Efficacy of psychedelic treatments on depressive symptoms: A meta-analysis

A meta-analysis of eight studies found that psychedelic drugs produce a rapid and sustained reduction in depressive symptoms, with effects appearing as early as day one and lasting up to six months. No serious adverse effects were reported, though transient increases in heart rate and blood pressure occurred compared to placebo. The analysis included studies published through April 2019.

Study at a glance

Abstract

Background: Psychedelic drugs have shown an efficacy in some psychiatric disorders and have an original mechanism of action with a 5-HT 2A agonism. Aim: The aim of this meta-analysis was to assess by a quantitative analysis the putative efficacy of psychedelic drugs on depressive symptoms and to investigate the kinetic of this efficacy. Methods: We searched the MEDLINE and PsycINFO databases through April 2019, without limits on year of publication. Means and standard deviations were extracted to calculate standardized mean differences (SMD). Scores of depressive symptoms were compared with baseline scores at days 7, 14, and 21; weeks 4–5 and 6–8; and months 3 and 6. Results: Eight studies were included in this meta-analysis. A significant decrease of depressive symptoms was found from day 1 ( n = 5 studies; SMD = ‒1.4, 95% confidence interval (CI): ‒2.33 to ‒0.48, p = 0.003) to 6 months ( n = 4 studies; SMD = ‒1.07, 95% CI: ‒1.44 to ‒0.7, p < 0.001) after psychedelic sessions. No serious adverse effect was reported in all included studies. A transient increase of the heart rate, blood systolic, and diastolic pressure were found after psychedelics compared with placebo. Conclusion: This meta-analysis shows that psychedelic treatments were safe and could contribute to a rapid improvement of depressive symptoms.