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

Post-traumatic stress disorder (PTSD) is a psychiatric disorder that can develop following exposure to an actual or threatened traumatic event — such as assault, sexual violence, warfare, accidents, natural disasters, childhood abuse, medical trauma, or witnessing death or serious injury. PTSD is classified in the DSM-5 under 'Trauma- and Stressor-Related Disorders' and in the ICD-11 as a distinct diagnosis alongside complex PTSD (C-PTSD). It affects an estimated 6-8% of people at some point in their lives globally and 3-4% at any given time. While approximately 70% of the global population experiences at least one traumatic event, only 20% develop PTSD — vulnerability depends on trauma severity, prior trauma history, social support, and genetic factors. PTSD is characterised by four core symptom clusters: intrusion (flashbacks, nightmares), avoidance, negative alterations in cognition and mood, and hyperarousal. Symptoms must persist for more than 1 month and cause significant functional impairment. Without appropriate treatment, PTSD is frequently chronic — lasting years to decades.

PTSD develops when the normal stress response fails to terminate appropriately after threat exposure, leading to dysregulation of fear memory processing, the hypothalamic-pituitary-adrenal (HPA) axis, and autonomic nervous system. Traumatic events most strongly associated with PTSD: combat exposure and military trauma (military personnel have 10-30% PTSD rates); sexual assault and rape (highest conditional probability of PTSD — approximately 50% of victims develop PTSD); childhood physical and sexual abuse; domestic violence; motor vehicle accidents; life-threatening illness or medical procedures; and terrorism. Risk factors for developing PTSD: female sex (2x higher risk after equivalent trauma exposure); prior trauma history; childhood adversity; history of depression or anxiety; lack of social support immediately post-trauma; high peritraumatic dissociation; and low socioeconomic status. Neurobiological mechanisms: hyperactivation of the amygdala (fear processing centre) combined with reduced prefrontal cortex regulation, smaller hippocampal volume (impaired contextualisation of fear memories), elevated norepinephrine, and dysregulated cortisol (paradoxically low in PTSD — unlike typical stress response).

PTSD requires symptoms from all four clusters for at least 1 month. Intrusion symptoms (criterion B — at least 1 required): recurrent intrusive distressing memories of the traumatic event; recurrent traumatic nightmares; dissociative flashbacks (feeling the trauma is re-occurring); intense psychological distress or physiological reactivity to trauma cues. Avoidance (criterion C — at least 1): avoiding internal memories, thoughts, and feelings related to the trauma; avoiding external reminders (people, places, conversations, situations). Negative alterations in cognition and mood (criterion D — at least 2): inability to remember key aspects of the trauma; persistent negative beliefs about self, others, or the world; persistent distorted blame of self or others for the trauma; persistent negative emotions (fear, horror, anger, guilt, shame); markedly diminished interest in activities; feeling detached or estranged; persistent inability to experience positive emotions. Hyperarousal and reactivity (criterion E — at least 2): irritable or angry behaviour; reckless or self-destructive behaviour; hypervigilance; exaggerated startle response; difficulty concentrating; sleep disturbance. Complex PTSD (ICD-11): additional features of affect dysregulation, persistent feelings of worthlessness and shame, and difficulties in relationships — typically from prolonged or repeated trauma.

PTSD diagnosis is clinical — based on detailed trauma history, symptom evaluation, and application of DSM-5 or ICD-11 criteria. Validated screening tools: PTSD Checklist for DSM-5 (PCL-5, 20 items — score above 33 indicates probable PTSD); Clinician-Administered PTSD Scale (CAPS-5 — gold standard structured diagnostic interview); and Impact of Event Scale-Revised (IES-R). Primary care screening: PC-PTSD-5 (5-item screen — any 3 positive triggers full assessment). Timeline: acute stress disorder (ASD) covers similar symptoms within the first 30 days post-trauma; PTSD is only diagnosed after 1 month of symptoms. Differential diagnosis: adjustment disorder (less specific symptom pattern, milder functional impairment); major depressive disorder (significant symptom overlap — intrusion and hyperarousal distinguish PTSD); generalised anxiety disorder; substance use disorder (frequently comorbid); borderline personality disorder (shares emotional dysregulation particularly with C-PTSD). Comorbidities are the rule: 80% of PTSD patients have at least one other psychiatric diagnosis — depression (50%), anxiety disorders, substance use disorders, and suicidality are particularly prevalent.

Psychological treatments are first-line for PTSD. Trauma-focused cognitive behavioural therapy (TF-CBT): most extensively evidenced treatment, typically 12-16 sessions — involves trauma narrative processing, cognitive restructuring of maladaptive beliefs, and systematic reduction of avoidance. Prolonged exposure (PE): gradual, systematic confrontation of trauma-related stimuli and memories, reducing the conditioned fear response. Cognitive processing therapy (CPT): 12-session structured protocol focusing on challenging 'stuck points' — unhelpful beliefs about self, others, and the world formed from trauma. EMDR (Eye Movement Desensitisation and Reprocessing): trauma reprocessing while engaging bilateral eye movements or other bilateral stimulation — recommended by WHO and NICE as a first-line treatment equivalent to TF-CBT; typically 8-12 sessions. Pharmacotherapy (second-line or adjunct): sertraline (Zoloft) 50-200 mg/day — FDA-approved for PTSD; paroxetine (Paxil) 20-60 mg/day — FDA-approved; venlafaxine (SNRI) 150-300 mg/day — strong evidence in several trials. Prazosin (alpha-1 antagonist) 1-20 mg at night: evidence for reducing trauma-related nightmares. Medications are most useful when trauma-focused therapy is not immediately accessible, or for managing severe comorbid depression and anxiety. Single-session critical incident debriefing should NOT be used — evidence shows no benefit and possible harm.

PTSD without treatment frequently becomes chronic, persisting for years or decades. Major depressive disorder is comorbid in approximately 50% of PTSD patients and significantly worsens overall prognosis, increasing suicide risk and reducing treatment response. Substance use disorders (alcohol, cannabis, opioids) develop in 30–40% as a means of managing intrusive symptoms, hyperarousal, and emotional numbing — worsening the overall prognosis and complicating treatment delivery. Suicidal ideation and attempts are substantially elevated — 20–40% of individuals with PTSD experience suicidal ideation; careful risk assessment is essential at every clinical contact. Physical health consequences are significant: chronic pain syndromes, cardiovascular disease (approximately 2-fold elevated risk), autoimmune disorders, and metabolic disorders arise from prolonged HPA axis dysregulation and elevated cortisol. Social and occupational impairment is profound — relationship breakdown, unemployment, and social isolation are common. Complex PTSD (arising from prolonged or repeated trauma, including childhood abuse) additionally involves disturbances in emotional regulation, self-perception, and relationship function, requiring adapted treatment approaches.

Primary prevention: reducing trauma exposure through interpersonal violence prevention programmes and safety campaigns. Acute post-trauma support: structured psychological first aid — focusing on basic needs, social support, and calm; natural recovery is the norm (80% of trauma-exposed individuals do NOT develop PTSD). Active monitoring (watchful waiting) for 1 month after significant trauma is preferred over immediate psychological debriefing. Secondary prevention: trauma-focused CBT started within 1-3 months of traumatic events for those developing early PTSD symptoms substantially reduces chronic PTSD development. Protective factors that reduce PTSD risk: strong social support networks (single most important factor); perceiving the trauma as survivable; prior positive coping experiences; and rapid access to appropriate mental health support. Recovery for established PTSD: approximately 50% of untreated PTSD cases remit over 2-5 years; with evidence-based treatment, 60-80% achieve significant symptomatic improvement. Vaccination reduces Long COVID risk — a PTSD analogy: early social and psychological support after trauma reduces PTSD progression.

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 and emergency service workers have access to specialist PTSD services.