Adverse Events in Studies of Classic Psychedelics

A clear and comprehensive understanding of risks associated with psychedelic-assisted therapy is necessary as investigators extend its application to new populations and indications.

To assess adverse events (AEs) associated with classic psychedelics, particularly serious AEs (SAEs) and nonserious AEs (NSAEs) requiring medical or psychiatric evaluation. Data Sources: The search for potentially eligible studies was conducted in the Scopus, MEDLINE, PsycINFO, and Web of Science databases from inception through February 8, 2024. Study Selection: Two independent reviewers screened articles of classic psychedelics (lysergic acid diethylamide [LSD], psilocybin, dimethyltryptamine [DMT], and 5-methoxy-N,N-dimethyltryptamine [5-MeO-DMT]) involving administration in clinical or research contexts. Data Extraction and Synthesis: AE data were extracted and synthesized by 2 reviewers and were used for random-effects meta-analysis of AE frequency and heterogeneity. Risk of bias assessment focused on AE ascertainment (eg, systematic assessment and quality of follow-up). Main Outcomes and Measures: A hybrid approach was used for capture of all reported AEs following high-dose classic psychedelic exposure and confirmatory capture of AEs of special interest, including suicidality, psychotic disorder, manic symptoms, cardiovascular events, and hallucinogen persisting perception disorder. AEs were stratified by timescale and study population type. Forest plots of common AEs were generated, and the proportions of participants affected by SAEs or NSAEs requiring medical intervention were summarized descriptively.