Paul Stamets on health: what the evidence says · JRE #1385
“Fifteen patients, small clinical studies, statistically significant. Ten out of 15 people, after one or two heroic doses of psilocybin, 12 months later had not smoked a cigarette.”
What the evidence says
Stamets is describing a real 2014 Johns Hopkins open-label pilot study (Johnson, Garcia-Romeu, Cosimano & Griffiths) in which 15 nicotine-dependent smokers received two or three moderate-to-high doses of psilocybin alongside cognitive behavioral therapy; a 2017 long-term follow-up of that same cohort reported that 10 of 15 participants (67%) were biologically confirmed as smoking-abstinent at the 12-month mark, matching the numbers Stamets cites. However, the study had no control or placebo group, was small (N=15) and unblinded, and its authors explicitly stated the open-label design does not permit definitive conclusions about psilocybin's efficacy -- describing it as "statistically significant" understates how limited a 15-person, uncontrolled pilot is for proving a causal effect. A larger 2026 Johns Hopkins pilot randomized controlled trial (N=82) later found psilocybin plus CBT produced significantly higher 6-month abstinence (40.5%) than nicotine-patch plus CBT (10.0%), lending some controlled support to the original pilot's promise, though that trial remained unblinded and modest in size compared with standard smoking-cessation drug trials. Overall, the specific 10/15 and 12-month figures Stamets cites are accurate, but presenting the underlying pilot as definitive proof rather than preliminary, hypothesis-generating evidence overstates its strength.