Support for a novel five-factor model of posttraumatic stress symptoms in three independent samples of Iraq/Afghanistan veterans: a confirmatory factor analytic study.

Background: A large body of confirmatory factor analytic studies of posttraumatic stress disorder (PTSD) symptoms has demonstrated the superiority of 4-factor dysphoria and emotional numbing models over the DSM-IV model. Recently, a novel 5-factor model, which separates the DSM-IV hyperarousal symptom cluster into distinct dysphoric and anxious arousal clusters, has been identified. However, little research has evaluated the best-fitting representation of PTSD symptoms in veterans of the Iraq and Afghanistan wars.

Methods: Confirmatory factor analyses were used to examine the factor structure of the PTSD Checklist in three independent samples of Iraq/Afghanistan veterans, including two community samples and a treatment-seeking sample.

Results: In all three samples, a novel model with five correlated factors reflecting symptoms of re-experiencing, avoidance, emotional numbing, dysphoric arousal, and anxious arousal provided a significantly better representation of PTSD symptoms than the DSM-IV, dysphoria, and numbing models. This model also showed evidence of "excellent fit" in the community samples according to empirically-defined benchmarks.

Conclusions: These findings suggest that PTSD symptomatology in both community and treatment-seeking Iraq/Afghanistan veterans may be best represented by a 5-factor model that separates the DSM-IV PTSD hyperarousal symptom cluster into distinct dysphoric arousal and anxious arousal clusters.