PTSD & Acute Stress Disorder

Post-traumatic stress disorder (PTSD) and acute stress disorder (ASD) are trauma- and stressor-related disorders that follow exposure to a catastrophic event. They share an almost identical symptom architecture; the central discriminator is timing — ASD is the early, transient reaction (3 days–1 month), while PTSD is the persistent disorder (>1 month). For NEET PG, the high-yield hooks are the duration criteria, the four symptom clusters, prazosin for nightmares, and SSRIs as first-line pharmacotherapy.

Definition & nosological placement

In DSM-5 both conditions were moved out of the "Anxiety Disorders" chapter into a new chapter: Trauma- and Stressor-Related Disorders (which also houses adjustment disorder, reactive attachment disorder and disinhibited social engagement disorder). The defining requirement is Criterion A — exposure to actual or threatened death, serious injury or sexual violence, via one of four routes:

1. Directly experiencing the event.
2. Witnessing it in person.
3. Learning it happened to a close family member/friend (must be violent or accidental).
4. Repeated/extreme exposure to aversive details (e.g., first responders, police handling child-abuse evidence).

High-yield: Exposure through electronic media, television, films or pictures does NOT count for Criterion A — unless the exposure is work-related. This is a classic distractor.

Feature	Acute Stress Disorder (ASD)	PTSD
Onset	Within 3 days of trauma	Symptoms may begin anytime; diagnosis after 1 month
Duration	3 days to 1 month	>1 month
Symptom count (DSM-5)	≥9 symptoms from a pooled list of 14	Must satisfy all 4 clusters (B, C, D, E)
Dissociation	Heavily weighted	Optional "with dissociative features" specifier
Prognosis	~50% progress to PTSD	Chronic in a substantial minority

High-yield: If trauma-related symptoms persist beyond 1 month, the diagnosis converts from ASD to PTSD. If symptoms appear and resolve within the first 3 days, no disorder is diagnosed (normal acute stress reaction).

The four PTSD symptom clusters (Criteria B–E)

PTSD requires symptoms from each of four clusters. A useful frame: "TRAUMA hits, you Avoid, your mood Sinks, and you stay Wired."

• B — Intrusion / Re-experiencing (≥1 symptom): recurrent involuntary memories, distressing dreams, dissociative flashbacks (the patient feels the event is recurring), intense psychological/physiological reactivity to cues.
• C — Avoidance (≥1 symptom): persistent avoidance of internal reminders (thoughts/feelings) or external reminders (people, places, conversations). This is the most specific cluster.
• D — Negative alterations in cognition & mood (≥2 symptoms): dissociative amnesia for the event, persistent negative beliefs ("I am bad", "the world is dangerous"), distorted blame, persistent negative emotional state, anhedonia, detachment, inability to feel positive emotions.
• E — Alterations in arousal & reactivity (≥2 symptoms): irritability/angry outbursts, reckless/self-destructive behaviour, hypervigilance, exaggerated startle, concentration problems, sleep disturbance.

Two additional gatekeeping criteria:

• Criterion F: duration >1 month.
• Criterion G: clinically significant distress/impairment, not attributable to substances or another medical condition.

High-yield mnemonic for clusters: "I AM Anxious" — Intrusion, Avoidance, negative Mood/cognition, Arousal.

Specifiers and special variants

• "With dissociative symptoms" — depersonalisation (feeling detached from oneself) or derealisation (world feels unreal).
• "With delayed expression" — full criteria not met until ≥6 months after the trauma.
• PTSD in children ≤6 years — a separate developmental subtype; symptoms may be expressed through repetitive trauma-themed play and frightening dreams without clear content.

Etiology & pathophysiology

Trauma is necessary but not sufficient — most exposed individuals (the majority) never develop PTSD, so vulnerability factors matter.

Risk factors:

• Pre-traumatic: female sex, prior psychiatric illness, childhood adversity, lower socioeconomic status, lower IQ, genetic loading.
• Peri-traumatic: severity and proximity of trauma, interpersonal/intentional trauma (assault, rape, combat) far more potent than impersonal trauma (natural disaster), peri-traumatic dissociation.
• Post-traumatic: poor social support, subsequent life stress.

High-yield: Among all trauma types, sexual assault / rape carries the highest conditional risk of developing PTSD.

Neurobiology (frequently tested):

System	Finding in PTSD	Direction
HPA axis	Cortisol	Low/blunted (paradoxically, unlike depression which is high)
Sympathetic / noradrenergic	Noradrenaline, CSF NA, α1 activity	Increased → basis for prazosin
Amygdala	Threat processing	Hyperactive
Medial prefrontal cortex / ACC	Fear inhibition	Hypoactive (failed top-down control)
Hippocampus	Volume	Reduced (memory/context deficits)

The model: exaggerated amygdala fear response + failed prefrontal extinction + impaired hippocampal contextualisation = a fear memory that cannot be extinguished. Heightened noradrenergic tone underlies hyperarousal, nightmares and startle — the rationale for the α1-blocker prazosin.

High-yield: PTSD is the classic disorder with LOW cortisol and HIGH noradrenaline, with enhanced dexamethasone suppression (more cortisol suppression than normal) — opposite to major depression.

Clinical features

• Flashbacks — vivid dissociative re-living, the hallmark intrusion symptom.
• Nightmares — replaying the trauma; a key prazosin target.
• Hyperarousal — exaggerated startle, insomnia, irritability, hypervigilance.
• Avoidance & emotional numbing — withdrawal from reminders, restricted affect, "survivor guilt".
• Dissociation — amnesia, depersonalisation, derealisation.
• High comorbidity: depression, substance use disorder, other anxiety disorders, and increased suicide risk.

Diagnostic approach

PTSD is a clinical diagnosis — there is no confirmatory laboratory or imaging test. Diagnosis follows DSM-5 criteria after a structured history.

Stepwise clinical flow:

1. Confirm Criterion A trauma → identify qualifying exposure.
2. Map the four symptom clusters (B intrusion, C avoidance, D mood/cognition, E arousal).
3. Time the symptoms → <1 month = ASD; >1 month = PTSD; <3 days = normal reaction.
4. Exclude mimics → substance use, head injury, medical causes, other psychiatric disorders.
5. Screen comorbidity & risk → depression, substance use, suicidality.

Screening / rating instruments (eponyms worth knowing):

• CAPS-5 (Clinician-Administered PTSD Scale) — the gold-standard structured diagnostic interview.
• PCL-5 (PTSD Checklist) — self-report screening.
• PC-PTSD-5 — brief primary-care screen.
• IES-R (Impact of Event Scale–Revised) — symptom severity.

High-yield: CAPS-5 is the diagnostic gold standard; PCL-5 is a screening (not diagnostic) self-report tool.

Management

Management is stepped: psychotherapy is first-line for the disorder overall, with pharmacotherapy added or used when therapy is unavailable, declined, or comorbidity demands it.

Psychotherapy — first-line and most effective

Trauma-focused psychotherapies have the strongest evidence and are preferred over medication when available:

• Trauma-focused CBT (TF-CBT) — includes prolonged exposure and cognitive processing therapy (CPT). First-line.
• EMDR — Eye Movement Desensitisation and Reprocessing (Francine Shapiro): trauma recall paired with bilateral saccadic eye movements. Strong evidence, recommended by NICE/WHO.
• Stress inoculation training and prolonged exposure are specific exposure-based techniques.

High-yield: TF-CBT and EMDR are the two trauma-focused psychotherapies with the best evidence and are first-line for PTSD.

Pharmacotherapy

Indication	Drug of choice	Notes
Overall first-line drug class	SSRIs	Sertraline & paroxetine are the only FDA-approved drugs for PTSD
SNRI alternative	Venlafaxine	Strong second-line evidence
Trauma-related nightmares / sleep	Prazosin (α1-blocker)	Targets noradrenergic hyperarousal
Comorbid depression / broad symptoms	SSRI/SNRI	Treat both
Augmentation (refractory, distinct from antidepressants)	Atypical antipsychotics (e.g., risperidone, quetiapine)	Limited/adjunctive

High-yield: Sertraline and paroxetine are the only two SSRIs FDA-approved for PTSD. SSRIs are first-line pharmacotherapy.

High-yield: Prazosin is the drug of choice for PTSD-related nightmares and sleep disturbance — it antagonises α1-adrenergic receptors, dampening the noradrenergic surge during REM sleep. (Note: some recent large trials questioned efficacy, but for NEET PG the linked answer remains prazosin.)

Drugs to AVOID:

• Benzodiazepines — not recommended; they do not treat core PTSD symptoms, impair extinction learning, worsen outcomes, and carry dependence risk in a population prone to substance misuse.
• Avoid mono-dependence on hypnotics.

High-yield: Benzodiazepines are contraindicated/ineffective in PTSD — a favourite "single best answer" negative.

Prevention and ASD management

• ASD: trauma-focused CBT reduces progression to PTSD; brief course of CBT is the intervention of choice.
• Psychological debriefing (single-session CISD) is NOT recommended — it does not prevent PTSD and may worsen outcomes. This is heavily tested.
• Early hydrocortisone and propranolol for secondary prevention remain experimental.

High-yield: Single-session critical incident stress debriefing is ineffective and potentially harmful — do not choose it as a preventive answer.

Complications

• Progression of ASD → chronic PTSD (~50%).
• Major depressive disorder (highest comorbidity), increased suicide risk.
• Substance use disorders (self-medication, especially alcohol).
• Other anxiety disorders, somatic symptoms, chronic pain.
• Occupational and relational disability; in children, developmental and attachment disruption.
• Self-destructive/reckless behaviour, dissociative phenomena.

Key differentials

Condition	Distinguishing point
Acute stress disorder	Same picture but duration 3 days–1 month
Adjustment disorder	Stressor is not of catastrophic Criterion-A severity (e.g., divorce, job loss); milder symptom set
Major depressive disorder	Lacks intrusion/avoidance tied to a specific trauma; cortisol high
Panic disorder / GAD	Anxiety not anchored to a discrete traumatic memory
OCD	Intrusions are ego-dystonic obsessions, not trauma re-experiencing
Specific phobia	Fear of a circumscribed object, no broad arousal/avoidance complex
Traumatic brain injury / post-concussion	Organic; explained by head trauma, neuro signs
Psychotic disorder	Flashbacks/dissociation misread as hallucinations — flashbacks are re-experiencing, not psychosis
Malingering / factitious	Secondary gain, inconsistent presentation (medicolegal context)

High-yield: Adjustment disorder vs PTSD hinges on Criterion A — adjustment disorder follows an ordinary life stressor; PTSD requires a life-threatening/sexual-violence level trauma.

Recently asked / exam angle

• Duration cut-offs: ASD = 3 days to 1 month; PTSD = >1 month; delayed expression specifier = onset ≥6 months after trauma. Pure recall questions.
• Drug of choice for nightmares in PTSD → Prazosin (mechanism: α1-adrenergic antagonist). Recurrent single-best-answer.
• First-line / FDA-approved drugs → Sertraline and Paroxetine (SSRIs).
• Best-evidence psychotherapies → TF-CBT and EMDR.
• Negative/exclusion stems: benzodiazepines are NOT first-line; psychological debriefing does NOT prevent PTSD; media exposure does NOT satisfy Criterion A.
• Neuroendocrine twist: PTSD has low cortisol + high noradrenaline + enhanced dexamethasone suppression — contrast with depression.
• Highest-risk trauma type → sexual assault.
• Image/clinical vignette: combat veteran or assault survivor with flashbacks, hypervigilance, nightmares >1 month → diagnose PTSD, start SSRI + trauma-focused therapy, add prazosin for nightmares.

Rapid revision

1. ASD = 3 days–1 month; PTSD = >1 month; <3 days = normal stress reaction.
2. DSM-5 puts both under Trauma- and Stressor-Related Disorders, not anxiety disorders.
3. Criterion A = exposure to death/serious injury/sexual violence; media/TV does not count (unless work-related).
4. Four clusters: Intrusion, Avoidance, negative Mood/cognition, Arousal (I AM Anxious).
5. Flashbacks = dissociative re-experiencing = hallmark intrusion symptom.
6. Sertraline & paroxetine = only FDA-approved (SSRIs); SSRIs are first-line pharmacotherapy.
7. Prazosin = drug of choice for trauma-related nightmares (α1-blocker).
8. Benzodiazepines are ineffective/contraindicated in PTSD.
9. TF-CBT and EMDR = best-evidence trauma-focused psychotherapies; first-line overall.
10. PTSD neurobiology: low cortisol, high noradrenaline, hyperactive amygdala, hypoactive mPFC, small hippocampus, enhanced dexamethasone suppression.
11. Single-session debriefing (CISD) does not prevent PTSD and may harm.
12. Sexual assault carries the highest risk of PTSD; CAPS-5 is the diagnostic gold standard.