Clues Pointing TO This Diagnosis

Combat deployment (two tours) with exposure to life threat — meets Criterion A (exposure to actual/threatened death, serious injury, or violence), the required gateway for PTSD
Recurrent nightmares of the traumatic event — intrusion symptom (Criterion B), a hallmark reexperiencing feature
Flashbacks/reliving ("back in the same moment") — dissociative intrusion reactions under Criterion B
Dropping to the ground at a loud noise (startle to a trauma-like cue) — marked physiological reaction to reminders and exaggerated startle (Criteria B and E)
Avoidance of crowds and the news — persistent avoidance of external reminders (Criterion C)
Emotional numbness ("numbness where the feeling should be") — negative alteration in cognition/mood with inability to experience positive emotions (Criterion D)
Irritability and hypervigilance — marked alterations in arousal and reactivity (Criterion E)
Symptoms present and worsening over roughly four years — far exceeds the 1-month duration requirement (Criterion F) and reflects delayed help-seeking
Clear functional and interpersonal impairment (family strain, wife finding him under the table) — required clinically significant distress/impairment

Why It's NOT the Similar Diseases

NOT acute stress disorder — ASD is restricted to a 3-day to 1-month window after the trauma; Stanley's symptoms have persisted for years, so the diagnosis converts to PTSD
NOT adjustment disorder — adjustment disorder applies when the stressor is not a Criterion A trauma or when full PTSD criteria are unmet; Stanley had combat trauma and meets the full symptom profile
NOT major depressive disorder — although he has numbing and anhedonia, his symptoms are anchored to a traumatic event with intrusions, avoidance, and hyperarousal, which are not core MDD features (MDD can still be diagnosed separately if full criteria are met)
NOT panic disorder — his physiologic reactivity is cued by trauma reminders rather than unexpected, spontaneous panic attacks with anticipatory worry about future attacks
NOT obsessive-compulsive disorder — his intrusive experiences are trauma-linked memories, not ego-dystonic obsessions accompanied by compulsions unrelated to a traumatic event

Differential Diagnosis List

Acute stress disorder — ruled out by symptom duration well beyond 1 month
Adjustment disorder — ruled out by presence of a Criterion A trauma and full PTSD symptom criteria
Major depressive disorder — ruled out as the primary explanation because symptoms are trauma-anchored with intrusions/avoidance/hyperarousal
Panic disorder — ruled out because arousal is cued by trauma reminders, not unexpected panic attacks
Obsessive-compulsive disorder — ruled out by trauma-related intrusions without compulsions

Key Distinguishing Test

PTSD is a clinical diagnosis based on DSM-5-TR criteria after confirming Criterion A trauma exposure: at least 1 intrusion symptom, at least 1 avoidance symptom, at least 2 negative cognition/mood symptoms, and at least 2 arousal/reactivity symptoms, all lasting more than 1 month and causing significant distress or impairment.
Validated instruments support case-finding and severity tracking: the Primary Care PTSD Screen for DSM-5 (PC-PTSD-5) for screening and the PTSD Checklist for DSM-5 (PCL-5) for provisional diagnosis and monitoring.

Board Note

First-line treatment is trauma-focused psychotherapy—prolonged exposure (PE), cognitive processing therapy (CPT), or eye movement desensitization and reprocessing (EMDR)—which the 2023 VA/DoD guideline recommends over medication when available
Preferred pharmacotherapy is an SSRI (sertraline or paroxetine, both FDA-approved) or the SNRI venlafaxine; the 2023 VA/DoD guideline no longer includes fluoxetine among its recommended agents (insufficient evidence), whereas the 2025 APA guideline still lists fluoxetine among conditionally recommended medications—reflecting a genuine difference between guidelines
Benzodiazepines are recommended against—no evidence of benefit, risk of dependence, and possible worsening of outcomes; cannabis is also recommended against
For trauma-related nightmares, prazosin has a weak/conditional recommendation and imagery rehearsal therapy is an option; note the large PACT trial in veterans was negative, so response is variable
Screen with the PC-PTSD-5 in primary care and refer to mental health for trauma-focused psychotherapy; assess suicide risk and co-occurring depression and substance use, which are common
Here is the PC-PTSD-5 screening tool that would be used at the point of care to identify a patient like Stanley for further evaluation:
Ran calculation
Primary Care PTSD Screen for DSM-5 (PC-PTSD-5)
Screens for PTSD in primary care populations.
Have you ever experienced a traumatic event?
Examples of traumatic events include: a serious accident or fire; a physical or sexual assault or abuse; an earthquake or flood; a war; seeing someone be killed or seriously injured; having a loved one die through homicide or suicide.
Had nightmares about the event(s) or thought about the event(s) when you did not want to?
Tried hard not to think about the event(s) or went out of your way to avoid situations that reminded you of the event(s)?
Been constantly on guard, watchful, or easily startled?
Felt numb or detached from people, activities, or your surroundings?
Felt guilty or unable to stop blaming yourself or others for the event(s) or any problems the event(s) may have caused?
PC-PTSD-5 Score: 4
A score of 4 (positive at the usual cut point of 3) would prompt further diagnostic evaluation.

“Stanley’s Story”