A Systematic Review of Participant Diversity in Psychedelic-Assisted Psychotherapy Trials

Limited participant diversity in mental health intervention research perpetuates health disparities, a concern especially relevant to psychedelic-assisted psychotherapy (PAT). This systematic review of 21 randomized controlled trials of psilocybin- and MDMA-assisted therapies (total 1,034 participants) found that gender (100%) and race or ethnicity (76%) were frequently reported, while socioeconomic status was sometimes reported (57%) using varied measures. Sexual orientation (9.5%) and immigration status (4.8%) were rarely reported, and no studies reported gender identity. Black/African-American (12.2%) and Hispanic/Latino (7.2%) participants were significantly underrepresented compared to the US population and non-psychedelic clinical trials. MDMA trials enrolled more diverse samples than psilocybin trials. Analyses of treatment effects by sociodemographic variables were virtually nonexistent, highlighting the need for inclusive recruitment and rigorous reporting to improve generalizability.

Study at a glance

Abstract

Limited participant diversity in mental health intervention research perpetuates mental health disparities. This issue has become a particularly salient concern in studies of psychedelic-assisted psychotherapy (PAT), which is emerging as a promising mental health intervention. This systematic review evaluates the reporting, representation, and analysis of participant sociodemographic characteristics in randomized controlled trials (RCTs) of PAT. A total of 21 RCTs of psilocybin- and 3,4-methylenedioxy methamphetamine (MDMA)-assisted therapies (N = 1034) are summarized. Participants’ gender (100%) and race or ethnicity (76%) were frequently reported, with socioeconomic status (SES) sometimes (57%) reported using heterogeneous metrics. Sexual orientation (9.5%) and immigration status (4.8%) were rarely reported, and no studies reported gender identity. Compared to their representation in the US population and non-psychedelic clinical trials, Black/African-American participants (12.2%) and Hispanic/Latino participants (7.2%) were significantly underrepresented in PAT RCTs. MDMA trials enrolled more diverse participant samples than psilocybin trials. Analyses on treatment effects based on sociodemographic variables were virtually nonexistent. These findings underscore the need for more inclusive recruitment strategies, along with more rigorous reporting and analytic practices, to improve the generalizability of PAT research.