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Mystical experiences occasioned by the hallucinogen psilocybin lead to increases in the personality domain of openness
Open accessAbstract
A large body of evidence, including longitudinal analyses of personality change, suggests that core personality traits are predominantly stable after age 30. To our knowledge, no study has demonstrated changes in personality in healthy adults after an experimentally manipulated discrete event. Intriguingly, double-blind controlled studies have shown that the classic hallucinogen psilocybin occasions personally and spiritually significant mystical experiences that predict long-term changes in behaviors, attitudes and values. In the present report we assessed the effect of psilocybin on changes in the five broad domains of personality - Neuroticism, Extroversion, Openness, Agreeableness, and Conscientiousness. Consistent with participant claims of hallucinogen-occasioned increases in aesthetic appreciation, imagination, and creativity, we found significant increases in Openness following a high-dose psilocybin session. In participants who had mystical experiences during their psilocybin session, Openness remained significantly higher than baseline more than 1 year after the session. The findings suggest a specific role for psilocybin and mystical-type experiences in adult personality change.
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“A unique and fascinating feature of psychedelics is that intake of one or a few doses is associated with long-lasting effects on behaviors, attitudes, mood, and personality in humans”
From Psychedelics and Neural Plasticity: Therapeutic Implications (2022) · cites this paper as MacLean et al., 2011
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
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“In the few recent studies that measured personality traits, psychedelics were linked to reductions in neuroticism and increases in openness and extraversion across both non-clinical and clinical populations (33, 34).”
From Psychoanalytically informed MDMA-assisted therapy for pathological narcissism: a novel theoretical approach (2025) · cites this paper as [34]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“Post-psychedelic decreases in neuroticism and increases in extroversion, and openness to experience have also been reported [60, 61]; however, these findings have been inconsistent across studies.”
From The psychological processes of classic psychedelics in the treatment of depression: a systematic review protocol (2022) · cites this paper as [61]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“Post-psychedelic decreases in neuroticism and increases in extroversion, and openness to experience have also been reported [60, 61]; however, these findings have been inconsistent across studies.”
From The psychological processes of classic psychedelics in the treatment of depression: a systematic review protocol (2022) · cites this paper as [61]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
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“It has been suggested by some studies that the intensity or quality of the psychedelic experience determines the treatment outcome (52–54).”
From Decreases in State and Trait Anxiety Post-psilocybin: A Naturalistic, Observational Study Among Retreat Attendees (2022) · cites this paper as [53]
Experimental — accuracy not yet measured
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“it has been repeatedly found that psychedelic-induced mystical-type experiences and ego dissolution, the latter a phenomenon characterized by the reduction in self-referential awareness, disruption self-world boundaries, and increased feelings of unity with one’s surroundings (55), correlates with long-term (positive) outcomes (23, 52–54, 56–58).”
From Decreases in State and Trait Anxiety Post-psilocybin: A Naturalistic, Observational Study Among Retreat Attendees (2022) · cites this paper as [53]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
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“Another potential selection bias remains, as studies including treatments with psychedelic substances require a rather high degree of motivation and openness to experience (82) by the participants because of the time-demanding study procedure and the phenomenologically rich nature of psychedelic experiences. This might have contributed to a ceiling effect regarding potential changes in trait”
From Potential therapeutic effects of an ayahuasca-inspired N,N-DMT and harmine formulation: a controlled trial in healthy subjects (2024) · cites this paper as [82]
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“Supporting the view that the psychedelic experience is required for their therapeutic effects, participants who have so-called mystical experiences during psilocybin sessions score significantly higher compared with baseline on the personality trait Openness, and the change is correlated to the intensity of the experience (MacLean et al., 2011).”
From Psychedelics and Neural Plasticity: Therapeutic Implications (2022) · cites this paper as MacLean et al., 2011
The cited source says what the claim attributes to it.
In the citing paper
“Studies using the five-factor model of personality suggest that psilocybin increases openness in healthy participants (34)”
From Psychoanalytically informed MDMA-assisted therapy for pathological narcissism: a novel theoretical approach (2025) · cites this paper as [34]
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In the citing paper
“Mindfulness meditation has been generally deemed safe, but numerous reports exist of acute and long-term negative effects associated with the practise (74, 165–167).”
From Examining the Potential Synergistic Effects Between Mindfulness Training and Psychedelic-Assisted Therapy (2021) · cites this paper as [74]
Experimental — accuracy not yet measuredIn the citing paper
“While it has repeatedly been shown that hallucinogens increase the personality trait openness (85, 86), experimental studies investigating the long-term effects of entactogens and hallucinogens on social cognition and behavior remain scarce.”
From Modulation of Social Cognition via Hallucinogens and “Entactogens” (2019) · cites this paper as [85]
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Citations
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“Finally, designating participants who met the criteria for a complete mystical experience allowed a comparison with previous studies (Griffiths et al., 2008; Griffiths et al., 2006; Pahnke, 1963; Richards et al., 1977; Griffiths et al., 2011).”
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Cited by
Sorted by citations
Nichols, D. E. (2016) · Pharmacological Reviews · doi:10.1124/pr.115.011478 · Cited by 1,762
Carhart-Harris, R. L., Leech, R., Hellyer, P. J., Shanahan, M., Feilding, A., Tagliazucchi, E., Chialvo, D. R., & Nutt, D. (2014) · Frontiers in Human Neuroscience · doi:10.3389/fnhum.2014.00020 · Cited by 1,252
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Metadata
- Authors
- MacLean, K. A., Johnson, M. W., & Griffiths, R. R.
- Affiliations
- Johns Hopkins University (US)
- Corresponding author
- MacLean, Katherine A
- Venue
- Journal of Psychopharmacology
- Publisher
- SAGE Publications
- Published
- 2011-09-28
- Volume
- 25
- Issue
- 11
- Pages
- 1453-1461
- ISSN
- 0269-8811 (ISSN-L)
- 1461-7285
- PMC
- PMC3537171
- OpenAlex
- W2118739111
- Cited by
- 895
- References
- 56
- Citations by year
- 2026: 48 · 2025: 80 · 2024: 92 · 2023: 87 · 2022: 93 · 2021: 100 · 2020: 100 · 2019: 63 · 2018: 56 · 2017: 50 · 2016: 46 · 2015: 23 · 2014: 22 · 2013: 15 · 2012: 17
- FWCI
- 18.60
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Journal of Psychopharmacology (publishedVersion)
- PubMed (publishedVersion)
- Europe PMC (PubMed Central) (acceptedVersion)
- PubMed Central (acceptedVersion)
- Funders
- National Institute on Drug Abuse (R01DA003889, T32DA007209, R01DA03889)
- Topics
- Social Sciences › Psychology › Clinical Psychology › Psychedelics and Drug Studies
- Social Sciences › Psychology › Social Psychology › Paranormal Experiences and Beliefs
- Social Sciences › Health › Religion, Spirituality, and Psychology
- Keywords
- psilocybin, mystical experience, personality change, openness to experience, personality traits, hallucinogens, Big Five personality traits, aesthetic appreciation
- MeSH terms
- Adult, Attitude, Behavior, Double-Blind Method, Extraversion, Psychological, Female, Follow-Up Studies, Hallucinogens, Humans, Longitudinal Studies, Male, Middle Aged, Mysticism, Personality, Psilocybin, Randomized Controlled Trials as Topic, Young Adult
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