The stressor criterion in DSM-IV posttraumatic stress disorder: an empirical investigation.

BACKGROUND: The DSM-IV two-part definition of posttraumatic stress disorder (PTSD) widened the variety of stressors (A1) and added a subjective component (A2). The effects of the revised stressor criterion on estimates of exposure and PTSD in a community sample are evaluated.

METHODS: A representative sample of 2181 persons in southeast Michigan were interviewed about lifetime history of traumatic events and PTSD. The evaluation of the revised two-part definition is based on a randomly selected sample of events that represents the total pool of traumatic events experienced in the community.

RESULTS: The enlarged definition of stressors in A1 increased the total number of events that can be used to diagnose PTSD by 59%. The majority of A1 events (76.6%) involved the emotional response in A2. Females were more likely than males to endorse A2 (adjusted odds ratio = 2.66; 95% confidence interval 1.92, 3.71). Of all PTSD cases resulting from the representative sample of events, 38% were attributable to the expansion of qualifying events in A1. The identification of exposures that lead to PTSD were not improved materially by A2 however, events that did not involve A2 rarely resulted in PTSD.

CONCLUSIONS: Compared to previous definitions, the wider variety of stressors in A1 markedly increased the number of events experienced in the community that can be used to diagnose PTSD. Furthermore, A2 might be useful as a separate criterion, an acute response necessary for the emergence of PTSD, and might serve as an early screen for identifying a subset of recently exposed persons at virtually no risk for PTSD. The utility of A2 as a screen must be tested prospectively.