Symptom structure of PTSD: support for a hierarchical model separating core PTSD symptoms from dysphoria

Background: As of yet, no collective agreement has been reached regarding the precise factor structure of posttraumatic stress disorder (PTSD). Several alternative factor-models have been proposed in the last decades. Objective: The current study examined the fit of a hierarchical adaptation of the Simms et al. (2002) dysphoria model and compared it to the fit of the PTSD model as depicted in the Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition (DSM-IV), a correlated four-factor emotional numbing, and a correlated four-factor dysphoria model. Methods: Data were collected using the Clinician-Administered PTSD Scale in a mixed-trauma sample of treatment-seeking PTSD patients (N=276). Results: All examined models provided superior fit to the three-factor model of DSM-IV. The hierarchical four-factor solution provided a better fit than competing models. Conclusion: The present study provides empirical support for a conceptualization of PTSD that includes a higher-order PTSD factor that encompasses re-experiencing, arousal, and effortful avoidance sub-factors and a dysphoria factor.