Classic psychedelics and personality: An updated systematic review

This latest review examined evidence from 48 studies (14 experimental and 34 observational) published between 2016 and 2024 on whether classic psychedelics produce lasting changes in personality.

This new review examined the evidence from 48 studies (14 experimental and 34 observational) published between 2016 and 2024 on whether classic psychedelics produce lasting changes in personality. The review concludes that the current evidence supports two relatively robust personality effects of classic psychedelics:

• ↑ Openness to Experience (most consistent finding)

• ↓ Neuroticism (second most consistent finding)

Evidence for changes in other personality traits remains inconclusive, and future research should combine randomized trials with naturalistic studies, include longer follow-up periods, and use a wider range of personality models to better understand how psychedelic experiences influence enduring personality change.

Abstract

Background:

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.

Method:

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.

Results:

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.

Conclusions:

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.

Vicentini AB, de Paula CC, Silva Reis JA, Bouso JC, Hallak JEC, dos Santos RG. Classic psychedelics and personality: An updated systematic review. Journal of Psychopharmacology. 2026;0(0). Read Paper

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