Feigning combat-related posttraumatic stress disorder on the personality assessment inventory.

This study examined whether individuals who were instructed on the Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV]; American Psychiatric Association, 1994) criteria for posttraumatic stress disorder (PTSD) could feign PTSD on the Personality Assessment Inventory (PAI; Morey, 1991). The study also investigated whether PAI indexes of symptom exaggeration, the Negative Impression Management (NIM) scale and the Malingering index, could identify individuals feigning PTSD. The diagnostic rule for PTSD (Morey, 1991, 1996) was applied to the profiles of a group of 23 veterans with combat-related PTSD and 23 male undergraduates instructed to malinger PTSD. Seventy percent of the student malingerers produced profiles that received diagnostic consideration for PTSD. The NIM cutting score (> or = 8) was highly effective in detecting simulation of PTSD but resulted in the misclassification of a large number of true PTSD cases. There were no significant differences in the overall efficiency of the test with various validity criteria. We discuss the implications of these findings for the use of the PAI in the diagnosis of combat-related PTSD.