Oregon Has Run the Largest Real-World Psilocybin Experiment on Earth. The First Full Results Are In.

Clinical trials for psilocybin are tightly screened — specific diagnoses, specific dosing, a research team watching every minute. Oregon’s licensed psilocybin service centers, operating under the ballot measure voters passed in 2020, are the opposite: any adult 21 or older can walk in, no diagnosis required, a trained facilitator instead of a psychiatrist in the room. More than 20,000 people have done it since licensure began in 2023. Nobody had rigorously tracked what actually happens to them outside a lab — until a study out of Oregon Health & Science University, published this week, did exactly that.

The best evidence yet that legal, unscreened psilocybin access doesn’t produce a wave of harm is now sitting in a peer-reviewed dataset, not a press release.

Researchers led by Dr. Todd Korthuis followed 346 people across 24 of Oregon’s 26 licensed centers from November 2024 through this June, checking in at one week, one month, and three months — a 90 percent retention rate that’s unusually high for this kind of follow-up study. At one month, 91.5 percent said they’d benefited from the session, and nearly two-thirds ranked it among the ten most meaningful experiences of their life. By three months, participants showed measurable drops in depression, anxiety, and PTSD symptoms.

The safety numbers are the part worth sitting with if you’re skeptical of loosely regulated psychedelic access: only seven of the 346 participants reported the experience as harmful, and four first-time users needed medical attention for an adverse behavioral reaction. No serious physical health events. That’s a strikingly low harm rate for a population that, unlike a clinical trial’s screened cohort, wasn’t filtered for psychiatric stability going in.

This doesn’t settle the FDA question — a real-world observational study isn’t a randomized controlled trial, and Compass Pathways’ actual Phase 3 program for treatment-resistant depression is still the thing that will determine whether psilocybin gets approved as medicine. But it does something a trial can’t: it shows what happens when the general public, not a research cohort, gets access under real supervision. So far, in Oregon, that answer looks better than the skeptics expected.