In brief
- A phase 2 trial followed 28 patients with cancer and depression for two years after they were treated with a single 25 mg dose of psilocybin plus psychological support.
- About half of the participants maintained a clinically significant reduction in depression (50%) and anxiety (42.9%) at the two-year mark.
- These results are promising but preliminary: the study was open-label, lacked a placebo group, had a small sample size, and was conducted in a clinical setting with significant human support.
The idea that a single day of treatment could alleviate depression for two years sounds almost improbable. Yet, this is what the long-term follow-up of a phase 2 trial published in 2025 suggests: among patients with cancer and depression who received a single dose of psilocybin accompanied by psychological support, nearly half retained notable improvements two years later. The data is encouraging, though it should be read with the caution that its design necessitates.
The study
The work, authored by Manish Agrawal, Kim Roddy, Betsy Jenkins, Celia Leeks, and Ezekiel Emanuel, was published in the journal Cancer (from the American Cancer Society) in June 2025. It is a two-year follow-up of an open-label, non-randomized phase 2 trial conducted at a community oncology center in the United States. Thirty people with cancer and major depressive disorder participated; 28 completed the long-term evaluation. All received a single 25 mg dose of psilocybin in a supervised session, preceded and followed by preparation and integration sessions with psychological support, partly in a group format. Depression was measured using the Montgomery-Åsberg Depression Rating Scale (MADRS) and anxiety with the Hamilton Anxiety Rating Scale (HAM-A).
What was found
At the two-year mark, 15 of the 28 patients (53.6%) showed a significant reduction in depression, and 14 (50%) maintained that improvement in a sustained manner; the average drop in the MADRS was 15 points (p<0.001), a considerable magnitude on such a scale. Regarding anxiety, 13 people (46.4%) experienced a significant reduction, and 12 (42.9%) retained it after two years, with an average decrease of 13.9 points on the HAM-A (p<0.001). In other words, about half of those who received the treatment were still benefiting from it two years after that single session. For patients facing a serious illness—where depression and anxiety are frequent and difficult to treat—the persistence of the effect is perhaps the most striking aspect.
What it means (and what it doesn’t)
It is important to be honest in both directions. The results suggest that psilocybin, administered within a careful therapeutic framework, can produce lasting relief in a substantial portion of patients, something that conventional antidepressants rarely achieve with a single dose. However, the study design imposes clear limits. The study was open-label (everyone knew what they were receiving) and had no placebo group, so the effect of the molecule cannot be rigorously separated from the effect of expectations, intensive psychological support, or the passage of time itself. The sample is small—28 people—and was not randomized. Furthermore, the other half of the participants did not maintain a significant response: we are not talking about a universal cure, but rather a real benefit in approximately half of the cases.
It is also worth highlighting the context in which these figures were obtained. This was not solitary or recreational use, but a clinical intervention with a controlled dose, preparation and integration sessions, and healthcare personnel present throughout the entire experience. That therapeutic wrapper is not an accessory detail; it is likely part of what makes the effect safe and enduring. Extrapolating these results to unregulated use would be a misreading of the data.
At the regulatory level, psilocybin remains a controlled substance in most countries, available only within the framework of research or authorized therapeutic programs in specific jurisdictions. This is an objective fact of the current landscape, not a moral judgment: science advances while the law evolves at its own pace. Psychedelic research is experiencing a moment of expansion, but it still requires larger, randomized trials with appropriate comparators before we can firmly state for whom it works, under what conditions, and with what guarantees. The follow-up by Agrawal and his team adds a valuable—and hopeful—piece to that puzzle, without completing it.
Source
- Agrawal M, Roddy K, Jenkins B, Leeks C, Emanuel E. Long-term benefits of single-dose psilocybin in depressed patients with cancer. Cancer, 2025. DOI: 10.1002/cncr.35889
Educational content written from a harm reduction perspective and with respect for individual freedom. It is not a substitute for advice from a healthcare professional and is not intended to encourage or condemn any drug use.
