Post-Traumatic Stress Disorder (PTSD) — Symptoms, Causes & Treatment | MyMedicPlus

Post-traumatic stress disorder (PTSD) is a trauma- and stressor-related mental disorder developing in some individuals after direct or indirect exposure to actual or threatened death, serious physical injury, or sexual violence. PTSD is classified separately from anxiety disorders in DSM-5-TR (as a trauma and stressor-related disorder) and from ICD-11, which additionally recognises complex PTSD (cPTSD) for prolonged, repeated interpersonal trauma. PTSD affects approximately 3.9% of the global population at any given time (lifetime prevalence: 10-20% in high-income countries) with substantially higher rates in specific high-risk populations: combat veterans and military personnel (20-30%), sexual assault survivors (30-50%), emergency responders and first responders (10-20%), refugees from conflict zones (30-50%), and survivors of severe childhood abuse or neglect. Women are approximately twice as likely as men to develop PTSD after equivalent trauma exposure — partly explained by the higher prevalence of high-risk trauma types (sexual violence) in women, and partly by biological differences in fear extinction and stress reactivity. The condition is frequently chronic and undertreated — median delay to receiving effective treatment is 12 years from symptom onset. PTSD has profound functional consequences: occupational impairment (inability to work in 50% of severe cases), relationship breakdown, social isolation, and markedly elevated suicide risk. The development of PTSD is not a sign of weakness or moral failure — it represents the persistence of a biologically normal fear response in the absence of safety signals, amenable to highly effective trauma-focused psychological therapies (EMDR, TF-CBT).

PTSD develops after exposure to DSM-5 Criterion A traumatic events — direct or indirect experience of actual or threatened death, serious injury, or sexual violence: combat and war; sexual assault, rape, and childhood sexual abuse; physical assault and violence; terrorism; natural disasters (earthquake, flood); serious accidents (road traffic collisions, aviation); witnessing the violent death or serious injury of others; and learning of violent or accidental death of a close family member or friend. Only 15-25% of individuals exposed to traumatic events develop PTSD — indicating that additional individual vulnerability factors determine who develops the disorder. Vulnerability factors: prior trauma exposure (especially childhood adverse experiences — ACEs; dose-response relationship with cumulative trauma); pre-existing mental health conditions (depression, anxiety, substance use); limited social support (the most powerful modifiable protective factor — social support reduces PTSD development by 40-50%); trauma severity, unpredictability, and interpersonal nature (rape and torture carry the highest conditional PTSD risk — 65-80%); peri-traumatic dissociation (emotional numbing or detachment during the trauma strongly predicts PTSD); acute stress response severity; female sex (approximately 2x increased risk at equivalent trauma exposure); and genetic polymorphisms in stress-response genes (FKBP5 regulating glucocorticoid receptor sensitivity; ADCYAP1R1 regulating fear extinction in women — estrogen-dependent). Neurobiological mechanisms: amygdala hyperreactivity (exaggerated fear conditioning and extinction failure); hippocampal volume reduction (impaired contextual fear discrimination — inability to recognise that current safety context is different from the trauma context); prefrontal cortical hypofunction (reduced inhibitory control over amygdala fear responses); and dysregulation of the HPA axis with CRF hypersecretion and complex cortisol abnormalities.

DSM-5-TR PTSD diagnosis requires all four symptom clusters to be present for more than 1 month after a Criterion A traumatic event, causing clinically significant distress or functional impairment. Cluster B — Intrusion symptoms (at least 1): spontaneous intrusive memories of the trauma (vivid, distressing, involuntary recollections); flashbacks (dissociative re-experiencing where the trauma feels as though it is currently happening — varying from brief intrusive images to complete dissociative episodes lasting minutes to hours where the person loses awareness of present surroundings); recurrent trauma-related nightmares (often exact replays of the traumatic event, waking the person in terror — responsible for much of the sleep disruption and sleep avoidance in PTSD); and intense psychological or physiological distress when exposed to trauma-related internal or external cues. Cluster C — Avoidance symptoms (at least 1): active avoidance of trauma-related thoughts, feelings, or memories; and active avoidance of external reminders (people, places, conversations, activities, objects, or situations associated with the trauma). Cluster D — Negative alterations in cognition and mood (at least 2): inability to remember important aspects of the trauma (dissociative amnesia); persistent and exaggerated negative beliefs about oneself or the world ('I am permanently damaged', 'The world is completely dangerous'); persistent distorted blame of self or others; persistent negative emotional states (fear, horror, anger, guilt, shame); markedly diminished interest or participation in significant activities; emotional numbing and detachment from others; and persistent inability to experience positive emotions (constricted affect, anhedonia). Cluster E — Alterations in arousal and reactivity (at least 2): irritable behaviour or angry outbursts; reckless or self-destructive behaviour; hypervigilance (scanning for threat in a normal environment — exhausting, prevents relaxation); exaggerated startle response to unexpected sounds or movements; concentration difficulty; and sleep disturbance (initial insomnia, middle insomnia, or nightmares disrupting restorative sleep).

PTSD is a clinical diagnosis based on DSM-5-TR or ICD-11 criteria — there is no blood test, imaging finding, or biomarker that confirms PTSD. A thorough clinical interview covering the traumatic event(s), symptom onset and duration, symptom cluster assessment, functional impairment, and differential diagnosis is essential. Validated screening and diagnostic tools: PTSD Checklist for DSM-5 (PCL-5): a 20-item patient-completed questionnaire rating each DSM-5 symptom on a 0-4 scale; total score above 33 indicates probable PTSD; widely used in primary care and military settings as an efficient screening tool. Clinician-Administered PTSD Scale for DSM-5 (CAPS-5): the gold standard for research and definitive clinical diagnosis — a structured clinician interview rating symptom frequency and intensity for all 20 DSM-5 symptoms; a CAPS-5 score of 35 or above indicates PTSD of at least moderate severity. Impact of Event Scale-Revised (IES-R): validated 22-item self-report tool assessing intrusion, avoidance, and hyperarousal subscales. Differential diagnosis is critical — several conditions overlap with or mimic PTSD and must be distinguished: acute stress disorder (identical symptom profile but duration below 1 month — resolves or progresses to PTSD); adjustment disorder (symptoms following a stressor that are disproportionate but do not meet full PTSD symptom cluster criteria); major depressive disorder (may co-occur with PTSD — diagnose both if criteria are independently met); borderline personality disorder (trauma history common, but emotional instability and identity disturbance are primary features); complex PTSD (cPTSD — ICD-11 diagnosis for PTSD plus pervasive disturbances in emotion regulation, identity, and relationships resulting from prolonged interpersonal trauma — childhood abuse, domestic violence, captivity); and dissociative disorders. Neuroimaging (fMRI, PET, structural MRI) reveals reduced hippocampal grey matter volume, amygdala hyperactivation to threat stimuli, and reduced prefrontal cortex activation in fear extinction tasks — these findings support the neurobiological understanding of PTSD but are not used clinically for diagnosis.

First-line trauma-focused psychological therapies are superior to medication and have the most evidence: Eye Movement Desensitization and Reprocessing (EMDR) — uses bilateral sensory stimulation during trauma memory recall to facilitate processing; 8-12 sessions produce significant symptom reduction in 77-90% of patients. Trauma-focused CBT (TF-CBT) including Prolonged Exposure (PE) and Cognitive Processing Therapy (CPT) — evidence-based, recommended by NICE, VA/DoD, and WHO. EMDR and PE are approximately equivalent in efficacy. Pharmacotherapy: sertraline (50-200mg) and paroxetine (20-50mg) are FDA-approved SSRIs for PTSD; venlafaxine (SNRI) is also effective. Prazosin reduces PTSD nightmares. Medication is second-line to trauma-focused therapy. Combined EMDR/CBT with SSRI is appropriate for severe or comorbid depression. Regular monitoring of treatment response, early detection of side effects, and ongoing assessment of disease progression are essential components of optimising patient outcomes over the long term. Treatment plans should be proactively reviewed and appropriately adjusted based on clinical response, patient-reported tolerability, changing patient circumstances, and continuously evolving evidence-based clinical guidelines. Meaningful shared decision-making between patients and their healthcare team, incorporating patient values and treatment preferences, consistently improves both treatment adherence and long-term outcomes.

PTSD has high comorbidity with major depression (50%), substance use disorders (self-medication with alcohol and drugs — 30-50%), panic disorder, and generalized anxiety disorder. Suicide risk is significantly elevated: 30% of PTSD patients have suicidal ideation; risk assessment is essential at every contact. Complex PTSD (cPTSD) from prolonged interpersonal trauma (domestic abuse, childhood neglect, captivity) includes additional features of emotional dysregulation, identity disturbance, and relationship difficulties. Physical health comorbidity: cardiovascular disease, autoimmune conditions, and chronic pain are more common in PTSD.

Early intervention after trauma: psychological first aid (practical support, safety, social connection) in the immediate aftermath does not prevent PTSD but reduces distress. Psychological debriefing immediately after trauma is not recommended (may increase PTSD risk). Watchful waiting for 1 month before committing to treatment is appropriate for most, as many cases resolve spontaneously. Brief EMDR or TF-CBT within 1 month reduces progression to PTSD in high-risk individuals. Building social support, reducing alcohol use, and early recognition of symptoms enable earlier treatment.

Seek immediate emergency help (call 999/911 or go to an emergency department) if: you or someone else is in immediate danger of suicide or self-harm; or severe dissociation or complete loss of contact with reality occurs. Seek urgent mental health support (within 1-2 weeks) for: persistent nightmares and flashbacks lasting more than 1 month after a traumatic event; inability to work or maintain basic daily function due to trauma symptoms; marked withdrawal from all activities and relationships; or substance use that is escalating and clearly linked to managing trauma symptoms. PTSD is a recognised medical condition — seeking help is not a sign of weakness. Effective psychological treatments exist and have strong evidence. Your GP can refer you to a trauma-focused psychological therapist or community mental health team. Veterans, emergency service workers, and survivors of sexual assault have access to specialist PTSD services. Self-referral to IAPT (Improving Access to Psychological Therapies) in the UK is also possible for trauma-focused CBT or EMDR.