The psychopharmacology of hallucinogens

Introduction

The paper reviews the history, pharmacology, epidemiology, adverse effects and therapeutic claims surrounding classical hallucinogens such as LSD, mescaline, psilocybin and related agents. The authors place these drugs in a long anthropological and scientific context—from traditional botanical use and ergotism epidemics to 20th-century psychopharmacology—and highlight divergent societal and scientific attitudes that have oscillated between optimism about therapeutic potential and concern about harms. They emphasise continuing controversies regarding whether hallucinogens can produce prolonged psychoses, hallucinogen persisting perception disorder (HPPD), and whether they have robust, demonstrable clinical utility in psychiatry. D. and colleagues set out to synthesise available human data on hallucinogens across several domains: prevalence and patterns of use, acute physiological and psychological effects, longer-term psychiatric sequelae (including persistent perceptual disorders and psychotic reactions), and the evidence base for therapeutic applications (notably in alcoholism and psychotherapy). The review also examines methodological issues in the literature and proposes directions for future basic and clinical research. The paper includes a small meta-analytic test addressing whether psychiatric patients are at higher risk of prolonged psychoses after LSD exposure.