Exclusion of participants based on substance use status: Findings from randomized controlled trials of treatments for PTSD

Abstract

Individuals with posttraumatic stress disorder (PTSD) are more than four times as likely as those without PTSD to have substance use disorder (SUD), making it critical to understand the interaction of substance use status and PTSD outcomes. Using the broader treatment literature, we examined PTSD treatment effects, with and without co-morbid SUD, by extending a published meta-analysis to include recent studies. From reports of 156 Randomized Controlled Trials (RCTs), we extracted exclusion criteria based on substance use and findings involving substance use as a predictor or outcome. Almost three-quarters of RCT designs excluded participants based on substance use status. Only 29.5% reported descriptive statistics characterizing substance use within the study sample and only 7.7% reported substance use-related outcomes. There was no clear relationship between exclusion criteria based on substance use and PTSD outcome or participant retention, suggesting either that SUD does not impede treatment effects, or that available studies lack sufficient data for these analyses. Importantly, no studies reported significant increases in substance use in the course of PTSD treatment. We conclude that patients with PTSD and co-morbid SUD have been largely neglected in PTSD RCTs; thus findings may not be fully applicable to those meeting criteria for both conditions.

Keywords: Alcohol; Clinical trial; Comorbidity; Drug; Multimorbidity; Pharmacotherapy; Psychotherapy; Substance use disorder.