PsilOpioid: PsilOpioid: A Phase 2a placebo-controlled, randomised, proof of concept trial to investigate the feasibility, tolerability, and efficacy of psilocybin therapy in opioid use disorder (OUD).

Opioid addiction is a major public health challenge with rising death rates and over 140,000 people seeking treatment in the UK in 2023. Current treatments are limited, and many people relapse within a year after stopping using opioids. Research suggests that psilocybin (a compound in magic mushrooms) might be beneficial in treating addictions like alcohol and smoking. We will investigate if psilocybin combined with psychological support (‘psilocybin therapy’) can be helpful in treating people recovering from opioid addiction and how it might work. The study involves people who have recently stopped using opioids or opioid substitution therapy. Stage 1 of the study will test three doses of psilocybin, and the best dose will be chosen for further testing in stage 2. Eligible participants will attend the Hammersmith Hospital clinic to receive a single dose of psilocybin, with guided support from a therapist. Psychological support will also be provided at regular intervals before and for up to 3 months after receiving the psilocybin. Participants will be closely monitored throughout to understand the psychological effects and tolerability. At each study visit, we will measure opioid use, cravings, mental health and well-being using questionnaires and interviews. To understand brain effects, we will perform brain MRI scans before, and 7 days after the psilocybin. We will also contact participants after 6 months to monitor progress.Patient and public involvement: We are engaging individuals with lived experience of opioid addiction throughout the research process and within our team. This includes workshops for feedback on our research plan and study documents. Continuous feedback will help shape the study and ensure effective recruitment and communication of results.Results will be shared with scientists, doctors, policymakers, and the public through scientific reports, policy documents, media, and healthcare discussions.