Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: A randomized controlled trial

This double-blind placebo-controlled study (n=29) for those suffering from anxiety and depression, related to cancer, improved significantly (60-80% of participants) after a single dose of psilocybin (21mg/70kg) in combination with psychotherapy.


Background: Clinically significant anxiety and depression are common in patients with cancer, and are associated with poor psychiatric and medical outcomes. Historical and recent research suggests a role for psilocybin to treat cancer-related anxiety and depression.

Methods: In this double-blind, placebo-controlled, crossover trial, 29 patients with cancer-related anxiety and depression were randomly assigned and received treatment with single-dose psilocybin (0.3 mg/kg) or niacin, both in conjunction with psychotherapy. The primary outcomes were anxiety and depression assessed between groups prior to the crossover at 7 weeks.

Results: Prior to the crossover, psilocybin produced immediate, substantial, and sustained improvements in anxiety and depression and led to decreases in cancer-related demoralization and hopelessness, improved spiritual wellbeing, and increased quality of life. At the 6.5-month followup, psilocybin was associated with enduring anxiolytic and anti-depressant effects (approximately 60–80% of participants continued with clinically significant reductions in depression or anxiety), sustained benefits in existential distress and quality of life, as well as improved attitudes towards death. The psilocybin-induced mystical experience mediated the therapeutic effect of psilocybin on anxiety and depression.

Conclusions: In conjunction with psychotherapy, single moderate-dose psilocybin produced rapid, robust and enduring anxiolytic and anti-depressant effects in patients with cancer-related psychological distress.”

Authors: Stephen Ross, Anthony Bossis, Jeffrey Guss, Gabrielle Agin-Liebes, Tara Malone, Barry Cohen, Sarah E. Mennenga, Alexander Belser, Krystallia Kalliontzi, James Babb, Zhe Su, Patricia Corby & Brian L. Schmidt


This study is followed up by Long-term follow-up of psilocybin-assisted psychotherapy for psychiatric and existential distress in patients with life-threatening cancer (Agin-Liebis et al., 2020).

And by a qualitative analysis of Patient Experiences of Psilocybin-Assisted Psychotherapy: An Interpretative Phenomenological Analysis (Belser et al., 2017). And continued themes after the experience were also analysed (from the same dataset) in Swift and colleagues (2017). And another qualitative analysis of four patients by Malone and colleagues (2018).

The effects on suicidal ideation (SI) in this study group was done by Ross and colleagues (2021).

The article was published in the same edition of the Journal of Psychopharmacology as Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial (Griffiths & Johnson, 2016).

This study is included in a meta-analysis by Goldberg et al. (2020) – effect psilocybin on anxiety and depression, and another meta-analysis by Vargas et al. (2020) – effect psilocybin on anxiety and depression at end-of-life. And it was included in the meta-analytical review by GalvΓ£o-Coelho and colleagues (2021) that found psychedelics to improve mood (for those with mood disorders) both in the short and long-term (up to 60 days).

“Enduring clinically significant anxiety and/or depressive symptoms are common in patients with cancer, present in 30–40% of patients in hospital settings.”

Single moderate-dose psilocybin, in conjunction with psychotherapy, produced rapid, robust, and sustained clinical benefits in terms of reduction of anxiety and depression in patients with life-threatening cancer. This pharmacological finding is novel in psychiatry in terms of a single dose of a medication leading to immediate anti-depressant and anxiolytic effects with enduring (e.g. weeks to months) clinical benefits. Even though it is not possible to attribute causality of the experimental drug (in terms of sustained clinical benefit) after the crossover, the post-crossover data analyses of the two dosing sequences suggest that the clinical benefits, in terms of reduction of cancer-related anxiety and depression, of single-dose psilocybin (in conjunction with psychotherapy) may be sustained for longer than 7 weeks postdosing, and that they may endure for as long as 8 months post psilocybin dosing.”

As the follow-up (Agin-Liebes et al, 2020) shows, this is a very promising avenue of helping people with psychological distress related to cancer.

Since the early 1990s, approximately 2000 doses of psilocybin (ranging from low to high doses) have been safely administered to humans in the United States and Europe, in carefully controlled scientific settings, with no reports of any medical or psychiatric serious [adverse effects], including no reported cases of prolonged psychosis or HPPD. This finding is consistent with a US population (2001–2004 data from the National Survey on Drug Use and Health) based study that found no associations between lifetime use of any of the serotoninergic psychedelics (including psilocybin) and increased rates of mental illness.”

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