Research library / Clinical trial

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

Ross S, Bossis A, Guss J, et al. Journal of Psychopharmacology 2016;30(12):1165-1180

This trial tested a single dose of psilocybin in 29 people with cancer who had significant anxiety and depression. Participants were randomly given either psilocybin or niacin (a vitamin that causes flushing, used as an active placebo), both alongside psychotherapy, and later switched to the other. In the comparison period before the switch, psilocybin led to fast, lasting drops in anxiety and depression, and to less hopelessness and better quality of life. About six and a half months later, roughly 60 to 80 percent still had meaningful reductions in symptoms. How strong a 'mystical' experience people had helped explain how much they improved. The trial is small, and after the crossover every participant had taken psilocybin, so the long-term figures cannot be compared with an untreated group.