Post-Traumatic Stress Disorder (PTSD) — Psychiatry (MBBS)

Definition

Key distinction: PTSD was moved out of the Anxiety Disorders category (DSM-III through DSM-IV) into the new Trauma- and Stressor-Related Disorders category in DSM-5.

Criteria A — Traumatic Event (Stressor)

1. Direct experience of the traumatic event
2. Witnessing the event in person (as it occurred to others)
3. Learning that the event occurred to a close family member or friend (must be violent/accidental in deaths)
4. Indirect exposure — repeated or extreme exposure to aversive details (e.g., first responders, police)

Note: Indirect exposure via media, television, movies, or pictures does NOT qualify unless it is work-related.

DSM-5 Diagnostic Criteria (A–H)

Criterion B — Re-experiencing (≥1 of 5)

1. Recurrent, involuntary, intrusive distressing memories
2. Recurrent distressing dreams/nightmares related to the event
3. Dissociative reactions (flashbacks) — feeling/acting as if the event is recurring (can be a complete loss of awareness of surroundings)
4. Intense/prolonged psychological distress to internal or external cues that symbolize the event
5. Marked physiological reactions to such cues (e.g., sweating, palpitations)

Criterion C — Avoidance (≥1 of 2)

1. Avoidance of distressing thoughts, feelings, or memories about the event
2. Avoidance of external reminders — people, places, conversations, activities, objects, situations

Criterion D — Negative Alterations in Cognition and Mood (≥2 of 7)

1. Dissociative amnesia — inability to remember an important aspect of the trauma
2. Persistent negative beliefs — "I am bad," "No one can be trusted," "The world is completely dangerous"
3. Distorted cognitions about cause/consequences — persistent self-blame or blaming others
4. Persistent negative emotional state — fear, horror, anger, guilt, shame
5. Diminished interest in significant activities (anhedonia)
6. Detachment/estrangement from others
7. Inability to experience positive emotions — emotional numbing (can't feel happiness, love)

Criterion E — Alterations in Arousal and Reactivity (≥2 of 6)

1. Irritable behavior and angry outbursts (verbal or physical aggression)
2. Reckless or self-destructive behavior
3. Hypervigilance
4. Exaggerated startle response
5. Concentration problems
6. Sleep disturbance — insomnia, difficulty maintaining sleep, restless sleep

Criterion F — Duration

• Symptoms of B, C, D, and E persist for > 1 month

Criterion G — Functional Impairment

• Clinically significant distress or impairment in social, occupational, or other functioning

Criterion H — Exclusion

• Not attributable to substances (e.g., alcohol, medication) or a general medical condition

Specifiers

With Dissociative Symptoms

• Depersonalization — feeling detached from one's own mind or body ("outside observer of oneself")
• Derealization — experiencing surroundings as unreal, dreamlike, distant, or distorted

With Delayed Expression

• Full DSM-5 criteria not met until ≥ 6 months after the event (though some symptoms may appear earlier)

Time-Based Classification

Epidemiology

• Lifetime trauma exposure in the USA: 50–89%
• Lifetime prevalence of PTSD: ~6.8% (USA); 12-month prevalence ~3.5%
• Women > Men: Lifetime prevalence — women 9.7%, men 3.6%
• Conditional prevalence after sexual assault: 65% (men), 46% (women)
• 17–33% of acute PTSD cases develop chronic PTSD

• 50% of PTSD patients do not seek treatment

• ~50% of adults with PTSD also meet criteria for Major Depressive Disorder (lifetime comorbidity ~90%)

Risk Factors

• Prior trauma history, childhood abuse
• Pre-existing anxiety, depression, or psychiatric disorders
• Female sex
• Genetic vulnerability (smaller hippocampal volume)
• Low socioeconomic status

• Severity, duration, proximity of exposure
• Peritraumatic dissociation

• Lack of social support
• Continued stress exposure
• Substance use

Clinical Features

Differential Diagnosis

Neurobiology

• Reduced hippocampal volume — may be a vulnerability factor rather than a consequence
• Amygdala hyperactivation — fear processing
• Hypoactivation of prefrontal cortex (PFC) — impaired extinction of conditioned fear
• HPA axis dysregulation — altered cortisol (often low, unlike depression where cortisol is high)
• Noradrenergic hyperactivity — underlies hyperarousal symptoms
• Fear extinction failure — core neurobiological mechanism

Assessment Tools

• CAPS-5 (Clinician-Administered PTSD Scale) — gold standard
• PCL-5 (PTSD Checklist for DSM-5) — self-report screening tool
• IES-R (Impact of Event Scale – Revised)

Treatment (Overview)

Psychotherapy (First-line)

• Trauma-Focused CBT (TF-CBT) — most evidence-based
• Prolonged Exposure (PE)
• Cognitive Processing Therapy (CPT)
• EMDR (Eye Movement Desensitization and Reprocessing)

Pharmacotherapy

• SSRIs — Sertraline and Paroxetine (only FDA-approved drugs for PTSD)
• SNRIs — Venlafaxine (effective)
• Prazosin — for PTSD-related nightmares (α1-blocker)
• Avoid benzodiazepines — no proven efficacy; risk of dependence and may worsen outcomes

Prevention

• Debriefing (psychological first aid) — evidence is mixed; routine single-session debriefing not recommended
• Early TF-CBT for those with acute stress symptoms
• Hydrocortisone and propranolol investigated as early preventive agents post-trauma

Key Exam Points (MBBS)

1. PTSD requires > 1 month duration; < 1 month = Acute Stress Disorder
2. 4 symptom clusters: Re-experiencing (B), Avoidance (C), Negative cognition/mood (D), Hyperarousal (E)
3. Criterion D (negative cognition/mood) is new in DSM-5 — not in DSM-IV
4. Flashbacks are dissociative reactions — reliving, not just remembering
5. Dissociative subtype (depersonalization/derealization) is a DSM-5 specifier
6. First-line pharmacotherapy: Sertraline or Paroxetine (SSRIs)
7. PTSD is a disorder of fear extinction failure — the amygdala-PFC axis
8. Women are 2–3× more likely to develop PTSD than men
9. Comorbidity with MDD is very high (~50% concurrent, ~90% lifetime)
10. ICD-11 criteria for PTSD are narrower than DSM-5 and identify a partially different patient subset