The latent structure of posttraumatic stress disorder: different models or different populations?

Factor analytic studies of the structure of self-reported posttraumatic stress disorder (PTSD) symptoms have consistently supported two 4-factor models; the "Dysphoria" and the "Emotional Numbing" model. The fit of both models has been satisfactory; however, it has been difficult to unequivocally determine which model is best. This study aimed to test the hypothesis that there is no single "correct" model, but rather that the models represent different subpopulations. A confirmatory factor 2-class mixture model was specified with the Dysphoria model in one class and the Emotional Numbing model in the other. This model was tested using data from participants from 4 trauma groups. This model fitted the data better than 1 and 2-class models of the Dysphoria, Emotional Numbing, and cross-factor loading model. It was concluded that the search for the "correct" model of PTSD based on the assumption of a single homogenous population may not be a worthwhile research endeavor.