Effect of Written Exposure Therapy vs Cognitive Processing Therapy on Increasing Treatment Efficiency Among Military Service Members With Posttraumatic Stress Disorder: A Randomized Noninferiority Trial

Posttraumatic stress disorder (PTSD) occurs more commonly among military service members than among civilians; however, despite the availability of several evidence-based treatments, there is a need for more efficient evidence-based PTSD treatments to better address the needs of service members. Written exposure therapy is a brief PTSD intervention that consists of 5 sessions with no between-session assignments, has demonstrated efficacy, and is associated with low treatment dropout rates, but prior randomized clinical trials of this intervention have focused on civilian populations. To investigate whether the brief intervention, written exposure therapy, is noninferior in the treatment of PTSD vs the more time-intensive cognitive processing therapy among service members diagnosed with PTSD. The study used a randomized, noninferiority design with a 1:1 randomization allocation. Recruitment for the study took place from August 2016 through October 2020. Participants were active-duty military service members diagnosed with posttraumatic stress disorder. The study was conducted in an outpatient setting for service members seeking PTSD treatment at military bases in San Antonio or Killeen, Texas. Participants received either written exposure therapy, which consisted of 5 weekly sessions, or cognitive processing therapy, which consisted of 12 twice-weekly sessions. Participants were assessed at baseline and at 10, 20, and 30 weeks after the first treatment session. The primary outcome measure was PTSD symptom severity assessed with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5). Noninferiority was defined as the difference between the 2 groups being less than the upper bound of the 1-sided 95% CI-specified margin of 10 points on the CAPS-5. Overall, 169 participants were included in the study. Participants were predominantly male (136 [80.5%]), serving in the Army (167 [98.8%]), with a mean (SD) age of 34 (8) years. Eighty-five participants were randomly assigned to written exposure therapy, with 65 (76.5%) completing all treatment sessions, and 84 to cognitive processing therapy, with 47 (54.8%) completing all treatment sessions. Findings indicated that written exposure therapy was noninferior to cognitive processing therapy, with the largest difference in change in outcome between the treatment conditions of 3.96 points on the outcome measure. The 1-sided 95% CI upper limit was less than 10 points across time points in both groups and ranged from 4.