Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial

This study investigated the effects of a high dose of psilocybin on depression and anxiety in patients with life-threatening cancer. It found significant improvements, even without psychotherapy (as many other studies do provide).


“Cancer patients often develop chronic, clinically significant symptoms of depression and anxiety. Previous studies suggest that psilocybin may decrease depression and anxiety in cancer patients. The effects of psilocybin were studied in 51 cancer patients with life-threatening diagnoses and symptoms of depression and/or anxiety. This randomized, double-blind, cross-over trial investigated the effects of a very low (placebo-like) dose (1 or 3 mg/70 kg) vs. a high dose (22 or 30 mg/70 kg) of psilocybin administered in counterbalanced sequence with 5 weeks between sessions and a 6-month follow-up. Instructions to participants and staff minimized expectancy effects. Participants, staff, and community observers rated participant moods, attitudes, and behaviors throughout the study. High-dose psilocybin produced large decreases in clinician- and self-rated measures of depressed mood and anxiety, along with increases in quality of life, life meaning, and optimism, and decreases in death anxiety. At 6-month follow-up, these changes were sustained, with about 80% of participants continuing to show clinically significant decreases in depressed mood and anxiety. Participants attributed improvements in attitudes about life/self, mood, relationships, and spirituality to the high-dose experience, with >80% endorsing moderately or greater increased well-being/life satisfaction. Community observer ratings showed corresponding changes. Mystical-type psilocybin experience on session day mediated the effect of psilocybin dose on therapeutic outcomes.”

Authors: Roland R. Griffiths & Matthew W. Johnson


This paper is included in our ‘Top 10 Articles Introducing Psychedelic-Assisted Therapy

The article was published in the same edition of the Journal of Psychopharmacology as Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: A randomized controlled trial

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.

“Briefly, preparation meetings before the first session, which included discussion of meaningful aspects of the participant’s life, served to establish rapport and prepare the participant for the psilocybin sessions. During sessions, monitors were nondirective and supportive, and they encouraged participants to “trust, let go and be open” to the experience. Meetings after sessions generally focused on novel thoughts and feelings that arose during sessions.”

Although the level of support was much less directive, the effects (>80% endorsing moderately or greater increased well-being/life satisfaction.) indicate that possibly psychotherapy may not be a necessary requirement for treating patients (of this rather extreme population) with such level of attention towards the talk-therapy part of the treatment.

It is interesting to note that the adverse effects (vomiting, and ‘personal reasons’) were too high at 30mg/70kg, so the dose was reduced to 22mg/70kg for all participants after the first three participants. The same applied to the low (placebo) dose that was lowered from 3 to 1mg/70kg because there were already significant effects at that dose.

“When administered under psychologically supportive, double-blind conditions, a single dose of psilocybin produced substantial and enduring decreases in depressed mood and anxiety along with increases in quality of life and decreases in death anxiety in patients with a life-threatening cancer diagnosis. Ratings by patients themselves, clinicians, and community observers suggested these effects endured at least 6 months. The overall rate of clinical response at 6 months on clinician-rated depression and anxiety was 78% and 83%, respectively. A multisite study in a larger and more diverse patient population should be conducted to establish the generality and safety of psilocybin treatment of psychological distress associated with life-threatening cancer.”

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