Long-term effects of psychedelic drugs: A systematic review
Jacob S. Aday, Cayla M. Mitzkovitz, Emily K. Bloesch, Christopher C. Davoli, Alan K. Davis
Neuroscience & Biobehavioral Reviews March 16, 2020 DOI: 10.1016/j.neubiorev.2020.03.017 via OpenAlex
Summary
AI-generated from the abstractA systematic review of 34 experimental studies on classic psychedelics with follow-up periods of at least two weeks found lasting changes in personality, attitudes, depression, spirituality, anxiety, wellbeing, substance misuse, meditative practices, and mindfulness. Psilocybin was the most commonly administered drug. Mystical experiences, connectedness, emotional breakthrough, and increased neural entropy were linked to these long-term psychological changes. With proper screening, preparation, supervision, and integration, participants reported few aversive side effects. The review calls for larger, more diverse samples, longer longitudinal designs, stronger control conditions, and standardized dosages in future research.
Study at a glance
| Characteristics | Systematic review Longitudinal Peer reviewed |
|---|---|
| Sample size | 34 |
| Population | Human subjects in experimental studies of classic psychedelics |
| Interventions | psilocybin classic psychedelics |
| Duration | Follow-up latencies of at least two weeks |
| Keywords | Term time Psychology Hallucinogen Neuroscience Medicine |
| Citations | 260 |
| Key finding | Classic psychedelics produce enduring changes in multiple psychological domains, with mystical experiences and neural entropy linked to these long-term effects. |
Abstract
Research into the basic effects and therapeutic applications of psychedelic drugs has grown considerably in recent years. Yet, pressing questions remain regarding the substances' lasting effects. Although individual studies have begun monitoring sustained changes, no study to-date has synthesized this information. Therefore, this systematic review aims to fill this important gap in the literature by synthesizing results from 34 contemporary experimental studies which included classic psychedelics, human subjects, and follow-up latencies of at least two weeks. The bulk of this work was published in the last five years, with psilocybin being the most frequently administered drug. Enduring changes in personality/attitudes, depression, spirituality, anxiety, wellbeing, substance misuse, meditative practices, and mindfulness were documented. Mystical experiences, connectedness, emotional breakthrough, and increased neural entropy were related to these long-term changes in psychological functioning. Finally, with proper screening, preparation, supervision, and integration, limited aversive side effects were noted by study participants. Future researchers should focus on including larger and more diverse samples, lengthier longitudinal designs, stronger control conditions, and standardized dosages.