What are the diagnostic criteria for post-traumatic stress disorder (PTSD)?

Diagnostic Criteria for Post-Traumatic Stress Disorder (PTSD)

PTSD diagnosis requires exposure to a traumatic event with symptoms persisting for more than one month that cause clinically significant functional impairment across four specific symptom clusters. 1, 2

Trauma Exposure Requirement

The patient must have experienced, witnessed, learned about, or had repeated exposure to details of traumatic events involving actual or threatened death, serious injury, or sexual violence. 1, 3, 4 This is the foundational criterion—without documented trauma exposure, PTSD cannot be diagnosed regardless of symptom presentation.

Four Required Symptom Clusters

1. Intrusion Symptoms (At Least 1 Required)

• Recurrent, involuntary, and intrusive distressing memories of the traumatic event 1
• Traumatic nightmares with content related to the event 1
• Dissociative reactions (flashbacks) where the person feels or acts as if the traumatic event is recurring 1, 4
• Intense or prolonged psychological distress when exposed to internal or external cues that symbolize the traumatic event 1, 3
• Marked physiological reactions to trauma reminders 4

2. Avoidance (At Least 1 Required)

• Avoidance of distressing trauma-related thoughts, memories, or feelings 1
• Avoidance of external reminders (people, places, conversations, activities, objects, situations) that arouse distressing memories, thoughts, or feelings about the traumatic event 1, 4

3. Negative Alterations in Cognition and Mood (At Least 2 Required)

• Inability to remember important aspects of the traumatic event (dissociative amnesia, not due to head injury, alcohol, or drugs) 1
• Persistent and exaggerated negative beliefs or expectations about oneself, others, or the world 1
• Persistent distorted cognitions about the cause or consequences of the traumatic event that lead to blaming self or others 1
• Persistent negative emotional state (fear, horror, anger, guilt, shame) 1
• Markedly diminished interest or participation in significant activities 4
• Feelings of detachment or estrangement from others 4
• Persistent inability to experience positive emotions (happiness, satisfaction, loving feelings) 1
• Restricted range of affect or sense of foreshortened future 3, 4

4. Alterations in Arousal and Reactivity (At Least 2 Required)

• Irritable behavior and angry outbursts (with little or no provocation), typically expressed as verbal or physical aggression toward people or objects 1
• Reckless or self-destructive behavior 1
• Hypervigilance 1, 3
• Exaggerated startle response 1, 4
• Problems with concentration 1, 4
• Sleep disturbance (difficulty falling or staying asleep, restless sleep) 1, 4

Temporal and Functional Criteria

Duration: Symptoms must persist for more than one month after trauma exposure. 5, 1, 3 If symptoms occur between 3 days and 1 month post-trauma, the diagnosis is Acute Stress Disorder, not PTSD. 6

Functional Impairment: The disturbance must cause clinically significant distress or impairment in social, occupational, or other important areas of functioning. 2, 3, 4 This distinguishes PTSD from normal stress reactions that do not require clinical intervention.

Exclusion: The disturbance cannot be attributable to the physiological effects of a substance (medication, alcohol) or another medical condition. 3, 4

Assessment Tools for Diagnosis

Gold Standard: The Clinician-Administered PTSD Scale (CAPS) is the gold standard diagnostic interview, assessing frequency and intensity of all 17 core symptoms. 1

Screening Tools:

• PTSD Checklist for DSM-5 (PCL-5) uses diagnostic criteria to help determine diagnosis and severity 7
• PTSD Reaction Index Brief Form for known trauma exposures 1
• Pediatric Traumatic Stress Screening Tool for primary care settings 1

Critical Diagnostic Pitfalls to Avoid

Underdiagnosis is common because many patients do not voluntarily report symptoms—direct screening is essential. 1 Ask specifically: "Has anything scary or concerning happened to you or your family?" followed by open-ended exploration of trauma exposure. 1

Do not rely solely on observable behaviors when assessing for PTSD, as most symptoms are internal (intrusive thoughts, avoidance, negative cognitions). 1 Direct inquiry about each symptom cluster is mandatory.

Screen for partial PTSD: Patients who meet some but not all criteria still experience significant distress and benefit from treatment. 1 Do not dismiss subthreshold presentations.

Assess for comorbidities: Depression, anxiety disorders, and substance use disorders are extremely common in PTSD and require concurrent treatment. 1, 7 Approximately 44% of PTSD patients have comorbid major depressive disorder. 4

Screen for sleep disorders: Many patients with PTSD-related sleep disturbance have undiagnosed obstructive sleep apnea, which requires separate treatment. 1, 7

Special Population Considerations

Children and adolescents: Parents and teachers often underestimate distress—screen children directly when age-appropriate. 1 Ask parents about sleep problems, appetite changes, clinginess, behavioral regression, and physical complaints without clear medical cause. 1

High-risk populations: Actively screen and monitor trauma-exposed individuals (combat veterans, assault victims, refugees, motor vehicle accident survivors) in the early period after trauma rather than waiting passively for one month. 1, 6 Early intervention shows moderate effects (Cohen's d = 0.28) in reducing PTSD symptom development. 1

Complex PTSD: Patients with prolonged or repeated trauma (childhood abuse, domestic violence, captivity) may require phase-based treatment with initial stabilization focusing on emotion regulation before trauma processing. 1