The Predictive Validity of the PTSD Checklist in a Nonclinical Sample of Combat-Exposed National Guard Troops

After returning from an extended combat deployment to Iraq, 348 National Guard soldiers were administered the PTSD Checklist (PCL-M), and the Beck Depression Inventory II (BDI-II) followed, on average, 3 months later by structured diagnostic interviews including the Clinician-Administered PTSD Scale (CAPS) for the Diagnostic and Statistical Manual of Mental Disorders (4th ed.). There were 6.5% of the soldiers who met diagnostic criteria for posttraumatic stress disorder (PTSD) based on structured interview. The predictive validity of the PCL was examined and contrasted with the predictive validity of the BDI-II in identifying soldiers meeting CAPS diagnosis for PTSD. The best identified PCL cut scores produced between 65% and 76% false positive errors when used as the sole source for identification of enduring PTSD. Comparison of prediction between the PCL and the BDI-II in identifying PTSD suggested that both instruments may be operating through tapping generalized distress rather than specific aspects of the disorder.