Protocols and practices in psilocybin assisted psychotherapy for depression: A systematic review

Psilocybin-assisted psychotherapy (PAP) is a promising treatment option for depression, with randomized controlled trials (RCTs) providing preliminary support for its safety and efficacy. However, there is a lack of consistency across existing treatment protocols and psychotherapeutic approaches. The objective of this review is to summarize and compare current psychotherapy methods of PAP in treating depression and distress in life-threatening illnesses. We sought to comprehensively summarize published psychotherapy protocols from clinical trials to provide insights for future practices.

A systematic search of four databases (Embase, MEDLINE, PsycINFO, CINAHL) for data relating to psychotherapy protocols was conducted by two independent reviewers.

In total, our search identified 1869 articles; after removing duplicates, we screened 1107 articles. We included 70 articles in the full-text review and determined that 28 were eligible for the final review. All protocols include sessions before (preparatory) and after (integration) the psychedelic dosing session with supportive monitoring. However, there was substantial variability and inconsistencies in all other aspects of therapy protocols (e.g., duration and number of sessions, model of therapy). Additionally, significant limitations were identified in the frequent need for more clarity in the description of therapeutic approaches.

In published clinical trials, PAP has consisted of preparation, supportive dosing, and integration sessions. Beyond this basic framework, significant heterogeneity and lack of clarity were identified in reported psychotherapy protocols, meaning a validated and universally agreed upon protocol for PAP currently does not exist. Future studies should more clearly define and report psychotherapeutic components to identify the safest and most efficacious approaches to PAP.