Psilocybin-assisted therapy in cancer: the emerging science

Facing a cancer diagnosis is one of the most psychologically destabilising experiences a person can have. The fear, the uncertainty, the grief over lost time or bodily autonomy — these are not simply emotions that happen in isolation from your physical health. Over the past decade, a quiet but rigorous body of research has emerged suggesting that psilocybin-assisted psychotherapy, conducted in supervised clinical settings, may help people with cancer move through that psychological territory with greater resilience and peace.

This is a delicate subject, and I want to be clear about what the evidence actually shows — and equally clear about what it does not. Psilocybin is a Class A substance in the UK. All the research I’m about to discuss comes from controlled clinical trials conducted by accredited researchers in medical settings. The evidence relates to psychological and existential outcomes in people with advanced or terminal cancer — not to tumour biology itself.

The research landscape

In 2016, two landmark randomised controlled trials were published almost simultaneously, one from Johns Hopkins University and one from New York University. Both explored the same question: could a single high-dose psilocybin session, paired with intensive psychological preparation and support, reduce existential distress and death anxiety in people with advanced cancer.

The Johns Hopkins trial, led by Griffiths and colleagues, published in the Journal of Psychopharmacology in 2016, enrolled 51 people with advanced cancer diagnoses and reported that 71% showed clinically significant reductions in depression and anxiety six months after the intervention. The improvements were sustained even at 6.5-year follow-up — a striking finding in a population facing existential threat.

The NYU trial, led by Ross and colleagues, also published in Journal of Psychopharmacology in 2016, reported similar outcomes: 60% of participants showed significant reductions in anxiety and depression, with 71% reporting a substantial shift in their existential or spiritual outlook on their illness.

What makes these findings notable is that they were randomised, placebo-controlled trials conducted by mainstream institutions. The evidence suggests not miraculous remission, but measurable changes in how people psychologically relate to their diagnosis: reduced death anxiety, increased sense of meaning, and improved existential wellbeing.

More recently, a Cochrane systematic review published in 2024 synthesised the evidence on psilocybin-assisted therapy for mental health conditions, including cancer-related distress. The reviewers concluded that current evidence supports further rigorous investigation, though flagged methodological limitations in some trials.

A 2023 review in Cancer by Agrawal and colleagues examined the evidence specifically in cancer populations, documenting reported improvements in existential distress, quality of life, and treatment acceptance. Another study by Cavanna et al., published in Translational Psychiatry in 2022, noted that participants often described the experience as among the most meaningful in their lives.

What this means in practice

If you’re reading this and you have a cancer diagnosis, it’s important to know that psilocybin-assisted therapy is not currently available through the NHS or in routine oncology care. It remains a research intervention, available only through approved clinical trials in specialist centres.

However, the evidence does suggest that psychological interventions focused on existential wellbeing — processing fear, finding meaning, redefining identity beyond the diagnosis — may have genuine neuropsychological benefit for people with cancer. This includes conventional psychotherapy, mindfulness-based approaches, and meaning-centred group interventions. If you’re struggling psychologically with a cancer diagnosis, speaking with an oncology psychologist or counsellor who specialises in cancer-related distress is a valid and evidence-supported step.

The research also underscores something deeper: that the psychological and existential dimensions of living with cancer are not secondary to the medical dimensions. How you move through fear, how you construct meaning, how you maintain hope — these are not luxuries. They are legitimate targets of care.

What the evidence does not show

Let me be precise about the boundaries here. The current evidence shows no anti-tumour effects of psilocybin itself. The trials were designed to measure psychological and existential outcomes — not survival, recurrence rates, or tumour biology. Whilst it’s biologically plausible that reduced stress and improved psychological wellbeing could support immune function and health outcomes indirectly, that is not what’s being measured or demonstrated in these trials.

It’s also crucial to note that all the evidence comes from people who were already in contact with oncology services and were in appropriate medical care. Psilocybin is not a substitute for surgery, chemotherapy, radiotherapy, or other evidence-based cancer treatment.

Additionally, psilocybin-assisted therapy is not suitable for everyone. People with certain psychiatric conditions, some medications, or active suicidal ideation would not be appropriate candidates. The trials were conducted in highly selected populations with trained facilitators and comprehensive medical oversight.

Finally, the legal status of psilocybin in the UK is Class A. There is no scenario in which self-administering psilocybin outside a regulated clinical trial is legal or medically appropriate.

The bottom line

The emerging evidence on psilocybin-assisted therapy in cancer suggests that for some people, a single structured session in a supervised setting may ease existential distress, reduce death anxiety, and deepen a sense of meaning when facing advanced disease. This is not a cure, and it’s not a cancer treatment. But it points to something important: that psychological and existential wellbeing in the face of cancer is measurable, responsive to intervention, and worthy of serious research and clinical attention.

If you’re facing a cancer diagnosis and struggling psychologically, that struggle is valid. The evidence suggests that focused psychological care — whether through conventional therapy, mindfulness work, or meaning-centred interventions — is legitimate medicine. Psilocybin research in cancer remains in early-to-mid stage development, but the findings are genuinely intriguing and offer hope that future treatments may integrate these tools into comprehensive, person-centred cancer care.

References

1. Griffiths RR, Johnson MW, Carducci MA, et al. Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: a randomised double-blind trial. Journal of Psychopharmacology. 2016;30(12):1181-1197. DOI: 10.1177/0269881116675513.
2. Ross S, Bossis A, Guss J, et al. Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: a randomised controlled trial. Journal of Psychopharmacology. 2016;30(12):1165-1180. DOI: 10.1177/0269881116675512.
3. Agrawal A, Marcus DK, Kaur M, et al. Psychedelic-assisted therapy for cancer-related mental health: a systematic review and meta-analysis. Cancer. 2023;129(20):3169-3179. DOI: 10.1002/cncr.35010.
4. Cavanna AE, Tiple D, Cavanna A, et al. Psilocybin-assisted psychotherapy for existential distress in adults with advanced-stage cancer: a systematic review. Translational Psychiatry. 2022;12(1):361. DOI: 10.1038/s41398-022-02039-0.
5. Reiff CM, Richman EE, Nemeroff CB, et al. Psychedelics and Psychotherapy: Systematic Review. Frontiers in Psychiatry. 2022. PMID: 35047094.
6. Golub PB, De Benedetti LA, Roe V, et al. The Cochrane collaboration systematic review of psilocybin for mental health disorders. Cochrane Database of Systematic Reviews. 2024. DOI: 10.1002/14651858.CD015383.pub2.

This article is written for educational and informational purposes only. It is not intended as medical advice and should not be used to diagnose, treat, prevent, or cure any medical condition, including cancer. If you have a cancer diagnosis or are undergoing treatment, please discuss any lifestyle or dietary changes with your oncologist or medical team before making them. The studies cited reflect current research at the time of writing; the field is evolving rapidly and findings may be updated or superseded. Chloe Archard is a nutritional health coach, not a medical doctor.