More is not always better: 2 weeks of intensive cognitive processing therapy-based treatment are noninferior to 3 weeks.

Although there is mounting evidence that massed treatment for PTSD is both feasible and effective, many questions remain about the optimal length of intensive treatment programs (ITPs), as well as the role of adjunctive services, such as psychoeducation, mindfulness, and yoga. Our setting recently transitioned from a three-week ITP to a two-week program. Adjunctive services were reduced, but the amount of individual CPT between programs remained similar. The present study examined the effectiveness of a two-week ITP based on twice daily individual CPT sessions and evaluated the program's noninferiority to an established three-week ITP using a Bayesian analytical approach. Bayesian linear mixed regression models were used to explore PTSD and depression changes over time, as well as predictors of change. Noninferiority of the two-week ITP to a three-week ITP was also established using a Bayes factor approach. Results indicate that program participants change meaningfully in both PTSD and depression severity over the course of treatment, and that changes in posttraumatic cognitions predict subsequent changes in these outcomes. Further, the two-week ITP can be considered noninferior to the three-week ITP in both clinical outcomes and overall satisfaction. In the context of intensive PTSD treatment, the content of the ITP appears to matter more than its overall length. Shorter programs have the potential to increase access and treatment capacity. Our findings demonstrate the importance of continuous and rigorous program evaluation. Limitations as well as future directions for research, such as identifying the most effective treatment components, are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).