acute stress disorder

**Definition (DSM-5-TR):** Exposure to actual or threatened death, serious injury, or sexual violence (directly experienced, witnessed, learned about in a close relative/friend, or repeated exposure to aversive details, e.g., first responders). Requires ≥9 of 14 symptoms from five categories, lasting **3 days to 1 month** after the trauma: - **Intrusion:** recurrent distressing memories, nightmares, flashbacks, intense distress or physiologic reactivity to cues - **Negative mood:** persistent inability to experience positive emotions - **Dissociation:** altered sense of reality (e.g., derealization, depersonalization), inability to recall key aspects of the trauma (dissociative amnesia) - **Avoidance:** of memories, thoughts, feelings, or external reminders - **Arousal:** sleep disturbance, irritability, hypervigilance, poor concentration, exaggerated startle

Symptoms must cause clinically significant distress or impairment and not be due to a substance or medical condition, or better explained by brief psychotic disorder.

**ASD vs. PTSD vs. adjustment disorder (high-yield distinctions):** - **ASD:** 3 days to 1 month. Onset is within 1 month of the trauma. - **PTSD:** symptoms last >1 month. It requires a specific number of symptoms in each cluster: intrusion, avoidance, negative alterations in cognition/mood, and arousal/reactivity. Dissociation is not required. Delayed expression is a specifier. - **Adjustment disorder:** an identifiable stressor that need not be life-threatening. Symptoms begin within 3 months of the stressor and resolve within 6 months after the stressor ends. The full ASD/PTSD criteria are not met. - **Brief psychotic disorder:** psychotic symptoms (delusions, hallucinations, disorganized speech) lasting 1 day to 1 month. Consider it if psychosis is the main feature.

**Epidemiology/risk factors:** Higher risk with prior trauma, prior psychiatric illness, female sex, severe trauma (especially interpersonal violence such as assault or rape), and peritraumatic dissociation. ASD is a risk factor for later PTSD, but many patients with PTSD never met ASD criteria, so ASD is an imperfect predictor.

**Pathophysiology:** Fear-circuitry dysregulation: amygdala hyperreactivity, reduced medial prefrontal cortex inhibition, and hippocampal dysfunction (impaired contextualization of memory). Increased noradrenergic/sympathetic activity contributes to hyperarousal and strong memory consolidation. HPA axis changes (e.g., altered cortisol responses) are described in PTSD.

**Management:** - Ensure safety and meet basic needs. Provide supportive care and psychoeducation. - **First-line:** trauma-focused CBT (prolonged exposure, cognitive processing therapy, cognitive restructuring) started within the first month. It reduces progression to PTSD. - **Pharmacotherapy:** no medication is established to prevent PTSD. Short-term, symptom-targeted treatment may be used (e.g., prazosin for nightmares, or sleep aids), but benzodiazepines should be avoided because they may worsen outcomes and impair recovery. Single-session psychological debriefing is not recommended and may be harmful. SSRIs (sertraline, paroxetine) are first-line pharmacotherapy for PTSD, not ASD.

**Boards pearl:** A patient who was in a car accident or assaulted 2 weeks ago has nightmares, flashbacks, emotional numbness, and detachment, and avoids driving. The diagnosis is acute stress disorder. If the same symptoms persist at 6 weeks, the diagnosis is PTSD.