Can psilocybin help people quit smoking? What a small Johns Hopkins study found

Journal of Psychopharmacology · 2014

Photo: Emma Simpson on Unsplash

The question

Quitting smoking is hard. Most people who try, even with medication or counseling, are smoking again within months. In 2014 a team at Johns Hopkins University asked a simple first question: is it safe and practical to add psilocybin (the active compound in "magic mushrooms") to a standard quit-smoking program? And do people who go through it manage to stay off cigarettes?

This was a pilot study (a small, early test meant to see whether a bigger study is worth doing). It was not designed to prove that psilocybin works.

Who took part and what happened

Fifteen long-term smokers took part: 10 men and 5 women, average age 51. On average they smoked about 19 cigarettes a day, had smoked for about 31 years, and had already tried to quit about six times. All were screened and psychiatrically healthy.

Everyone followed a 15-week program. It included four weekly preparation meetings with cognitive behavioral therapy (CBT, a practical talk therapy that works on habits, triggers and thinking patterns), weekly support meetings after the quit date, and a meeting the day after each session.

The first psilocybin session was on the planned quit date (week 5), at a moderate dose (20 mg per 70 kg of body weight). A second session followed two weeks later and an optional third at week 13, usually at a higher dose (30 mg per 70 kg). Twelve people had three sessions and three had two. Sessions took place in a comfortable room with trained staff present the whole time.

The researchers did not rely only on what people said. They checked smoking with breath tests (carbon monoxide) and urine tests (cotinine, a breakdown product of nicotine).

What they found

• At 6 months: 12 of the 15 participants (80%) were confirmed as not smoking in the previous seven days. The authors note that typical success rates for other quit-smoking treatments are usually below 35%.
• At 12 months: in a later follow-up, 10 of 15 (67%) were confirmed abstinent.
• Long-term: 12 people came back for a final check, on average about 30 months (2.5 years) after their first session. At that point 9 of the original 15 (60%) were confirmed not smoking.
• How it felt: at 12 months, 13 of 15 participants (about 87%) rated their psilocybin sessions among the five most personally meaningful and spiritually significant experiences of their lives.

There were no serious medical problems that needed a doctor or medication. But sessions were not always easy. Six participants had periods of fear or anxiety during a session. Staff handled these with calm support. Blood pressure and heart rate went up temporarily during the sessions.

What this study does not tell us

• It was very small. Fifteen people is enough to spot a signal, not to draw firm conclusions.
• There was no comparison group. Everyone got psilocybin, and everyone knew it (an "open-label" design). So we can't tell how much of the result came from psilocybin and how much from the therapy, the attention, or people's own motivation.
• Lots of support. Participants had far more contact with staff than in a typical quit-smoking program. That alone may help.
• A narrow group. Almost all participants were white and highly educated, and they volunteered for a psilocybin study. They may not represent smokers in general.
• Clinical conditions. People were medically screened and supported by professionals. The results may not apply to other settings.

Why it matters

This small study suggested that psilocybin, combined with structured therapy, could be tested safely in people trying to quit smoking. The quit rates were high enough to justify larger, controlled studies, and those are now underway. Many participants also described their sessions as deeply meaningful, which researchers think may be part of how change happens. For now, though, these are early results from 15 people, not an answer.

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.

More research

Journal of Psychopharmacology · 2011Can one psilocybin session change personality? The 2011 study on opennessAfter one guided psilocybin session, volunteers who had a mystical-type experience showed more openness more than a year later.

Psychopharmacology · 2006Can psilocybin bring on a meaningful mystical experience? The 2006 Johns Hopkins studyTwo in three healthy volunteers ranked one guided psilocybin session among the most meaningful experiences of their lives.

Nature · 2024What happens in the brain on psilocybin? A close look with repeated brain scansSeven people, about 18 brain scans each: how psilocybin loosens the brain's networks, and what lingered weeks later.

JAMA · 2023A single psilocybin session for major depression, tested against a placeboIn 104 adults with depression, one 25 mg psilocybin dose with support lowered symptoms more than placebo for six weeks.

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