisms for reducing PTSD symptoms. Based on Emotional Processing Theory, PE activates trauma memory and disconfirms expected harm, reducing PTSD symptoms. Reductions in negative cognitions are central to symptom improvement Cognitive-processing therapy (CPT): [Resick & Schnicke, 1992] Uses education and cognitive restructuring without detailed trauma recounting. CPT without trauma accounts (CPT-C) shows faster improvement through Socratic dialogue. The focus is on beliefs about the trauma rather than reexperiencing it.

• 128. It also addresses shame, guilt or feelings of mistrust. Present-Centered Therapy (PCT) effectively addresses PTSD by focusing on current symptoms, not trauma memory. Both CPT and PCT demonstrate that PTSD can be treated without detailed trauma exposure. In this sense, culturally adapted CBT has also been useful as this technique offers a more specific paradigm to treat PTSD. Narrative exposure therapy (NET): This therapy was developed for the survivors of the Pinochet regime in Chile and has proven to be very useful in overcoming trauma. Addresses cumulative trauma by helping individuals construct a chronological life story that includes both traumatic and positive events. Focuses on recalling the most distressing experiences while maintaining a connection to the “here and now,” linking emotional responses to their autobiographic context. Encourages reliving sensory, emotional, and physiological trauma memories to foster exposure and reduce avoidance. Integrates positive memories to mobilize personal resources, promoting healing and therapy continuation. Proven effective in reducing PTSD symptoms, improving psychosocial functioning, and enhancing physical health. Emphasises processing of trauma and associated guilt or shame, particularly for excombatants, to aid reintegration. It is recommended for adults with PTSD where trauma is linked to genocide, civil conflict, torture, political detention, or displacement. Eye Movement Desensitization and Reprocessing (EMDR) [Shapiro, 2014] Eight-phase approach focused on processing unintegrated trauma memories linked to current dysfunction. Clients briefly focus on trauma images, negative beliefs, and bodily sensations, with short exposures paired with bilateral eye movements. EMDR reduces arousal, negative affect, and memory vividness, creating connections to adaptive memory networks.

• 129. Key elements include stabilization, memory processing, and skills training for social interactions. Effective across past memories, present triggers, and future challenges, promoting adaptive functioning in daily life. content Non-trauma-focused therapy Supportive therapy Non-directive counselling Mindfulness and patient-centred therapy Interpersonal therapy Yoga and mindfulness training PHARMACOTHERAPY IN PTSD content When reviewing methodologically robust pharmacotherapy trials, Hoskins and colleagues found that amongst antidepressants, only fluoxetine, sertraline, paroxetine, and venlafaxine have statistically significant data on reducing PTSD symptoms compared to placebo. [Hoskins et al, 2021] Quetiapine has evidence when used as monotherapy. Prazosin and risperidone show benefits as augmentation agents. [Hoskins et al, 2021] SSRIs (Selective Serotonin Reuptake Inhibitors) SSRIs remain the first-line treatment for PTSD, with sertraline and paroxetine approved by the FDA. These medications are effective in reducing re-experiencing, avoidance, and numbing symptoms but are less effective for hyperarousal. [Shalev et al., 2024] Paroxetine has shown better efficacy than sertraline in clinical trials, particularly for civilian females, but carries side effects like sedation, weight gain, and sexual dysfunction. Withdrawal can also be problematic, making it less desirable for women of childbearing age due to its pregnancy risk. [Bajor et al., 2022] Sertraline, while also effective, has demonstrated mixed results, especially in male veterans. It is generally better tolerated than paroxetine, with fewer side effects related to sedation and weight gain. While escitalopram and citalopram have shown mixed results, they may be considered alternatives due to their milder safety profiles.

• 130. SNRIs (Serotonin-Norepinephrine Reuptake Inhibitors) Venlafaxine is the most studied SNRI for PTSD, demonstrating similar efficacy to SSRIs, particularly for re-experiencing and avoidance. [Davidson et al., 2006] However, it has a limited impact on hyperarousal and can exacerbate insomnia, making it a second-line option. Side effects of venlafaxine include sexual dysfunction and potential cardiovascular concerns, which should be considered when treating PTSD patients with preexisting heart conditions. [Davidson et al., 2006] Tricyclic Antidepressants (TCAs) TCAs, such as imipramine and amitriptyline, can be beneficial in PTSD but are generally reserved for cases where SSRIs or SNRIs are ineffective or not tolerated due to side effects. [Davidson, 2015] These medications are associated with significant anticholinergic effects, cardiac risks, and overdose potential, necessitating careful monitoring, especially in patients with suicidal ideation. [Kosten et al., 1991] Revisiting Tricyclic Antidepressants: Understanding the Differences and Advantages for Effective Depression Treatment MAOIs (Monoamine Oxidase Inhibitors) MAOIs have shown limited evidence in PTSD treatment but may be useful in select cases where other antidepressants have failed. [Ipser & Stein, 2012] Strict dietary restrictions and potential severe side effects, including hypertensive crises, limit their use to highly resistant cases. Monoamine Oxidase Inhibitors (MAOI) – Mechanism of Action | Psychopharmacology | Clinical Application Atypical Antipsychotics Risperidone, quetiapine, and olanzapine are often used as adjuncts to antidepressants in treatment-resistant PTSD, helping with re-experiencing and hyperarousal symptoms. [Krystal et al., 2011] Risperidone: While it has shown some benefit in reducing re-experiencing, a large RCT found no significant difference compared to placebo for core PTSD symptoms,

• 131. though secondary analyses suggested mild improvements in sleep. [Krystal et al., 2016] Quetiapine: It has demonstrated improvement in overall PTSD symptoms, particularly insomnia, but is associated with metabolic side effects, weight gain, and sedation. [Villarreal et al., 2018] Olanzapine: Shows benefits for avoidance and numbing symptoms but has a high risk of weight gain and metabolic syndrome. [Carey et al., 2012] A Simplified Guide to Oral Antipsychotic Medications – Mechanism of Action, Side Effects and Need to Know Points Anti-adrenergic drugs (α1, α2 and β receptors) (e.g. prazosin, guanfacine, alfuzosin, doxazosin, propranolol and clonidine). Alpha-1 Adrenergic Antagonists Prazosin: Prazosin is effective in reducing nightmares and improving sleep quality in PTSD, with studies suggesting that higher pretreatment blood pressure predicts better outcomes. [Raskind et al., 2018] A Systematic review and meta-analysis showed that Prazosin shows good evidence in the treatment of PTSD with a positive effect on PTSD scores, nightmares and sleep quality. [Reist et al., 2021] Treatment of PTSD with prazosin is usually initiated at a dose of 1 mg, with monitoring for hypotension after the first dose. The dose is then gradually increased to maintenance levels of 2-6 mg at night. In treating PTSD-related symptoms, prazosin's mean optimal dose is generally 16 mg nightly for men (with some requiring up to 25–30 mg) and 7 mg nightly for women. Studies of military patients with PTSD have used higher doses (e.g., 10-16 mg at night), with the maximum dose used clinically without side effects at 50 mg /day. [Koola et al., 2014] Due to its short half-life, BD or TDS dosing may be required. Doxazosin Doxazosin, an alternative to prazosin, offers a longer half-life and potentially fewer side effects, making it an option for patients who struggle with prazosin’s hypotensive effects. [Rodgman et al., 2016]

• 132. Once daily dosing. Dose: 8 to 16 mg/day. (Higher doses of up to 48 mg /day have been used. Smith and Koola, Unpublished). Clonidine: Alpha-2 presynaptic agonist: Clonidine has shown promise in reducing PTSD severity, particularly in veterans, as indicated by significant improvements on the Clinical Global Impression (CGI) scale. [Burek et al., 2021] It is used primarily for managing nighttime symptoms, including nightmares and sleep disturbances, by acting centrally to inhibit noradrenaline release, leading to decreased arousal and improved sleep quality [Wendell & Maxwell, 2015] Clonidine's action on the locus coeruleus is thought to contribute to its hypnotic effects, pain signal modulation, and reduction of anxiety and depressive symptoms. Compared to prazosin, clonidine’s effects may be more centrally mediated, affecting noradrenaline release and sensitivity, which could help desensitize the noradrenergic system, potentially reducing hypervigilance, insomnia, flashbacks, and nightmares. Clonidine's impact on REM and non-REM sleep could enhance memory consolidation, which may benefit emotional memory processing and overall PTSD symptomatology. [Miyazaki et al., 2004]; [Lebow & Chen, 2016] Adverse effects during low-dose clonidine use are generally minor, but include potential sedation, hypotension, and dry mouth, which may limit tolerability in some patients. [Detweiler et al., 2016] Studies suggest that clonidine may be comparable to other anti-adrenergic drugs like prazosin, but definitive evidence regarding its superiority or optimal dosing in PTSD treatment is still lacking. [Marchi et al., 2024] Doses below 0.05 mg daily have been reported as ineffective, while doses above 0.25 mg did not yield additional benefits, indicating a potential dose-dependent effect for PTSD-related symptoms, though more research is needed to determine the optimal dosing strategy. [Burek et al., 2021] Despite mixed evidence and a lack of large-scale trials, clonidine may offer an alternative for individuals with PTSD who do not respond to or cannot tolerate other anti-adrenergic agents, particularly for reducing sleep-related symptoms. [Reist et al., 2021] Psychopharmacology and Clinical Application of Guanfacine and Clonidine for ADHD – What’s the Difference? Sleep Medications:

• 133. Trazodone is widely used to manage PTSD-related insomnia, with efficacy attributed to its effects on serotonin, alpha-1 adrenergic, and histamine receptors. It is well tolerated but has potential side effects like sedation and orthostasis. Suvorexant, an orexin antagonist, has shown promise in managing trauma-related insomnia by reducing sleep onset latency and increasing sleep duration. Benzodiazepines are not recommended for PTSD, as they lack efficacy for core symptoms and have a high potential for dependence, particularly in trauma-exposed populations. Benzodiazepines are also associated with a 150% increased risk of PTSD development post-trauma. [Campos et al., 2022] Benzodiazepines can exacerbate avoidance and depressive symptoms, most likely due to their strong sedative, addictive, and dissociative properties. [Du, et al, 2022] A review of 99 RCTs involving 10,481 participants found that prazosin may be the most effective treatment for insomnia, nightmares, and poor sleep quality in PTSD. In contrast, SSRIs, mirtazapine, Z-drugs, and benzodiazepines showed limited efficacy, while risperidone and quetiapine posed high risks of somnolence without clear benefits. Hydroxyzine, trazodone, nabilone, paroxetine, and MDMA-assisted psychotherapy show promise but require further research. [Lappas et al., 2024] Ketamine: Intravenous ketamine has demonstrated rapid reductions in PTSD symptoms, particularly for depressive comorbidity, with benefits lasting up to six weeks after multiple doses. [Feder et al., 2021] Its potential for misuse requires careful monitoring and consideration in treatmentresistant cases. Ketamine and Esketamine in Depression – A Synopsis on Efficacy and Mechanism of Action Memantine: Memantine, a glutamatergic modulator, has shown promising results in reducing PTSD symptoms. Preclinical findings suggest that memantine enhances hippocampal neurogenesis, aiding in the forgetting of traumatic memories and reducing anxiety-like behaviours. [Ishikawa et al., 2019]

• 134. In an open-label trial among civilian female PTSD patients, memantine significantly improved PTSD symptoms and was well tolerated. [Hori et al., 2021] An open-label trial of memantine in veterans improved cognitive symptoms, PTSD symptoms, and mood. [Ramaswamy et al., 2015] Memantine – Mechanism of Action | Psychopharmacology | Clinical Application Lamotrigine: Lamotrigine may be effective in treating PTSD, particularly for intrusive and avoidance/numbing symptoms, with responses observed across genders and trauma types. However, the small sample size limits the assessment of effect size. [Hertzberg et al., 1999] Lamotrigine – Mechanism of Action, Efficacy, Side Effects and Clinical Pearls Topiramate: Topiramate showed a medium but not significant effect on overall PTSD symptoms, with a small, significant reduction in hyperarousal. [Varma et al., 2018] It did not significantly impact reexperiencing or avoidance symptoms, with similar results across veterans and nonveterans, and as both monotherapy and adjunctive therapy. Cannabis and Cannabidiol (CBD) Preliminary evidence suggests cannabis may reduce overall PTSD symptoms, but high-quality data is lacking. Side effects, such as psychoactive responses and potential worsening of symptoms, limit its use in clinical practice.[Bedard-Gilligan et al., 2018] A recent meta-analysis suggested that while cannabinoids may offer some therapeutic potential for reducing PTSD symptoms related to intrusion (cluster B) and arousal/reactivity (cluster E), these benefits are limited and must be viewed within a broader risk context. Cannabinoids have been associated with increased suicidal ideation and aggressive behaviour, particularly among individuals with comorbid cannabis use disorder (CUD).

• 135. In a small study (n=10), 5 mg of THC twice daily as an add-on improved sleep, reduced nightmares, hyperarousal, and overall PTSD symptom severity. [Roitman et al., 2014] Similarly, the THC analogue nabilone showed benefits in sleep and symptom reduction. However, the positive effects of THC appear limited, leaving many PTSD features unchanged. [Jetly et al., 2015] Medicinal Cannabis – Psychopharmacology and Clinical Application Reconsolidation Therapy (RT) Propranolol-induced reconsolidation impairment effectively reduces recall of aversive memories and emotional responses, showing benefits in alleviating psychiatric symptoms and cue reactivity in conditions like PTSD, addiction, and phobia, compared to placebo. [Pigeon et al., 2022] An updated meta-analysis found no significant effect compared to placebo in disrupting traumatic memory consolidation. [Steenen et al., 2022] Novel and Emerging Treatments Anti-Inflammatory Agents: [Lee et al, 2022]. ACE Inhibitors and ARBs (e.g Captopril, Candesartan, Telmisartan): Prevent synthesis of ACE inhibitors or block ARB angiotensin II receptors, reducing inflammation. Cannabis e.g Nabilone: Enhances endocannabinoid signalling with anti-inflammatory effects. Glucocorticoids (e.g. Hydrocortisone, Prednisolone, Dexamethasone): Inhibits cytokine expression via genomic mechanisms. Monoclonal Antibodies Against Cytokines (e.g. Infliximab (anti-TNF-α), Adalimumab (anti-TNF-α), Tocilizumab (anti-IL-6 receptor). Prevent cytokines from binding to their receptors, reducing inflammation.

• 136. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) (e.g Celecoxib, Ibuprofen, Naproxen): Inhibit COX-2, reducing pro-inflammatory cytokine production. Neurofeedback: [Askovic et al., 2023] Neurofeedback is postulated to reduce nervous system arousal and enhance connectivity within the Default Mode and Salience Networks when introduced early in PTSD treatment. It improves brainwave synchrony, normalises network connectivity, and restores the brain's excitatory/inhibitory balance, leading to better emotional self-regulation and reduced PTSD symptoms, potentially resulting in lasting symptom relief. Evidence suggests that neurofeedback (NFB) has moderate benefits for reducing PTSD symptoms, along with positive effects on depression and anxiety. These effects were consistent across diverse trauma types and populations. Modulating alpha rhythm appears to be a promising NFB protocol, with observed changes in DMN and SN connectivity correlating with decreased PTSD severity. ADHD Treatment via QEEG-Informed Neurofeedback Treatment Stratification and Predictors of Response: Awaiting Multi-Centre Replication Vagal Nerve Stimulation (VNS) VNS aims to modulate the parasympathetic system to counteract the sympathetic response and facilitate rapid memory storage. It enhances memory and neural plasticity, particularly in fear extinction pathways such as the infralimbic prefrontal cortex and basolateral amygdala. In PTSD models, VNS paired with exposure therapy has reversed impaired extinction and prevented fear relapse, indicating robust, lasting effects. [McIntyre, 2018] Stellate Ganglion Block: The stellate ganglion is part of the sympathetic nervous system and is a cluster of nerve cell bodies between the C6 and C7 vertebrae.

• 137. Since the stellate ganglion is connected to the amygdala, it has been explored as a potential alternative treatment option for PTSD. Stellate ganglion block (SGB) can regulate the autonomic nervous and cerebrovascular systems, dilate blood vessels, and improve circulation; therefore, it is widely used in treating head, neck, and upper limb pain. A stellate ganglion block (SGB) is a procedure involving the injection of a local anaesthetic surrounding the stellate ganglion to inhibit sympathetic outflow to the ipsilateral portion of the head, neck, thorax, and upper extremities. [Blakey et al., 2024] SGB's benefit in PTSD is that SGB decreases nerve growth factor levels, thus reducing noradrenaline and the hyperaroused state of the sympathetic nervous system present in PTSD. One RCT found benefits, while another showed no significant difference. It is considered an experimental treatment currently. [Bajor et al., 2022] It may also specifically be helpful in patients with PTSD and comorbid head, neck, and upper limb pain. [ Lipov et al, 2009] In a randomised controlled trial, SGB showed the most significant reductions in arousal and reactivity symptoms (e.g., hypervigilance, concentration, and sleep disturbances) and clinician-rated reexperiencing symptoms (e.g., physiological and emotional reactions to trauma). [Blakey et al., 2024] Neuromodulation: There is no evidence that rTMS or ECT reduce PTSD symptoms; however, they may be effective in patients with refractory depression and comorbid PTSD. Dual-tDCS, high-frequency rTMS, intermittent theta burst stimulation, and lowfrequency rTMS significantly reduced PTSD symptoms at the treatment endpoint, but effects were not sustained at follow-up. [Liu et al., 2024] No significant difference was observed between active treatments and sham controls. Additionally, synchronized TMS reduced depression symptoms at the endpoint, and dual-tDCS reduced anxiety symptoms at follow-up. Overall, these neuromodulation methods were effective initially but showed limited long-term efficacy. There are case reports of Deep Brain Stimulation (DBS) showing efficacy in PTSD, and trials are underway. [Du et al., 2022]

• 138. MDMA (3,4-Methylenedioxymethamphetamine): MDMA-assisted psychotherapy is currently considered an experimental treatment for PTSD and should be approached with caution. While some clinical trials have demonstrated potential benefits in treatment-resistant PTSD cases, significant concerns about safety, adverse events, and abuse potential persist. [Yang et al., 2024]. FDA reviews have raised concerns about MDMA’s safety, potential for abuse, and design biases in registration trials, limiting its approval for clinical use. The recent FDA rejection for broader clinical use highlights the need for strict regulation and limited application. Psychedelics and Hallucinogens in Psychiatry – Mechanisms of Action and Clinical Application Other experimental treatments - D-cycloserine (glycine receptor agonist), endocannabinoids, neuropeptides (NPY antagonists, cholecystokinin antagonists, substance P antagonist, and nalmefene (endogenous opioid antagonist)), ketamine, mifepristone and hydrocortisone. Prevention of PTSD: Propranolol: In PTSD, reactivated memories become temporarily labile and require stabilisation, which is known as reconsolidation. As PTSD is associated with a hyper-noradrenergic state and β-noradrenergic receptor stimulation has been found to facilitate emotional memory reconsolidation, using a β-noradrenergic receptor antagonist may prevent traumatic memory reconsolidation and thus may help in addressing intrusion symptoms of PTSD. [Roullet et al, 2021] Propranolol administered prior to trauma memory reactivation decreased the severity of PTSD symptoms, reduced physiological responses (e.g., heart rate, skin conductance, blood pressure), and improved cognitive performance in individuals with PTSD. [Young & Butcher, 2020] When used as a preventative measure following trauma, propranolol did not significantly reduce the risk for subsequent PTSD. Hydrocortisone: 30 mg oral hydrocortisone or placebo prior to prolonged exposure (PE) was associated with a greater reduction in total PTSD symptoms in a small study.

• 139. [Yehuda et al., 2015] According to a systematic review and meta-analysis [Astill Wright et al., 2019] ALGORITHM FOR PHARMACOLOGICAL MANAGEMENT OF PTSD content This pharmacological algorithm has been modified from the original framework from [Bajor et al.,2022].

• 140. The modifications incorporate recent scientific insights and practical considerations. Key updates include the addition of specific neurobiological markers such as inflammatory

• 141. markers (e.g., C-reactive protein), neuroendocrine changes (e.g., cortisol levels), and biomarkers of autonomic dysregulation (e.g., heart rate variability) to guide stage-specific interventions. (See earlier section on PTSD and Inflammation) Additionally, clonidine has been repositioned as a primary early option for managing sleep disturbances, reflecting its broader applicability beyond just prazosin failure or sleep onset issues. Another key modification is the consideration of novel treatments like ketamine and MDMA in treatment-resistant cases. These changes are based on emerging evidence supporting a more personalised and neurobiologically-informed approach, emphasising augmentation strategies with anti-inflammatory agents and refined symptom management techniques. The revised algorithm focuses on comprehensive reassessment and a tailored approach to improve PTSD treatment outcomes, aligning with evolving research and clinical practices. Stage 1: Initial Evaluation Confirm Diagnosis of PTSD Conduct comprehensive assessment using DSM-5 criteria. Assess for comorbidities (e.g., substance use, bipolar disorder, depression, dissociation, pregnancy). Integrate neurobiological markers (e.g., inflammation, neuro-hormonal changes) to identify stages and guide treatment decisions. Stage 2: Early Symptom Management Evaluate Sleep Disturbance & Nightmares If sleep disturbances or nightmares are present: First-line: Prazosin or clonidine. Clonidine is added for cases where prazosin shows limited efficacy or is poorly tolerated. Clonidine has benefits for sleep onset difficulties, with prazosin showing benefits only for sleep maintenance. Both options address REM sleep disruptions and hyperarousal. If non-response: Add hydroxyzine or trazodone. Trazodone dose : 12.5 mg to 200 mg. The usual starting dose is 50 mg.

• 142. Hydroxyzine: 25 -100 mg. Monitor Sleep Response If sleep improves, proceed to assess overall PTSD symptoms. If there is no improvement or ongoing sleep issues, consider increasing the dose or switching to alternative agents (e.g., clonidine). Stage 3: Addressing Residual PTSD Symptoms Assess Residual PTSD Symptoms If residual significant PTSD symptoms are present after addressing sleep: Early interventions include psychoeducation, cognitive restructuring, and resilience-building. Initiate SSRIs (e.g., sertraline or paroxetine) or SNRIs (e.g., venlafaxine). Consider anti-inflammatory agents if biomarkers indicate high inflammation. (See Earlier in the section on Anti-Inflammatory Medications) SSRI/SNRI Trial Duration Ensure adequate trial duration (8-12 weeks) with dose optimization. Monitor response: If no response, move to the next line of treatment. If partial response without psychosis, continue for a longer duration or consider augmentation. If Partial response with psychosis, augment with antipsychotics (e.g., olanzapine, aripiprazole). Stage 4: Second-Line Strategies for Persistent Symptoms Second SSRI or SNRI Trial If the initial SSRI or SNRI fails, consider switching to an alternative SSRI or SNRI (e.g., venlafaxine). Evaluate response: If no improvement, consider third-line treatments. If partial response, maintain the current regimen and explore additional augmentation options.

• 143. Third-Line Medications Include options like daytime prazosin or clonidine for persistent hyperarousal. Memantine’s action on the glutamatergic system could help address persistent symptoms, including cognitive impairments, emotional dysregulation, and unresponsive core PTSD symptoms. It can be especially useful for patients with symptoms related to memory dysfunction or anxiety-like behaviour. [Hori et al., 2021]; [Ishikawa et al., 2019]; [Chopra et al., 2011] Consider neurofeedback or rTMS to address persistent emotional dysregulation and attention biases. Stage 5: Treatment-Resistant Cases For cases not responding to three medication trials: Introduce ketamine for rapid symptom relief. Consider advanced interventions like stellate ganglion block, reconsolidation therapy, or high-intensity psychotherapy. Memantine’s potential for broader symptom improvement, including cognitive symptoms and mood stabilisation, aligns with the need for more intensive interventions in treatment-resistant PTSD cases. [Ramaswamy et al., 2015] Monitor Neurobiological Markers and Symptom Progression Reassess regularly to identify changes in neurobiological markers, symptom progression, and emerging comorbidities. Adapt treatment based on current stage and neurobiological profile. Stage 6: Augmentation and Personalised Strategies Augmentation Pathways for Persistent Symptoms Based on predominant symptoms: For high inflammation: Consider anti-inflammatory agents. For emotional dysregulation or cognitive issues: Use rTMS or neurofeedback. For psychotic symptoms, Consider olanzapine or aripiprazole augmentation. Psychosocial Interventions and Long-Term Support Integrate supportive psychotherapy, group therapy, and social interventions.

• 144. Reinforce psychoeducation to enhance resilience and coping. Given its investigational status, MDMA should be considered only for patients with severe, refractory PTSD who have not responded to established interventions and only within controlled clinical trials or compassionate-use frameworks. Alternative interventions, such as ketamine, stellate ganglion block, reconsolidation therapy, and memantine, offer viable options currently. AUSTRALIAN PHARMACOLOGCIAL ALGORITHM FOR THE MANAGEMENT OF PTSD content SSRIs are considered first-line pharmacological treatments. Fluoxetine, Sertraline and Paroxetine have the best evidence for efficacy. Amongst SNRIs, Venlafaxine has the best evidence. Augmentation of SSRI or quetiapine is recommended in the context of marked agitation. Trazodone 50mg-100mg night, quetiapine or prazosin are recommended as augmentation strategies if insomnia is present. Mirtazapine is recommended as 4th line treatment.

• 145. PTSD AND COMORBIDITIES content PTSD and Depression: [Rosen et al., 2020]

• 146. Residual symptoms like insomnia and hyperarousal often persist in PTSD, overlapping with depression. Combining medications with psychotherapies shows limited benefit for PTSD but improves comorbid depression. Antidepressants may be added to trauma-focused therapies for significant comorbid depression, particularly SSRIs like paroxetine, which show positive outcomes in both PTSD and depressive symptoms. Treating PTSD first can reduce depressive symptoms, but depression-focused treatments do not reduce PTSD. Ketamine has shown promise, reducing hospital stays in comorbid PTSD and depression by 70%. CPT and Prolonged Exposure are primary therapies, with antidepressants added for severe comorbid depression. Future strategies aim for personalized approaches, exploring treatment sequencing, combinations, and biomarkers. PTSD and Substance Use Disorder: Approximately 30-60% of individuals with PTSD also have a co-occurring Substance Use Disorder (SUD), highlighting a significant overlap between these conditions. PTSD and Substance Use Disorder (SUD) comorbidity likely involves overlapping neurobiological mechanisms driven by self-medication and combined psychological and physiological effects of trauma and substance use. [María-Ríos & Morrow, 2020] Integrated treatment combining trauma-focused psychotherapy, like Cognitive Processing Therapy (CPT) or Prolonged Exposure (PE), with medications such as naltrexone for Alcohol Use Disorder (AUD) or buprenorphine for Opioid Use Disorder (OUD) has shown strong support. [Back et al., 2024] Anticonvulsants (e.g., Topiramate, Zonisamide): Topiramate has shown potential for reducing both alcohol use and PTSD symptoms when combined with trauma-focused therapies like Prolonged Exposure (PE). [Batki et al., 2014] Ongoing trials are examining the efficacy of topiramate combined with PE to enhance treatment completion and reduce PTSD and alcohol use symptoms.

• 147. Adrenergic Modulators (e.g., Prazosin, Doxazosin): Clinical trials in veterans with PTSD and AUD have shown mixed results, with both active drugs and placebo conditions leading to improvements in symptoms. [Back et al., 2023] Future studies are focusing on subgroups (e.g., patients with high pretreatment blood pressure or severe withdrawal symptoms) to determine potential benefits. Selective Serotonin Reuptake Inhibitors: While SSRIs are FDA-approved for PTSD, their effects on SUD outcomes are inconsistent. Paroxetine has shown some efficacy in reducing PTSD symptoms, but less impact on substance use outcomes when used alone. They may still be useful as part of combined treatment, particularly for managing depressive symptoms that co-occur with PTSD and SUD. Opioid Use Disorder (OUD) Medications: Buprenorphine and methadone, when combined with PE or other trauma-focused therapies, have shown promise in managing PTSD symptoms in OUD patients. Early findings indicate that trauma-focused psychotherapy can be integrated effectively with OUD medications, helping to reduce trauma symptoms while maintaining addiction recovery. [Peck et al., 2023] Oxytocin: Oxytocin, a neuropeptide with anxiolytic and prosocial effects, is being explored as an adjunct to Cognitive Processing Therapy (CPT) for comorbid PTSD/AUD. In ongoing trials, intranasal oxytocin is administered before therapy sessions to enhance the therapeutic process, potentially improving outcomes for both PTSD and alcohol use. [Horn et al, 2024]. Naltrexone for Alcohol Use Disorder (AUD): Naltrexone has demonstrated effectiveness in reducing alcohol use severity when combined with trauma-focused treatments, such as PE or CPT.

• 148. The "Project Harmony" study found that PE combined with naltrexone produced the best long-term alcohol-related outcomes compared to supportive counselling or placebo combinations. [Hien et al., 2024] Psychedelic-Integrative Therapies (e.g., MDMA): Psychedelic-assisted therapy, particularly with MDMA, is being investigated for its potential to facilitate trauma processing while reducing substance cravings. An Australian study is examining MDMA combined with Concurrent Treatment of PTSD and Substance Use Disorders Using Prolonged Exposure (COPE) therapy for PTSD and AUD, aiming to improve PTSD symptoms and alcohol use outcomes. [Morley, 2024] PTSD and Sleep Disorders The interaction between PTSD and sleep disorders suggests a shared underlying mechanism, primarily driven by noradrenergic dysregulation and REM sleep disruption, creating a self-sustaining cycle of arousal, sleep fragmentation, and impaired emotional processing. [Lancel et al., 2021] Sleep disturbances contribute significantly to the development, maintenance, and severity of PTSD. Common Sleep Disorders: Obstructive Sleep Apnea (OSA) affects 40-90% of individuals with PTSD, leading to frequent oxygen desaturations and arousals, contributing to sleep fragmentation. Insomnia and Nightmares are common, exacerbating hyperarousal and perpetuating a cycle of disturbed sleep and PTSD symptoms. Periodic Limb Movement Disorder (PLMD) is observed in 33% of PTSD patients, causing frequent arousals. Sleep Paralysis and parasomnias, including confusional arousals, night terrors, and REM sleep behaviour disorder-like events, are also prevalent, disrupting both REM and non-REM sleep phases. Pathophysiological Mechanisms Linking Sleep Dysfunction and PTSD: Noradrenergic Hyperactivity: Hyperactive projections from the locus coeruleus (LC) play a key role in both PTSD and sleep disturbances, contributing to a state of heightened arousal and disrupted REM sleep.

• 149. Reciprocal Effects: Trauma-related hyperarousal can worsen OSA by promoting disordered breathing, while untreated OSA may increase the risk of PTSD due to ongoing sympathetic overactivity and sleep disruption. REM Sleep Disruption: Given that many OSA events occur during REM sleep, the ability of the brain to process negative emotions during this phase is likely impaired, reinforcing both PTSD symptoms and sleep dysfunction. Evaluation of Sleep Dysfunction in PTSD: Evaluation should cover trauma-related sleep triggers, circadian rhythm issues (e.g., in shift workers), parasomnias, and OSA. Screening tools like the Nightmare Disorder Index (NDI) and polysomnography (PSG) are helpful for accurate assessment. Non-Pharmacological Interventions: CBT for Insomnia (CBT-I) has the strongest evidence for improving sleep in PTSD. It focuses on sleep hygiene, relaxation training, and cognitive therapy. Imagery Rehearsal Therapy (IRT) is effective for treating nightmares, while exposure to trauma-related triggers can reduce sleep-related anxiety. Weighted blankets and other safety-promoting measures can aid relaxation, while interventions like Continuous Positive Airway Pressure (CPAP) effectively treat OSA. Pharmacological Interventions: [Lancel et al., 2021] Prazosin, an alpha-1 receptor antagonist, is the most supported medication for reducing nightmares and improving sleep. Sedating antipsychotics and antidepressants may help but require monitoring for side effects. Benzodiazepines are discouraged due to their risks, including worsening PTSD symptoms and potential for addiction. PTSD and Psychosis: Lifetime PTSD rates are higher in individuals with psychotic disorders (30%) than in the general population (7.8%). The actual rates may be underestimated due to underreporting in patients with serious mental illness. [Hardy & Mueser, 2017]

• 150. Pathophysiology: The link between trauma, PTSD, and psychosis involves multiple pathways [Hardy & Mueser, 2017] Childhood adversity leading to psychosis Trauma resulting from psychosis or involuntary treatments Trauma-induced psychosis PTSD and re-traumatisation exacerbating psychosis. Shared mechanisms include dissociation, intrusive symptoms like hallucinations and delusions, and negative symptoms such as withdrawal, often overlapping with PTSD's emotional numbing. Neurobiological, genetic, and symptom differences indicate that PTSD with secondary psychotic features (PTSD-SP) may be a distinct subtype. [Compean & Hamner, 2019] Dysregulation in the stress response and alterations in the dopamine system are thought to contribute to the comorbidity. Treatment: [Compean & Hamner, 2019] Evidence-based psychotherapies such as cognitive processing therapy (CPT), prolonged exposure (PE), and EMDR are recommended for PTSD, including PTSDSP. However, clinicians often hesitate to use them due to concerns of exacerbating psychotic symptoms. Despite concerns, research shows that these therapies do not worsen symptoms and are effective in managing comorbid PTSD and psychosis. Second-generation antipsychotics (SGAs), mainly risperidone and quetiapine, have been explored as adjunctive treatments. Risperidone has shown modest efficacy, particularly in reducing psychotic symptoms in PTSD-SP, but the evidence remains limited due to a scarcity of high-quality randomized controlled trials. SSRIs are the first-line treatment for PTSD but may be less effective in cases with comorbid psychosis. PTSD and ADHD: PTSD and ADHD often co-occur, leading to more severe psychiatric symptoms, impaired psychosocial functioning, and complex treatment requirements. [Spencer AE, Faraone SV, Bogucki OE, Pope AL, Uchida M, Milad MR, Spencer TJ, Woodworth KY, Biederman J. Examining the association between posttraumatic stress disorder and attention-

• 151. deficit/hyperactivity disorder: a systematic review and meta-analysis. J Clin Psychiatry. 2016 Jan;77(1):72-83]. Neurobiological mechanisms common to both disorders include prefrontal cortical (PFC) dysfunction and dopaminergic dysregulation, which contribute to deficits in attention, impulse control, and emotional regulation. Neurobiology of Attention Deficit Hyperactivity Disorder (ADHD) – A Primer PFC dysfunction disrupts top-down inhibition in both conditions, impairing emotional regulation in PTSD and executive functions in ADHD. Dopaminergic abnormalities also underlie impulsivity and reward processing issues, which are central to ADHD and contribute to PTSD’s hyperarousal and memory alterations. This shared dopaminergic dysfunction could explain why individuals with ADHD may be at an increased risk for developing PTSD following trauma exposure, as dopamine plays a central role in fear conditioning and stress responses. [Spencer et al, 2016]. Clinically, individuals with co-occurring PTSD and ADHD exhibit worse cognitive performance, greater impulsivity, and a higher risk of additional psychiatric comorbidities, such as substance use disorders (SUDs) and depression. [Antshel et al, 2016]. , [El Ayoubi, et al, 2021]. This combination complicates treatment and often results in poorer outcomes. The familial co-aggregation of the disorders suggests shared genetic risk factors, emphasising the need for early detection and intervention to prevent the worsening of symptoms. [Wendt et al.,2023]. Integrated treatment strategies are crucial, combining trauma-focused therapies with ADHD-specific interventions. Dopaminergic agents like methylphenidate and atomoxetine could be beneficial, given their role in enhancing PFC functioning and managing symptoms of hyperarousal and inattention [Torrisi et al., 2019]. Integrating trauma-focused therapies alongside psychostimulants may offer synergistic benefits by improving fear extinction and reducing symptom relapse. [Houlihan,2011]. Given the greater clinical severity and psychiatric comorbidity associated with this dual diagnosis, a comprehensive, phase-specific treatment plan is essential. Early management of ADHD can help reduce the risk of developing PTSD following trauma, improving overall clinical outcomes. Screening for ADHD among trauma-exposed individuals may enhance the effectiveness of PTSD prevention and treatment efforts. PTSD and Bipolar Disorder (BPAD) Bipolar disorder (BD) and PTSD frequently co-occur, with estimates suggesting that up to 50% of individuals with BD also meet the criteria for comorbid PTSD. [Russell et al., 2024]. This comorbidity is associated with worse clinical outcomes, including more severe depressive and manic symptoms, poorer sleep quality, and increased rates of

• 152. hospitalisations compared to those with BD alone. Individuals with both disorders often receive sedative medications more frequently, while lithium use is lower, particularly in those with multiple trauma exposures. [Russell et al., 2023]. Studies indicate that the prevalence of PTSD among bipolar patients is approximately 16%, which is twice the lifetime prevalence in the general population. [Otto et al., 2004]. Contributing risk factors include greater trauma exposure, the presence of additional Axis I disorders, and lower levels of social support and socioeconomic status. Currently, no randomised controlled trials (RCTs) have been conducted specifically for the treatment of comorbid BD and PTSD, and existing evidence is limited to observational studies and open-label trials. Pharmacological management is challenging due to the risk of triggering manic episodes or rapid cycling when using selective serotonin reuptake inhibitors (SSRIs) or other antidepressants. It is recommended to prioritise mood stabilisation before introducing antidepressants to mitigate this risk. [Hendriks & Goossens, 2022]. Studies suggest that lithium response rates are lower in patients with comorbid PTSD, while quetiapine shows some efficacy, although with more severe residual symptoms compared to BD alone. [Russell et al., 2023]. CONCLUSION content Posttraumatic Stress Disorder (PTSD) is a complex and heterogeneous disorder characterised by distinct phenotypes arising from alterations in neurocircuits regulating emotion, memory, and reactivity. The condition’s pathophysiology involves structural and functional brain changes in regions such as the amygdala, prefrontal cortex, and hippocampus, contributing to symptoms like intrusions, avoidance, mood disturbances, and hyperarousal. Effective diagnosis of PTSD requires recognition of its heterogeneity and frequent comorbidity with other psychiatric disorders, such as depression, substance use, and psychosis. This necessitates a broad diagnostic approach to avoid misattributing

• 153. symptoms solely to trauma, which could lead to misdiagnosis and inadequate care. The development of PTSD involves complex interactions between pre-trauma vulnerabilities, acute peritraumatic responses, and posttraumatic factors, reflecting a deeper biological adaptation to stress. The disorder’s persistence beyond one month signifies abnormal neurobiological responses rather than a normal adaptation to stress, emphasizing the importance of neurobiological insights for both diagnosis and treatment. Management requires phase-specific and individualised approaches that incorporate trauma-focused psychotherapies, pharmacotherapies, and potential neurobiological interventions. Treatments should target core symptoms and address co-occurring conditions to enhance outcomes. While therapies like neurofeedback, anti-inflammatory agents, and neuromodulation show promise, further research is necessary to determine their roles in treatment-resistant cases. Thus, PTSD is a multidimensional disorder that requires an integrated, evidence-based approach. Advances in personalised medicine and emerging interventions offer promising pathways for more effective treatment, emphasising the need for ongoing research to enhance recovery and functional outcomes. Get serious about psychiatry learning Join Academy by Psych Scene to access over 40 hours of in-depth, high-quality psychiatry courses that earn CPD points/CME credits. References Yehuda, R., Hoge, C. W., McFarlane, A. C., Vermetten, E., Lanius, R. A., Nievergelt, C. M., Hobfoll, S. E., Koenen, K. C., Neylan, T. C., & Hyman, S. E. (2015). Post-traumatic stress disorder. Nature reviews. Disease primers, 1, 15057. Benjet, C., Bromet, E., Karam, E. G., Kessler, R. C., McLaughlin, K. A., Ruscio, A. M., Shahly, V., Stein, D. J., Petukhova, M., Hill, E., Alonso, J., Atwoli, L., Bunting, B., Bruffaerts, R., Caldas-de-Almeida, J. M., de Girolamo, G., Florescu, S., Gureje, O., Huang, Y., Lepine, J. P., … Koenen, K. C. (2016). The epidemiology of traumatic event exposure worldwide: results from the World Mental Health Survey Consortium. Psychological medicine, 46(2), 327–343. Kessler, R. C., Chiu, W. T., Demler, O., Merikangas, K. R., & Walters, E. E. (2005). Prevalence, severity, and comorbidity of 12-month DSM-IV disorders in the National

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• 163. Wendt FR, Garcia-Argibay M, Cabrera-Mendoza B, Valdimarsdóttir UA, Gelernter J, Stein MB, Nivard MG, Maihofer AX; Post-Traumatic Stress Disorder Working Group of the Psychiatric Genomics Consortium; Nievergelt CM, Larsson H, Mattheisen M, Polimanti R, Meier SM. The Relationship of Attention-Deficit/Hyperactivity Disorder With Posttraumatic Stress Disorder: A Two-Sample Mendelian Randomization and Population-Based Sibling Comparison Study. Biol Psychiatry. 2023 Feb 15;93(4):362-369 Russell, S. E., Wrobel, A. L., Lotfaliany, M., Ashton, M. M., Kaur, R., Yocum, A. K., … & Turner, A. (2024). Trauma and comorbid post-traumatic stress disorder in people with bipolar disorder participating in the Heinz C. Prechter Longitudinal Study. Journal of affective disorders, 348, 275-282 Dr. Sanil Rege is a Consultant Psychiatrist and founder of Psych Scene and Vita Healthcare. He currently practices on the Mornington Peninsula.

• 164. Dr Sanil Rege

• 165. MBBS, MRCPsych, FRANZCP Dr. Sanil Rege is a Consultant Psychiatrist and founder of Psych Scene and Vita Healthcare. He has dual psychiatry qualifications from the United Kingdom and Australia. He currently practices on the Mornington Peninsula. His focus on combining psychiatry with principles of entrepreneurship has uniquely enabled him to not only contribute to the academic world through his several publications but also add value to the real world by establishing two successful enterprises in a short span of 6 years. He was appointed Associate Professor of Psychiatry at a prestigious Australian University at the age of 32 but left the role to focus on his passion of entrepreneurship in psychiatry. Psych Scene was co-founded to enhance psychiatry education, and Vita Healthcare was to provide the highest quality mental health care to the public. He is passionate about learning from multiple disciplines (Medicine, Psychiatry, Neurosciences, Accounting, Entrepreneurship, Finance and Psychology) with the aim of adding value to the world. By taking on multiple roles of a clinician, entrepreneur, father, educator, investor and MBA student, he recognises that personal development is a journey that needs to touch others lives for the better. He lives by the motto “All the knowledge in the world is not found in one academic discipline” and driven by curiosity. Dr. Sanil Rege is a Fellow of the Royal Australian and New Zealand College of Psychiatrists and Member of the Royal College of Psychiatrists (UK). He has practiced Psychiatry in the United Kingdom and throughout Australia. He has experience in the assessment and management of a broad range of psychiatric disorders, including psychosis, depression, anxiety, post-traumatic stress disorders, personality disorders, neuropsychiatric presentations and consultation-liaison psychiatry. Read More Download this article

• 166. As a Pro user you can download this article in a PDF format. After clicking, please wait for your PDF to download Download this article As a Pro user you can download this article in a PDF format. Download Hub’s materials for your personal use Get our articles as PDFs, download article images, and enjoy an ad-free experience for only $99/year. Generated with Reader Mode