Psychedelic drugs in the treatment of anxiety, depression and addiction

Abstract

BACKGROUND There is growing interest in the use of psychedelic drugs for the treatment of mental disorders. The drugs are considered safe when administered within a clinical framework. Older studies performed prior to 1970 had methodological shortcomings, but studies in recent years have shown promising results regarding the use of psychedelic drugs in unipolar depression, depression in life-threatening illness, anxiety and addiction. The aim of this literature review is to provide an overview of recent results and the limitations of these studies. METHOD We searched the PubMed database for clinical studies from the period 1990–2017 with the keywords anxiety, depression, addiction and psychedelic drugs. The quality of the studies was then assessed on the basis of their methods and statistical power. RESULTS The search yielded 424 articles, of which nine were included (four on anxiety and depression in life-threatening illness, two on depression, two on addiction disorders and one on obsessive-compulsive disorder). Two double-blind, randomised, controlled phase II trials with moderate sample sizes reported immediate, marked and sustained efficacy of a single dose of psilocybin against anxiety and depression in life-threatening illness. The results of the other studies were less clear. There were no serious adverse effects or reports of addiction. INTERPRETATION Psychedelic drugs have shown promising results in the treatment of several mental disorders, but the studies are small and have methodological shortcomings. There is a need for systematic clinical trials to obtain robust evidence of efficacy and to establish routines for the monitoring of potential adverse effects.