Pooled review: psilocybin and psychological distress in people with cancer

The question

Can psilocybin ease the depression, anxiety and distress that often come with a cancer diagnosis? Researchers pooled the existing trials to find out.

What they did

The team searched six research databases (Scopus, PsycINFO, PubMed, Cochrane, CINAHL Complete and Web of Science) for studies published up to November 2024. They included both randomized controlled trials and studies without a control group that gave psilocybin to people with cancer. Outcomes covered anxiety, depression, quality of life and spiritual well-being, measured at short-term (2 to 5 weeks) and long-term (6 months) follow-up. Study quality was judged with Cochrane tools and results were combined statistically.

What they found

In the randomized trials, depression scores dropped substantially on two common questionnaires: the Beck Depression Inventory (standardized mean difference -2.87, 95% confidence interval -3.99 to -1.76, p < 0.001) and the depression part of the Hospital Anxiety and Depression Scale (-2.97, 95% CI -3.60 to -2.33, p < 0.001). Anxiety results were mixed: the anxiety part of the same scale did not reach statistical significance (-3.63, p = 0.11), and another anxiety measure, the State-Trait Anxiety Inventory, gave inconsistent results. At 2 to 5 weeks there were significant improvements in depression (-1.17 and -1.58) and anxiety (-1.99), all p < 0.001, and at 6 months depression benefits persisted (-2.60, p = 0.04 and -3.56, p = 0.01). Quality of life and spiritual well-being scores also improved significantly, though the quality-of-life data came from studies without a comparison group.

The fine print

The abstract does not report how many studies or people were included, which makes the pooled effects hard to interpret. The authors themselves flag the small number of studies, large differences between them, difficulty keeping participants and staff unaware of who got psilocybin, and the fact that psilocybin was usually paired with psychotherapy, so the drug’s own contribution is unclear. Some results, including quality of life, come from single-arm studies with no control group. This summary is based on the abstract alone.

What it means

Pooled evidence points to meaningful short- and longer-term reductions in depression scores among people with cancer who received psilocybin alongside psychological support, while effects on anxiety are less consistent. The authors describe the findings as preliminary and call for larger, better-blinded trials.

Evidence grade: Moderate. A meta-analysis that pools both randomized and non-randomized trials, with few studies, high variability between them and blinding problems.

This summary is based on the study’s published abstract.