Are specific PTSD criteria associated with treatment outcome in traumatized veterans and police officers?

A significant proportion of patients with posttraumatic stress disorder (PTSD) do not respond sufficiently to trauma treatment. To date, it has not been clearly demonstrated which patients respond well and which do not. This study examined whether lifetime direct and interpersonal trauma exposure as well as the four distinct symptom clusters of PTSD were associated with treatment outcome. Participants were 262 veterans and police officers with PTSD (measured by the Clinician-Administered PTSD Scale for DSM-5, CAPS-5). Linear Mixed Model Analysis was performed to identify whether direct and interpersonal traumatization and the distinct symptom clusters of PTSD were associated with pre- to post-treatment changes in PTSD and general psychopathology according to the PTSD Checklist for DSM-5 (PCL-5) and Brief Symptom Inventory (BSI), respectively. Predictors were mean-centred to reduce multicollinearity in models with interaction terms. 51% Of participants reported clinically significant improvement for PTSD symptoms and 45% for symptoms of general psychopathology. Trauma characteristics and the severity of four PTSD symptom clusters pre-treatment were not associated with changes in total PTSD scores. Time showed consistent significant PTSD improvement across models. Higher pre-treatment symptom severity of cluster D of PTSD was associated with greater improvement in general psychopathology from pre- to post-treatment. There were two non-significant trends: higher severity of cluster C symptoms before treatment tended to be associated with smaller improvement in cluster E, and higher severity on cluster D with greater improvement of the same cluster D. Direct and interpersonal trauma exposure as well as pretreatment PTSD symptom cluster scores were not robustly related to overall PTSD treatment outcome. However, across all models, a significant reduction in PTSD symptoms over time was observed. To improve treatment efficacy, future research is recommended to explore individual symptoms and psychosocial contexts to achieve more personalized treatment approaches.