Psilocybin in the Treatment of Cannabis Use Disorder: A-Proof-of-Concept Study

Cannabis is the most commonly used psychoactive substance in Canada (Lowry \& Corsi, 2020). A sub-group of cannabis users develop a condition known as Cannabis Use Disorder (CUD), which is defined as a regular pattern of cannabis use that causes performance difficulty at work, school and relationships (Hasin et al., 2013). A review of current treatments available for CUD indicate the lack of a pharmacological and psychological treatment with high success rates, which highlights the importance of exploring potential psychosocial interventions for the treatment of CUD. Given the evidence of psilocybin's therapeutic potential in the treatment of substance use disorders (de Veen et al., 2017), we aim to conduct a study using psilocybin-assisted-psychotherapy in the treatment of CUD. The study aims to evaluate the feasibility, safety, tolerability and potential therapeutic effect of 2 doses \[25 mg\] of psilocybin administered as part of an 8-week Motivational Enhancement Therapy (MET) and supportive therapy. This trial will be the first to evaluate the potential treatment effects of psilocybin on symptoms of CUD.

NCT Number	NCT06225232
Lead Sponsor	McMaster University Collaborators: Center for Medicinal Cannabis Research, Peter Boris Centre for Addictions Research (PBCAR)
Conditions	Cannabis Use Disorder, Moderate, Cannabis Use Disorder, Severe
Enrollment	16 participants
Start Date	2025-03
Primary Completion	2026-03 (estimated)
Study Completion	2026-06 (estimated)
Updated on ClinicalTrials.gov	2025-03-19