Classic psychedelics and alcohol use disorders: A systematic review of human and animal studies

Classic psychedelics like LSD, psilocybin, ayahuasca, and mescaline act mainly on 5-HT2A receptors and are being studied as treatments for psychiatric disorders, including alcohol use problems. This systematic review analyzed 27 studies (20 human, 7 preclinical) published between 2000 and 2021. Human studies generally suggest that classic psychedelics could help reduce alcohol consumption, but many have methodological limitations such as small sample sizes or lack of control groups. Preclinical studies are scarce and show conflicting results. Psilocybin shows the most consistent data as a potential candidate for treating alcohol use disorders. More rigorous studies are needed to understand the underlying mechanisms.

Study at a glance

Abstract

Abstract Classic psychedelics refer to substances such as lysergic acid diethylamide (LSD), psilocybin, ayahuasca, and mescaline, which induce altered states of consciousness by acting mainly on 5‐HT 2A receptors. Recently, the interest of psychedelics as pharmacological treatment for psychiatric disorders has increased significantly, including their use on problematic use of alcohol. This systematic review is aimed to analyse the last two decades of studies examining the relationship between classic psychedelics and alcohol consumption. We searched PubMed and PsycInfo for human and preclinical studies published between January 2000 to December 2021. The search identified 639 publications. After selection, 27 studies were included. Human studies ( n = 20) generally show promising data and seem to indicate that classic psychedelics could help reduce alcohol consumption. Nevertheless, some of these studies present methodological concerns such as low number of participants, lack of control group or difficulty in determining the effect of classic psychedelics in isolation. On the other hand, preclinical studies ( n = 7) investigating the effect of these compounds on voluntary alcohol consumption are scarce and show some conflicting data. Among these compounds, psilocybin seems to show the most consistent data indicating that this compound could be a potential candidate to treat alcohol use disorders. In the absence of understanding the biological and/or psychological mechanisms, more studies including methodological quality parameters are needed to finally determine the effects of classic psychedelics on alcohol consumption.