(PS10-18) Factor Structure of PTSD in a Treatment-Seeking Sample of Veterans Exposed to Assaultive Military Sexual Trauma

Abstract Text: The latent structure of posttraumatic stress disorder (PTSD) has been under investigation since the diagnosis was introduced in 1980; structural findings vary as a function of trauma type and population with key implications for treatment and conceptualization. To date, the symptom structure of PTSD among individuals with Military Sexual Trauma specific to assault (MST-A; 14% of Veterans, Wilson, 2018) has not been extensively evaluated, limiting conceptual insight into the presentation of this uniquely high-risk population. Our research replicates and expands previous research on the latent structure of the PCL-5, a gold-standard self-report PTSD assessment though evaluating and contrasting four commonly utilized models: a DSM-5 four-factor model, and alternately proposed seven- (Armour et al., 2015), eight- (Duek et al., 2022), and four-factor PTSD-MDD bifactor models (Moring et al., 2019). Veterans (N = 223, 74% female, 67.7% White, age M = 42 years) presenting for MST-A mental health services at a Midwestern VA hospital PTSD specialty clinic completed the PTSD Checklist for DSM-5 (PCL-5) as part of a routine clinical evaluation procedure. Among the four models evaluated with confirmatory factor analysis, the PTSD-MDD bifactor model failed to converge and was no longer considered. The remaining three models yielded variable performance. The DSM-5 four-factor model demonstrated mixed acceptability of fit (χ2 = 400.77, χ2/df = 2.44, CFI =.91, TLI = .89, RMSEA = .08) with several metrics failing to reach minimum conventions suggestive of acceptable fit. In contrast, the seven- (χ2 = 286.6, χ2/df = 1.92, CFI = .95, TLI = .93, RMSEA = .064) and eight-factor models (χ2 = 253.09, χ2/df = 1.78, CFI = .96, TLI, .94, RMSEA = .059) yielded at least acceptable fit with the eight-factor model demonstrating increased evidence of good rather than acceptable fit. Model contrasts of the four- (AIC = 12003.54), seven- (AIC = 11920.06), and eight-factor models (AIC = 11900.56) added further support for superiority of the eight-factor model among veterans seeking care for military rape trauma. In the study sample, the DSM-5 proposed model demonstrated only some acceptable fit indices, while both 7 and 8 factor models performed in the acceptable range. Findings warrant replication but may point to the importance of considering the clinical importance of, and possibly targeting smaller clusters of symptoms to optimize treatment for MST-A .