The Efficacy of 90-Min Versus 60-Min Sessions of Prolonged Exposure for PTSD : A Randomized Controlled Trial in Active-Duty Military Personnel

Objective: Prolonged exposure (PE) therapy is a first-line posttraumatic stress disorder (PTSD) treatment, but the manualized 90-min session format constitutes a barrier to adopting PE in most settings because they use 60-min sessions for scheduling and billing. We examined whether 60-min PE sessions were as effective and efficient as 90-min PE sessions.

Method: In total, 160 active-duty military personnel with PTSD were randomized to 8–15 sessions of 60- or 90-min PE sessions and assessed pre- and posttreatment, and 3- and 6-month posttreatment, using the Clinician Administered PTSD Scale for Diagnostic and Statistical Manual for Mental Disorders, 5th edition [DSM-5] (CAPS-5). Participants were also assessed weekly during treatment using the PTSD Checklist for DSM-5 (PCL-5). A 60-min PE was hypothesized to be noninferior to 90-min PE based on preliminary studies.

Results: Using intent-to-treat analyses, the 95% CI for the difference between 60- and 90-min PE was less than the noninferiority margin (4.69 for the CAPS-5 and 7.38 for the PCL-5) at all three endpoints, suggesting that the efficacy of 60-min PE was noninferior to that of 90-min PE. Similarly, the rate of improvement per session for 60-min PE was noninferior to the rate for 90-min sessions for the PCL-5. Sensitivity analyses and Bayes factors were consistent with these results.

Conclusions: 60-min sessions of PE are noninferior to 90-min sessions with regard to both efficacy and efficiency. Thus, PE can be effectively delivered in shorter sessions, making it easier for behavioral health providers to implement within the military health system and in other mental health systems that use 60-min session appointments.