Post-Traumatic
Stress Disorder
A psychiatric disorder that develops after exposure to traumatic events involving actual or threatened death, serious injury, or sexual violence. Characterized by intrusive memories, avoidance, negative mood changes, and hyperarousal.
DSM-5-TR Diagnostic Criteria
Criterion A: Trauma Exposure
Exposure to actual or threatened death, serious injury, or sexual violence.
Criterion B: Intrusion
1+ required:
- • Recurrent distressing memories
- • Traumatic nightmares
- • Dissociative reactions (flashbacks)
- • Psychological distress to cues
- • Physiological reactions to cues
Criterion C: Avoidance
1+ required:
- • Avoidance of trauma-related thoughts/feelings
- • Avoidance of external reminders
Criterion D: Negative Mood/Cognitions
2+ required:
- • Inability to recall key trauma features
- • Negative beliefs about self/world
- • Persistent negative emotional state
- • Diminished interest in activities
- • Detachment from others
- • Inability to experience positive emotions
Criterion E: Hyperarousal
2+ required:
- • Irritable/aggressive behavior
- • Reckless/self-destructive behavior
- • Hypervigilance
- • Exaggerated startle response
- • Concentration problems
- • Sleep disturbance
Additional Requirements
Timing and functional impact
- • Symptoms persist >1 month
- • Functional impairment or significant distress
- • Not attributable to substance use or medical condition
Assessment Protocols
Validated tools for screening and severity tracking
PCL-5
PTSD Checklist for DSM-5-TR
Criterion-standard 20-item self-report measure corresponding directly to DSM-5-TR symptom criteria.
Cutoff ≥33 suggests probable PTSD; symptom cluster scores guide treatment planning
CAPS-5
Clinician-Administered PTSD Scale
Structured clinical interview providing categorical diagnosis and dimensional symptom severity.
Severity ratings 0-4 per symptom; diagnoses PTSD and identifies dissociative subtype
PC-PTSD-5
Primary Care PTSD Screen
Brief 5-item screener for use in primary care and emergency settings.
3+ 'yes' responses suggests need for full PTSD assessment
DES
Dissociative Experiences Scale
Assesses dissociative symptoms often present with PTSD (derealization, depersonalization).
Mean score ≥30 suggests clinically significant dissociation
Causes & Etiology
Traumatic Events
- Combat exposure
- Sexual assault and intimate partner violence
- Serious accidents
- Natural disasters
- Childhood abuse
- Witnessing violence or death
Neurobiological
- Amygdala hyperactivity
- Prefrontal cortex hypoactivity
- Hippocampal volume reduction
- HPA axis dysregulation
- Norepinephrine and serotonin dysregulation
Risk Factors
- Prior trauma exposure (cumulative effect)
- Lack of social support post-trauma
- Peritraumatic dissociation
- Pre-existing anxiety or depression
- Female sex (2x higher prevalence)
- Genetic vulnerability (30-40% heritability)
Psychological Mechanisms
- Fear conditioning to trauma cues
- Impaired fear extinction
- Negative appraisals of trauma/self
- Experiential avoidance
- Memory fragmentation and intrusions
Scientific Sources
PCL-5 Validation
Weathers FW, Litz BT, et al. The PTSD Checklist for DSM-5-TR (PCL-5). National Center for PTSD. 2013.
DSM-5-TR Criteria
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). 2022.
Prolonged Exposure Efficacy
Powers MB, Halpern JM, et al. A meta-analytic review of prolonged exposure for posttraumatic stress disorder. Clin Psychol Rev. 2010;30(6):635-641.
Neurobiology of PTSD
Pitman RK, Rasmusson AM, et al. Biological studies of post-traumatic stress disorder. Nat Rev Neurosci. 2012;13(11):769-787.
EMDR Meta-Analysis
Bisson JI, Roberts NP, et al. Psychological therapies for chronic post-traumatic stress disorder in adults. Cochrane Database Syst Rev. 2013;(12):CD003388.
Comorbidity Epidemiology
Kessler RC, Sonnega A, et al. Posttraumatic stress disorder in the National Comorbidity Survey. Arch Gen Psychiatry. 1995;52(12):1048-1060.
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