Comparing dropout from cognitive processing therapy versus prolonged exposure: Results from a randomized clinical trial.

objectiveDropout from evidence-based psychotherapies for posttraumatic stress disorder (PTSD; e.g., cognitive processing therapy [CPT] and prolonged exposure [PE]) remains a problem, with rates around 38%-51% in routine care settings. Research is needed to characterize predictors and timing of dropout to inform intervention efforts. Using data from the largest randomized controlled trial of CPT and PE to date, we examined the timing and predictors of dropout, including sociodemographic and psychosocial variables.

methodParticipants (N = 916; average age = 45.2; 79.9% male; 64.4% White) were U.S. veterans with PTSD who were randomized to receive PE (n = 455) or CPT (n = 461). Participants completed measures to assess demographic characteristics, PTSD symptoms, depression symptoms, quality of life, substance use, and treatment expectations and preferences. Dropout was defined as completing less than 12 sessions or completing fewer sessions than required based on the study protocol for early responders.

resultsDropout was significantly higher in PE (52.31%) than in CPT (45.77%). Survival analyses indicated better retention in CPT over time and suggested that this group difference became significant starting after Session 3. Slower reduction in PTSD symptom severity was related to dropout in CPT, but not in PE. Regression models showed that veterans who were younger, Black, and service-connected for PTSD were more likely to drop out.

conclusionsFew pretreatment predictors were associated with dropout, indicating the need for additional research, such as using more intensive, longitudinal methods with time-varying predictors during treatment, to elucidate reasons for dropout from these first-line trauma psychotherapies. (PsycInfo Database Record (c) 2026 APA, all rights reserved).