OHSU-Led Study Finds Psilocybin Safe and Effective for Mood Disorders in 2,300 Real-World Users
Oregon Health & Science University researchers reported Wednesday that psilocybin was safe and effective for treating mood disorders in more than 2,300 users in state-regulated or community settings across Oregon. The real-world, longitudinal study tracked reductions in depression, anxiety, and PTSD symptoms over time, according to OHSU officials.
The study tracked more than 2,300 participants who used psilocybin services in Oregon’s state-regulated or community settings, making it one of the largest prospective naturalistic datasets on psilocybin to date, according to Oregon Health & Science University officials. Among those completing follow-up surveys, 50 to 60 percent experienced at least a 50% reduction in these symptoms, officials said. These findings align with prior clinical trials that have documented sustained reductions in depressive symptoms following single-dose psilocybin treatment for major depressive disorder.
Researchers reported that depression and anxiety scores, measured by the PHQ-9 and GAD-7 scales, dropped by about 50% within two weeks of dosing.
The OHSU-led research also found that participants reported decreased moderate-to-severe anxiety and reduced post-traumatic stress disorder symptoms at three months post-treatment. Improvements were not limited to symptom relief; participants indicated enhanced mental well-being and life satisfaction over the same period. According to the study, these outcomes suggest psilocybin’s potential benefits extend across a range of mood and trauma-related conditions. A large, independent naturalistic survey published in *Frontiers in Psychiatry* corroborated these results, showing enduring reductions in anxiety, depression, and alcohol misuse, alongside increased cognitive flexibility and spiritual well-being.
Safety data from the study were drawn from a multisite cohort of 346 adults receiving psilocybin services under OHSU supervision. Serious adverse reactions were uncommon, officials said, with only about 1% of participants experiencing serious negative mental health impacts. Among these, four first-time users required medical attention for acute behavioral reactions, illustrating that while rare, serious events can occur. Overall, longitudinal data from Oregon’s regulated psilocybin services indicated the treatments were generally safe and associated with improved mental health outcomes. These real-world safety findings are consistent with a broader systematic review and meta-analysis of psychedelics for mental disorders, which reported favorable safety profiles and few lasting negative effects.
Participant experiences were also documented. At one month post-treatment, 91.5% of participants reported benefiting from psilocybin, and 64.9% ranked the experience among the 10 most meaningful of their lives, according to OHSU records. These subjective reports of benefit and meaning persisted at three months, with continued improvements in mental well-being and life satisfaction. The broader naturalistic survey similarly found that most participants described ongoing mental health improvements and increased spiritual well-being, though a minority reported lingering negative effects such as mood fluctuations or residual depressive symptoms.
The OHSU psilocybin services program began in January 2023 following Oregon’s passage of pioneering psilocybin legislation. The program offers psilocybin-assisted therapy through licensed facilitators for patients experiencing depression and anxiety related to life-threatening illness. A February 12, 2026, OHSU news release detailed the research initiative, noting preliminary data from more than 300 clients and a goal to enroll at least 1,600 participants over five years. The study recruits through a statewide network of 31 licensed service centers and 350 facilitators, with participants followed for up to one year after dosing to assess both short- and longer-term mental health trajectories, officials said.
The OHSU findings are consistent with recent controlled clinical trials. A 2023 study published in *JAMA* found that single-dose psilocybin treatment for major depressive disorder produced clinically significant, sustained reductions in depressive symptoms and functional disability without serious adverse events. Open-label pilot studies on treatment-resistant depression reported large effect sizes and response or remission rates around 43%, providing a benchmark comparable to the improvements observed in the OHSU real-world cohort. Long-term follow-up from other psilocybin trials has shown that approximately two-thirds of participants remained in remission up to five years post-treatment.
In contrast, recent controlled research on psilocybin microdosing found no reliable cognitive or emotional benefits beyond placebo, according to study authors. This suggests that the high-dose, facilitated sessions used in the OHSU program are the primary drivers of observed mental health improvements. A 2024 systematic review and meta-analysis of psychedelics for mental disorders concluded that these substances show promising efficacy and a favorable safety profile, situating the OHSU real-world study within a growing body of converging evidence.
OHSU neuroscientist Adie Rae and colleagues have emphasized that the program aims to better understand psilocybin’s effects on mental health, substance use, and well-being in large, real-world samples, complementing controlled clinical trial data. The ongoing research will continue to monitor participants over time to provide further insights into the durability and scope of psilocybin’s therapeutic effects.
