Using Client Narratives to Identify Predictors of Outcome in Written Exposure Therapy and Cognitive Processing Therapy

Abstract

Written exposure therapy (WET) is a brief, five-session treatment for posttraumatic stress disorder (PTSD) that aims to improve access to care. WET has been demonstrated to be an efficacious PTSD treatment with lower rates of dropout and noninferior PTSD symptom outcome compared to cognitive processing therapy (CPT), a 12-session, gold-standard treatment. To identify predictors of treatment outcome in both WET and CPT, the current study examined the content of participants’ written narratives. Participants were 123 adults with PTSD who were randomly assigned to receive WET (n = 61) or CPT (n = 62). The Change and Growth Experiences Scale (CHANGE) coding system was used to code all available narratives in both treatment conditions for variables hypothesized to be relevant to therapeutic change. Linear regression analyses revealed that in WET, higher average levels of accommodated (healthy, balanced) beliefs and an increase in accommodated beliefs from the first to the final impact statement predicted better PTSD symptom outcome at 12 weeks postrandomization. In CPT, higher average levels of overgeneralized and accommodated beliefs and lower levels of avoidance expressed in the narratives predicted better PTSD outcome. There were no significant predictors of outcome in analyses of change from the first to final impact statement in CPT. These findings add to research identifying predictors of change in WET and CPT by highlighting the importance of low avoidance in CPT and of trauma-related cognitions in both CPT and WET, even though WET is a brief written intervention that does not explicitly target cognitive change.