Psilocybin Efficacy and Mechanisms of Action in Major Depressive Disorder: a Review

Purpose of the Review We aim to provide an overview of the current state of knowledge about the efficacy of psilocybin in the treatment of depression, as well as its mechanisms of action. Recent Findings Psilocybin has a large, rapid, and persistent clinical effect in the treatment of resistant or end-of-life depression. Tolerance is good, with mild side effects limited to a few hours after dosing. The studies conducted to date have had small sample sizes. One clinical trial has been conducted against a reference treatment (escitalopram) without showing a significant superiority of psilocybin in the main outcome. The neurobiological mechanisms, mostly unknown, differ from those of SSRI antidepressants. Summary Psilocybin represents a promising alternative in the treatment of depression. Further research with larger sample sizes, particularly against reference treatments, is needed to better understand the neurobiological factors of its effects and to investigate its potential for use in everyday practice.