Validating Competing Structures of Post-Traumatic Stress Disorder

In the present study, we compare factor analytic models of post-traumatic stress disorder (PTSD) in terms of their fit and predictive utility with regard to external correlates such as comorbid diagnoses and other psychosocial outcomes. Competing models were compared and validated in an epidemiological dataset (N = 23,936). Confirmatory factor analyses (CFA) using models from prior literature with four through seven factor solutions were conducted. The seven factor Hybrid model, the six-factor Anhedonia model, and the six-factor Externalizing Behaviors model were the first, second, and third best-fitting models, respectively; however, the inconsistency of associations with external correlates and high factor intercorrelations suggested that higher-factor solutions may sacrifice parsimony for minimal gains in utility. The Anhedonia and Hybrid models’ separate Anhedonia and Negative Affect factors (a core difference from other models) demonstrated limited utility in differentially associating with distinct constructs under the internalizing umbrella. Anhedonia and Negative Affect also correlated highly with each other and nearly perfectly with the factors composed of their combined symptoms (e.g. the Externalizing Behaviors model’s Numbing factor), suggesting a "lumped" factor would be more parsimonious. The Externalizing Behaviors model showed predictive utility in accounting for externalizing comorbidities as well as differentiating among constructs within the internalizing spectrum; however, it lacked robust associations with externalizing behavioral outcomes such as frequency and quantity of drinking. These results give reason for concern that predominant structural models of PTSD may not be adequate for discriminating among or predicting functional outcomes related to PTSD symptomatology in trauma-exposed populations.