Results from the first randomized, placebo-controlled trial of psilocybin for alcohol dependence showed that during the 8 months after first treatment dose, participants who received psilocybin had less than half as many heavy drinking days as their counterparts who received placebo.
In addition, 7 months after the last dose of medication, twice as many psilocybin-treated patients as placebo-treated patients were abstinent.
Dr. Michael Bogenschutz
The effects observed with psilocybin were “considerably larger” than those of currently approved treatments for AUD, senior investigator Michael Bogenschutz, MD, psychiatrist and director of the NYU Langone Center for Psychedelic Medicine, New York, said during an Aug. 24 press briefing.
If the findings hold up in future trials, psilocybin will be a “real breakthrough” in the treatment of the condition, Dr. Bogenschutz said.
The findings were published online in JAMA Psychiatry.
83% reduction in drinking days
The study included 93 adults (mean age, 46 years) with alcohol dependence who consumed an average of seven drinks on the days they drank and had had at least four heavy drinking days during the month prior to treatment.
Of the participants, 48 were randomly assigned to receive two doses of psilocybin, and 45 were assigned to receive an antihistamine (diphenhydramine) placebo. Study medication was administered during 2 day-long sessions at week 4 and week 8.
The participants also received 12 psychotherapy sessions over a 12-week period. All were assessed at intervals from the beginning of the study until 32 weeks after the first medication session.
The primary outcome was percentage of days in which the patient drank heavily during the 32-week period following first medication dose. Heavy drinking was defined as having five or more drinks in a day for a man and four or more drinks in a day for a woman.
The percentage of heavy drinking days during the 32-week period was 9.7% for the psilocybin group and 23.6% for the placebo group, for a mean difference of 13.9% (P = .01).
“Compared to their baseline before the study, after receiving medication, the psilocybin group decreased their heavy drinking days by 83%, while the placebo group reduced their heavy drinking by 51%,” Dr. Bogenschutz reported.
During the last month of follow-up, which was 7 months after the final dose of study medication, 48% of the psilocybin group were entirely abstinent vs. 24% of the placebo group.
“It is remarkable that the effects of psilocybin treatment persisted for 7 months after people received the last dose of medication. This suggests that psilocybin is treating the underlying disorder of alcohol addiction rather than merely treating symptoms,” Dr. Bogenschutz noted.
Total alcohol consumption and problems related to alcohol use were also significantly less in the psilocybin group.
‘Encouraged and hopeful’
Adverse events related to psilocybin were mostly mild, self-limiting, and consistent with other recent trials that evaluated the drug’s effects in various conditions.