Unraveling PTSD: Symptom Cluster Change During and 1 Year after Veterans’ Residential PTSD Treatment.

Objective: Although treatment of posttraumatic stress disorder (PTSD) is effective in reducing symptom severity, remission rates are low. One potential underlying reason for treatment ineffectiveness is differential response of specific PTSD symptom clusters. Using data from a national Veterans Affairs (VA) residential PTSD treatment cohort, we conducted a longitudinal study to examine changes in Diagnostic and Statistical Manual of Mental Disorders, fifth edition PTSD symptom clusters from admission to 1-year follow-up. Method: PTSD symptom data were analyzed from a national cohort of veterans who completed VA PTSD residential treatment between October 2019 and September 2020 (n = 1,648; 13% women; median age 44.2 years). Endorsement (%) and severity (M[SD]) of PTSD clusters and individual symptoms were compared at admission, discharge, 4-month and 1-year follow-ups. Results: Large magnitude reductions in all four PTSD symptom clusters were observed from admission to discharge and both follow-ups; however, endorsement of all symptom clusters remained high. Intrusions (Cluster B) were the most highly endorsed at discharge and follow-up, whereas avoidance symptoms (Cluster C) were the least highly endorsed. Differential patterns of change were observed among the 20 individual PTSD symptoms; for example, flashbacks decreased during treatment, but increased to near admission levels by 1-year postdischarge. Conclusions: Results suggest that intrusive symptoms may be more resistant to residential treatment for PTSD and contribute to lower likelihood of treatment success. Future work is needed to examine differential treatment response for PTSD clusters, to inform the improvement of current and creation of novel treatment interventions, and to better address intrusive symptoms to maximize PTSD treatment gains.