Years after one psilocybin session: a long-term look at people with cancer
Photo: Eduardo Barrios on Unsplash
The question
In 2016, a trial at NYU found that a single psilocybin session (psilocybin is the active compound in "magic mushrooms"), given with psychotherapy, eased anxiety and depression in people with life-threatening cancer for at least 6.5 months. That left an obvious next question. Do those changes last for years, or do they fade? This follow-up study went back to the same participants to find out.
Who took part and what happened
The original trial had 29 participants. By the time of this follow-up, 13 of them had died. The team contacted the 16 who were still alive, and 15 agreed to take part.
- This was a long-term follow-up (checking in again with people from an earlier study). No one received psilocybin again as part of this study.
- Participants filled out the same kinds of questionnaires as before: on anxiety, depression, hopelessness, demoralization (feeling defeated or without purpose), fear of death, quality of life and spiritual well-being.
- They were assessed twice: on average 3.2 years and 4.5 years after their psilocybin session. One more participant died between the two check-ins, so 14 people completed the second one.
- They were also asked how they viewed the experience now, and whether it changed their lives.
What they found
- Improvements held. Lower levels of anxiety, depression, hopelessness, demoralization and death anxiety were still present at both follow-ups, compared with before the original trial. The changes were large in statistical terms.
- At about 4.5 years, roughly 60–80% of participants still met the study's criteria for a clinically meaningful drop in depression or anxiety.
- Meaning. Between 71% and 100% of participants (depending on the question) said they credited positive life changes to the experience, and rated it among the most personally meaningful and spiritually significant experiences of their lives.
- No lasting harm reported. No participants reported lasting negative effects from their psilocybin session.
- Some had other care in the meantime. Since the original trial, 5 of 13 reported some psychotherapy, and 3 of 13 had taken psychiatric medication, though none of it for cancer-related distress specifically.
What this study does not tell us
- No comparison group. In the original trial everyone eventually received psilocybin. So there is no group of similar people who did not, to compare with years later. Life events, time and other help could all play a role.
- Very small and selective. Only 15 people, and only those who survived and agreed to take part. People who felt better may have been more willing to answer.
- Not a diverse group. About 94% were non-Hispanic white, and most were well educated with higher incomes.
- Drug and therapy came together. The effect of psilocybin can't be separated from the psychotherapy around it.
- Self-report. The results rely on questionnaires people filled in about themselves.
- A controlled clinical setting. The original sessions involved careful medical screening and trained professional support. The results may not apply to other people or settings.
Why it matters
Few studies follow people this long after a single psilocybin session. This one suggests that, for many in this small group, the changes reported after the original trial were still there years later. That is worth taking seriously. But the authors are clear that the design limits firm conclusions, and they call for larger, placebo-controlled trials without a crossover. Think of this as an encouraging signal, not a final answer.
This is a summary of published research for general information. It is not medical advice. The study took place in a clinical research setting with medical screening and professional support.
Source: Agin-Liebes GI, Malone T, Yalch MM, Mennenga SE, Ponté KL, Guss J, Bossis AP, Grigsby J, Fischer S, Ross S (2020). Long-term follow-up of psilocybin-assisted psychotherapy for psychiatric and existential distress in patients with life-threatening cancer. Journal of Psychopharmacology, 34(2), 155–166. doi:10.1177/0269881119897615 · PubMed
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