Johnson · Journal of psychopharmacology (Oxford, England) 2014 · open-label pilot study · n=15

Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction.

Cited 924 times in the scientific literature.

Level 4 - case-series / case-control

Open-label uncontrolled pilot study (case series)

PubMed 25213996 · doi:10.1177/0269881114548296 · record verified 2026-08-30

What was done

An open-label pilot study evaluated psilocybin as an adjunct to a structured 15-week smoking cessation treatment protocol. Fifteen psychiatrically healthy nicotine-dependent smokers (10 males, mean age 51 years; smoking a mean of 19 cigarettes per day for 31 years with a mean of 6 prior quit attempts) received moderate (20 mg/70 kg) and high (30 mg/70 kg) doses of psilocybin. Abstinence was measured using self-reports and biological markers.

What was found

At the 6-month follow-up, 12 of 15 participants (80%) achieved seven-day point prevalence smoking abstinence confirmed by biomarkers.

Why it matters

This study provides early feasibility and safety data suggesting psilocybin may improve smoking cessation outcomes beyond the typical success rates (<35%) of standard behavioral and pharmacological approaches.

Limits

The study is limited by a very small sample size (n=15), lack of a control or comparison group, an open-label design that introduces expectancy bias, and the inability to distinguish the pharmacological effects of psilocybin from the 15-week structured cessation protocol.

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