Improving Understanding of Cognitive Processing Therapy: Patterns and Predictors of Symptom Change

Survivors of military sexual trauma (MST) are more likely to develop posttraumatic stress disorder (PTSD) than survivors of combat and other sexual traumas. Cognitive processing therapy (CPT) has been identified as one of the most effective PTSD treatments, and is the only treatment validated for veterans with MST-related PTSD. Existing research has emphasized studying pre-post change in total PTSD symptom severity; however, PTSD symptoms may not respond equivalently to CPT. Specifically, re-experiencing symptoms may predict change in other symptom criteria, and sleep disturbance may remain even after successful treatment. Improved understanding of the patterns and predictors of symptom change may help optimize treatment outcome. The current dissertation investigated variability in symptom change during and after CPT using data from a randomized clinical trial of CPT for MST-related PTSD. In the first study, the pattern and temporal precedence of change in PTSD symptom criteria during and after CPT was assessed using three cross-lagged panel analyses. Hyperarousal, avoidance, and re-experiencing symptoms were entered as a predictor of subsequent change in the PTSD symptom criteria. A logarithmic pattern of change was found for all symptom criteria. Hyperarousal symptoms predicted and temporally preceded change in avoidance symptoms. No criteria predicted or temporally preceded change in hyperarousal or re-experiencing symptoms. The aim of the second study was to describe the prevalence of sleep disturbance in veterans with MST-related PTSD and identify predictors of change in sleep disturbance following CPT using a multiple regression analysis. Sleep disturbance was prominent at baseline affecting 100% of the sample. Clinically significant sleep disturbance remained prevalent at posttreatment regardless of total symptom improvement. Results of the multiple regression analysis did not identify significant predictors of change in sleep disturbance following CPT. PTSD symptoms did not resolve uniformly during and after CPT in this sample. Focusing on pre-post change in total PTSD symptoms likely ignores important differences in symptom change. Describing variability in symptom change can provide patients more realistic treatment expectations, and can allow providers to look for a characteristic pattern of change during treatment. Further research is needed to link elements of CPT to these patterns of symptom change.