Confirmatory factor analysis of the Clinician-Administered PTSD Scale: Evidence for the dimensionality of posttraumatic stress disorder

The Clinician-Administered PTSD Scale (CAPS; Blake et al., 1990) is a structured interview that assesses the 17 key symptoms of posttraumatic stress disorder (PTSD) as established in the Diagnostic and Statistical Manual of Menial Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994). CAPS data from 524 treatment-seeking male military veterans were submitted to confirmatory factor analysis to test a series of nested models reflecting alternative representations of PTSD dimensionality: (a) a 4-factor, 1st-order solution; (b) a 2-factor, higher order solution; (c) a single-factor, higher order solution; and (d) a single-factor, Ist-order solution. The model of best fit was the 4-factor, Ist-order solution, containing moderately to highly correlated yet distinct Ist-order factors corresponding to the reexperiencing, effortful avoidance, emotional numbing, and hyperarousal aspects of PTSD. Implications for theory, assessment, and future research are presented in this article.