Real-world Study of Oregon Psilocybin Program Finds Mostly Positive Outcomes
A real-world study of Oregon's regulated psilocybin program found most participants reported benefits and few serious adverse reactions, though experts caution the findings may not generalize.
The study, published Wednesday in JAMA Network Open, analyzed survey responses from nearly 350 people who took psilocybin at state-licensed centers. Most described their experience as beneficial, and more than half ranked it among the most meaningful experiences of their lives. Only a small number experienced what the researchers classified as serious adverse reactions.
Dr. Todd Korthuis, who led the research at Oregon Health & Science University, said he had originally been skeptical about giving psilocybin outside a tightly controlled medical setting. "The data has swayed me," he told NPR. "These results are very reassuring."
Oregon voters approved the nonmedical model in 2020, allowing most adults 21 and older to take psilocybin at designated centers under a facilitator's supervision, without a prescription or medical referral. Colorado has also launched a psychedelic program, though adults there may use the drug outside supervised settings.
Balázs Szigeti, a clinical data scientist at the University of California, San Francisco, who was not involved in the study, told NPR that the number of adverse events was roughly what one would expect from other psychiatric interventions. "To see that the whole thing did not blow up in this regulated business environment is definitely good news for psilocybin," he said.
Participants gave varying reasons for using psilocybin, with curiosity, self-improvement, mental health and trauma listed most often. The average dose was about 30 milligrams, somewhat higher than doses typically used in clinical trials. More than half reported their mental health symptoms improved afterward, but Szigeti noted that finding is hard to interpret because the study was uncontrolled and participants had differing symptoms at the start. The improvement in mental well-being was similar to that seen in meditation studies, he added.
The safety issues that did arise were mostly behavioral rather than physical. One person was taken to a hospital after a violent reaction, and another went to an emergency room for anxiety. The four participants classified as having serious adverse reactions were all first-time psilocybin users. One week after their session, three participants reported new thoughts of dying or suicide; that figure doubled by the three-month mark.
The study group represents a small fraction of more than 20,000 people who have gone through Oregon's program since it began about three years ago. Participants were mostly white and college-educated, and about a third had household incomes over $200,000. Korthuis said those demographics closely mirror the broader population visiting the licensed centers, which are concentrated in the Portland area.
Albert Garcia-Romeu, a professor at Johns Hopkins School of Medicine who was not involved in the study, cautioned that the low number of adverse events could be an artifact of who chose to join the research or how incidents were reported. "This is a very small group of people and a rarified sample," he said. He added that he has personally spoken with numerous people in Oregon who struggled after their psilocybin experiences. "We really can't generalize based on this study that it's going to be this safe and look this way for everyone."