The First Federal Study of Legal Psilocybin Services Is Now Underway in Oregon

Oregon legalized supervised psilocybin services for adults in 2020. The first licensed service centers opened in 2023. Since then, an estimated 15,000 Oregonians have participated in sessions involving the psychoactive compound - making Oregon's program by far the largest real-world database of legal psilocybin use in the world. Almost none of that experience has been systematically studied.

Oregon Health and Science University has received a five-year, $3.3 million award from the National Institute on Drug Abuse - part of NIH - to begin changing that. The research will track participants in Oregon's state-regulated psilocybin program, with a particular focus on substance use outcomes, and will represent the first federally funded study of legal psychedelic services delivered in real-world community settings.

Why the Clinical Trial Record Is Not Enough

The history of modern psychedelic clinical research has produced data on only about 3,000 trial participants since the 1950s. Those trials are tightly controlled, highly selective, and conducted in clinical rather than community settings. They tell researchers what psilocybin can do under ideal, supervised conditions with carefully screened participants. They say much less about what it actually does when accessed through licensed providers by ordinary people who may have complex health histories, current substance use, or no diagnosable psychiatric condition.

Oregon's program has no diagnostic requirement. It is open to anyone 21 and older, who works with licensed facilitators in approved service centers. This produces a fundamentally different population - broader, more representative of who would actually use these services if they became widely available elsewhere.

"Only about 3,000 people have participated in all psychedelic clinical trials combined since the 1950s," said Todd Korthuis, co-principal investigator and professor of medicine at OHSU. "This project is an opportunity to learn from tens of thousands of people who will access psilocybin services in Oregon."

What the Study Will Measure

The OHSU team, operating through the Oregon Psychedelic Evaluation Nexis (OPEN), will specifically examine psilocybin's effects on people with substance use disorders. This is a strategic choice: early clinical work focused primarily on depression, anxiety, and PTSD, where the evidence base is more developed. The literature on psilocybin's effects on tobacco cessation and alcohol use disorder is emerging but thin, and preliminary data from Oregon indicate that people are already accessing psilocybin services specifically to help manage substance use.

The study design will recruit participants who want to reduce substance use - both those accessing psilocybin services and those who are not. Comparing those two groups allows researchers to estimate psilocybin's effect relative to the baseline of wanting to change. Participants complete a baseline survey followed by six additional surveys and interviews over twelve months after their initial session.

Researchers have already enrolled more than 300 initial participants. The goal is to reach at least 1,600 over five years. That sample size allows subgroup analyses identifying which substances and which types of people appear to respond to psilocybin's effects - and which do not.

Federal Research Under State-Federal Tension

Psilocybin remains a Schedule 1 controlled substance under federal law, alongside cannabis and heroin, despite being legal for supervised use in Oregon and - subsequently - Colorado. This legal status has historically made federal research funding for psilocybin extremely difficult to obtain. The NIH award is a meaningful signal that federal science agencies can study these compounds in the settings where they are actually being used, even while the federal-state legal tension remains unresolved.

Co-principal investigator Adie Rae, a scientist at the Legacy Research Institute in Portland and co-director of OPEN, framed the stakes in terms of policy needs: "There is an urgent need to assess the safety of these programs and their impact on substance use before more voters and policymakers are asked to consider their merits and drawbacks. Right now, we do not have much to tell clients about safety, likelihood of symptom improvement, or side effects."

Limitations to Acknowledge

The study is observational rather than randomized. People who choose to access psilocybin services are self-selected and differ from those who do not in ways that are difficult to fully account for. Self-reported survey data on substance use is subject to social desirability bias - people may underreport ongoing use. The twelve-month follow-up window may miss longer-term effects in either direction.

These constraints mean the study will produce associations and estimates of effect, not definitive proof of causation. But population-level observational data from a legal system, collected rigorously and at scale, fills a category of knowledge that clinical trials cannot provide.

Ryan Cook, assistant professor of medicine at OHSU and co-principal investigator, described the study's core value: "People have strong viewpoints when it comes to psychedelics. I am excited to do this study because we are going to rigorously collect and evaluate the data in a way that has never been done before."

The research is supported by NIH/NIDA award R01DA060253.