Objective: Recently, changes have been proposed to DSM-IV diagnostic criteria for posttraumatic stress disorder (PTSD) to refine the diagnosis because of concerns about its construct validity. Specifically, Spitzer et al. suggested narrowing the PTSD definition of trauma, specifying a symptom onset time frame after the trauma, and removing symptoms that overlap with other anxiety and mood disorders. We examined whether removing these overlapping anxiety/mood disorder symptoms resulted in differences (compared to the original DSM-IV PTSD criteria) in PTSD prevalence rates, diagnostic caseness, comorbidity and mental health–related disability, structural validity, and internal consistency. Method: Cross-sectional data were examined from the National Comorbidity Survey Replication (N= 5692), a multistage area household probability sample of US residents. PTSD diagnostic and symptom data and diagnostic data for other Axis I disorders were taken from the Composite International Diagnostic Interview. The study was conducted from February 2001 to December 2003.

Results: After removing PTSD symptoms overlapping with those of other anxiety and mood disorders, we found that the lifetime PTSD prevalence dropped only from 6.81% to 6.42%. Nevertheless, a sizeable proportion of PTSD-diagnosed persons would consequently lose PTSD caseness. Little difference was found between the criteria sets in diagnostic comorbidity and disability, structural validity, and internal consistency. Conclusions: These data provide evidence that PTSD’s overlapping anxiety and mood disorder symptoms are not responsible for PTSD’s prevalence, diagnostic comorbidity, and construct validity. Although the proposed symptom criteria revision would result in fewer symptoms by which to evaluate PTSD, it may not address questions raised about the diagnosis’ construct validity.