Research library / Clinical trial
Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial
Griffiths RR, Johnson MW, Carducci MA, et al. Journal of Psychopharmacology 2016;30(12):1181-1197
This trial gave 51 people with life-threatening cancer, who also had depression or anxiety, two psilocybin sessions five weeks apart: one at a high dose and one at a very low dose that acted like a placebo, in random order. Neither participants nor staff were told which came first. After the high dose, depression and anxiety fell sharply, while quality of life, sense of meaning and optimism rose and fear of death eased. Six months later, about four in five still had clinically meaningful improvements, and family and friends reported matching changes. The depth of the mystical-type experience helped explain who improved most. Because everyone eventually received the high dose, the long-term results lack a true control group, and strong drug effects make blinding imperfect.
What it found
- High-dose psilocybin produced large drops in clinician- and self-rated depression and anxiety, plus gains in quality of life, meaning and optimism and less death anxiety
- At 6 months about 80% still showed clinically significant reductions in depressed mood and anxiety
- Over 80% reported at least moderately increased well-being or life satisfaction attributed to the session
- The intensity of the mystical-type experience mediated the link between dose and outcome