TABLE 1.

Clinical trials evaluating the efficacy of psilocybin in substance-use disorders.

Article and country	Study design	Participants	Substance use disorder	Intervention	Control group	Follow-up	Primary outcome
Bogenschutz et al. (25), United States of America	Non-randomized	N = 10 (4 women and 6 men), mean age 40.1 years (SD = 10.3), mean duration alcohol use disorder 15.1 years (SD = 11.5), recruited using advertisements in local media	Alcohol	Psilocybin 21 mg/70 kg at week 4 and 28 mg/70 kg at week 8 + a psychosocial intervention (12 sessions)	No	36 weeks	Percentage heavy drinking days baseline vs. weeks 5–12
Bogenschutz et al. (26), United States of America	Randomized	N = 95 (42 women and 53 men), mean age 45.8 years (SD = 11.6), mean duration alcohol use disorder 14.2 years (SD = 9.7), recruited using advertisements in local media	Alcohol	Psilocybin 25 mg/70 kg- at week 4 and 25–40 mg/70 kg at week 8 + a psychosocial intervention (12 sessions)	Diphenhydramine 50 mg at week 4 and 50–100 mg at week 8 + a psychosocial intervention (12 sessions)	36 weeks	Percentage heavy drinking days over a 32-week period
Rydzyński et al. (27, 28), Poland	Non-randomized	N = 31 (31 men), mean age 37.9 years (SD unknown), mean duration of alcohol use disorder unknown, recruitment method unknown	Alcohol	Alternating psilocybin 6–30 mg (mean 15 sessions) and LSD 100–800 mcg (mean 12 sessions) in 5–7 day intervals + psychotherapy (number of sessions unknown)	No	Mean 6 years	Percentage abstinent from alcohol
Johnson et al. (29, 30), United States of America	Non-randomized	N = 15 (5 women and 10 men), mean age 51.0 years (SD = 10.5), mean duration of smoking 31.0 years (SD = 9.9), recruited using advertisements	Tobacco	Psilocybin 20 mg/70 kg at week 5; 30 mg/70 kg at week 7 and 9 + cognitive behavioral therapy (4 sessions)	No	52 weeks	Seven-day point prevalence abstinence at 26 and 52 weeks

SD, standard deviation.