(PS4-C62) Examining Therapeutic Processes as Predictors of Long-term Treatment Outcomes of Written Exposure Therapy and Cognitive Processing Therapy

Background: Multiple empirically supported, trauma-focused psychotherapies include cognitive restructuring and/or exposure components. Such treatments include Cognitive Processing Therapy (CPT) and Prolonged Exposure, as well as narrative-based treatments, such as Written Exposure Therapy (WET). A non-inferiority trial, conducted by Sloan and colleagues (2018), compared two treatments for posttraumatic stress disorder (PTSD): CPT, a 12-session, gold-standard treatment, and WET, a 5-session treatment with no between session assignments, developed to decrease barriers to care. Findings from the trial suggest that WET is noninferior to CPT in reducing PTSD symptoms. The current study examined predictors of long-term treatment outcomes of WET and CPT using clients’ written narratives from the noninferiority trial.

Methods: Participants were 126 treatment-seeking adults with a primary DSM-5 diagnosis of PTSD, who were recruited from the greater Boston community. Participants were randomly assigned to receive WET (n = 63) or CPT (n = 63).  Participants were included in the present study if they completed at least one written narrative and the 60-week post-randomization assessment (WET n = 57; CPT n=54). PTSD symptom severity was assessed with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) at pre-treatment, 6-, 12-, 24-, 36-, and 60-weeks post first treatment session. The CHANGE, a coding system of therapeutic change processes, was used to code all available narratives. Analyses included average scores of CHANGE variables across all narratives and scores for the last available narrative.

Results: Linear regression analyses showed that in WET, higher average levels of accommodated beliefs (balanced, healthy beliefs), as well as more accommodation in the last available narrative, predicted lower PTSD symptoms at the 60-week assessment. In CPT, higher average levels of negative emotions, positive self, and hope predicted better PTSD symptom outcome at 60-weeks. More negative emotion expressed in the last available written narrative also predicted better long-term outcomes in CPT.

Conclusions: Results illustrate that even a brief, trauma-focused intervention can facilitate healthy beliefs and adaptive processing of traumatic experiences (accommodation), which in turn predicts better long-term PTSD symptom outcomes. The findings also highlight the importance of emotional engagement in CPT and identifies two specific cognitive variables (a positive view of self and hope) that might help to sustain treatment gains. These findings add to research identifying processes of change in WET and CPT.