Classic psychedelics and personality: An updated systematic review.
Anna Beatriz Vicentini, Caio César De Paula, José Augusto Silva Reis, José Carlos Bouso, Jaime E C Hallak, Rafael G Dos Santos
Journal of psychopharmacology (Oxford, England) May 31, 2026 Peer reviewed DOI: 10.1177/02698811261449386 via PubMed
Summary
Classic psychedelics, particularly psilocybin and ayahuasca, are linked to lasting personality changes, notably increases in Openness and reductions in Neuroticism. A systematic review of 48 studies found that while changes in traits like Extraversion, Agreeableness, and Conscientiousness were variable, microdosing was associated with modest reductions in Neuroticism and higher Absorption. The findings suggest a potential for psychedelics to influence personality traits over time.
Study at a glance
| Design | systematic review |
|---|---|
| Sample size | 48 |
| Population | studies involving the consumption of classic psychedelics and personality assessment |
| Key finding | Classic psychedelics promote lasting increases in Openness and reductions in Neuroticism. |
Abstract
The impact of classic psychedelics (5-HT2A receptor agonists) on personality traits has been studied for decades, and it has been hypothesized that the mechanisms underlying these changes are linked to agonism at cortical serotonergic 5-HT2A receptors. However, research results are contradictory. Therefore, the present paper aims to systematically evaluate the effects of psychedelics on personality, updating (2016-2024) a previous systematic review by Bouso and collaborators (2018). The International Prospective Register of Systematic Reviews ID for this study is CRD42024582704. Systematic review using four databases (PubMed, LILACS, PsycINFO, and SciELO) including randomized controlled trials, open-label, and observational studies. Interventions included the consumption of any classic psychedelic (lysergic acid diethylamide, psilocybin, ayahuasca/dimethyltryptamine, mescaline), and the studies were required to use some instrument for personality assessment. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to conduct the data collection. Out of 6043 references screened, 48 studies were included: 14 experimental and 34 observational. The most consistent findings were increases in Openness and reductions in Neuroticism, especially with psilocybin and ayahuasca. Changes in other traits, such as Extraversion, Agreeableness, and Conscientiousness, were more variable. Microdosing was associated with modest reductions in Neuroticism and higher Absorption. Most studies used instruments based on the Five-Factor Model, reflecting its growing dominance. Classic psychedelics seem to promote lasting personality changes, most consistently increasing Openness and reducing Neuroticism. Future research would benefit from combining experimental and naturalistic designs, using longer follow-up periods and more diverse personality models to better understand the interplay between psychedelics and personality, thus providing a more accurate guide for clinical use.