Psychedelic-Assisted Group Therapy: A Systematic Review

Introduction

Psychedelic substances have a long history of group use in ceremonial and clinical contexts, and some landmark early studies of psilocybin were conducted in group settings. Trope and colleagues note that, despite this precedent and recent renewed scientific interest in classic psychedelics, contemporary clinical trials have largely used individual psychotherapy models and no published 21st-century clinical trial has tested a group therapy approach. Prior qualitative and quantitative findings from modern trials have suggested that social connectedness and interpersonal processes can be important mechanisms of change following psychedelic sessions, and many participants in individual trials request contact with other participants for support and integration. To address the gap in the literature, the investigators carried out a systematic review of English- and Spanish-language publications from 1900 to 2018 that described a group element during preparation, drug administration, or integration in psychedelic-assisted psychotherapy. The review excluded nonclinical ritual uses (for example, ayahuasca ceremonies) but included MDMA only when it was used alongside a classic psychedelic. The stated aim was to characterise published studies by clinical approach, experimental method, and outcomes, and to identify hypotheses and design considerations for future research on psychedelic-assisted group therapy and interpersonal functioning.