Psilocybin and alcohol use disorder: what a placebo-controlled trial found
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The question
Alcohol use disorder (a medical term for drinking that a person struggles to control, and that keeps causing problems in their life) is common and hard to treat. The medications we have help some people, but many keep drinking heavily.
Earlier small studies hinted that psilocybin (the active compound in "magic mushrooms"), given alongside therapy, might help. This trial, led by Michael Bogenschutz at New York University and the University of New Mexico, asked a sharper question: compared with a placebo, does psilocybin plus therapy reduce how often people drink heavily?
Who took part and what happened
The trial enrolled 95 adults with alcohol use disorder. Their average age was about 46. They were randomly split into two groups: 49 received psilocybin and 46 received diphenhydramine (an antihistamine, used here as an "active placebo", meaning it has noticeable effects so people can't easily tell they got a dummy pill).
It was a double-blind study: neither the participants nor the therapists were told who got which drug.
Everyone received 12 weeks of structured talk therapy (motivational enhancement therapy and cognitive behavioral therapy, which focus on motivation, triggers and practical coping skills). On top of that, each person had two long, supervised medication sessions, at weeks 4 and 8. The first psilocybin dose was 25 mg per 70 kg of body weight. The second was 30 or 40 mg per 70 kg, depending on how strong the first session had been.
The main measure was the percentage of heavy drinking days over the 32 weeks after the first session.
What they found
- Heavy drinking days: over the 32 weeks, people in the psilocybin group had heavy drinking days on 9.7% of days, on average. In the placebo group it was 23.6%. That is a difference of about 14 percentage points, and it was statistically significant.
- Drinks per day: at follow-up, the psilocybin group averaged about 1.2 drinks a day, compared with about 2.3 in the placebo group.
- Not drinking at all: in the last month of the study (weeks 33–36), 47.9% of the psilocybin group reported no drinking at all, compared with 24.4% of the placebo group.
- Safety: the study reported no serious adverse events among participants who received psilocybin. Blood pressure and heart rate went up temporarily during sessions.
Both groups improved, which is common in trials where everyone gets therapy and support. The psilocybin group improved more.
What this study does not tell us
- The blinding didn't really hold. About 94% of participants correctly guessed which drug they got, and so did most therapists. Knowing you got psilocybin may itself shape hopes and behavior.
- Smaller than planned. The COVID-19 pandemic stopped enrollment at 95 people. The original target was 180.
- Secondary results are exploratory. The researchers did not correct for testing many outcomes at once, so findings beyond the main one should be read with caution.
- Mostly self-report. Drinking was measured mainly by what people reported. Lab tests were available for only part of the group.
- A limited time frame and group. Follow-up lasted about 8 months after the first session. Most participants were non-Hispanic white.
- Clinical conditions. Participants were screened carefully and supported by trained therapists. Results may not apply to other settings.
Why it matters
This was one of the first randomized, placebo-controlled trials of psilocybin for alcohol problems. It found a meaningful drop in heavy drinking compared with an active placebo, with both groups getting the same therapy. That is a stronger kind of evidence than earlier open studies. It still needs to be repeated in larger trials, with better ways to handle the blinding problem, before anyone can say how well this approach works.
This is a summary of published research for general information. It is not medical advice. The study took place in a clinical research setting with medical screening and professional support.
Source: Bogenschutz MP, Ross S, Bhatt S, Baron T, Forcehimes AA, Laska E, Mennenga SE, O'Donnell K, Owens LT, Podrebarac S, Rotrosen J, Tonigan JS, Worth L (2022). Percentage of heavy drinking days following psilocybin-assisted psychotherapy vs placebo in the treatment of adult patients with alcohol use disorder: a randomized clinical trial. JAMA Psychiatry, 79(10), 953–962. doi:10.1001/jamapsychiatry.2022.2096 · PubMed · Full text
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