PTSD factor structure differences between veterans with and without a PTSD diagnosis.

This study examined differences in posttraumatic stress disorder's (PTSD) factor structure between veterans with and without a PTSD diagnosis. An archival dataset of 378 trauma-exposed Canadian veterans (mostly men) was used. The sample was divided into participants who met DSM-IV criteria for PTSD (n=230) and those who did not (n=148), based on a structured diagnostic interview. Confirmatory factor analysis was conducted to determine which empirically supported four-factor PTSD model best fit the data: (1) King, Leskin, King, and Weathers' (1998) Emotional Numbing model of Reexperiencing, Avoidance, Emotional Numbing and Hyperarousal factors, or (2) Simms, Watson, and Doebbeling's (2002) Dysphoria model of Reexperiencing, Avoidance, Dysphoria, and Hyperarousal factors. Results indicated that both models fit slightly better in the No-PTSD group. A series of measurement invariance tests demonstrated that the two groups varied on all parameters with the exception of factor loadings. The PTSD-group had larger intercepts, factor means, and residual error variance, suggesting that these participants had greater PTSD severity but more measurement error associated with their PTSD ratings. This study contributes to our understanding of how a PTSD diagnosis impacts the structure of PTSD symptoms at the latent level.