An investigation of acute Physiological and Psychological Moderators of Psychedelic-induced Personality Change among Healthy Volunteers
This re-analysis of a single-blind, fixed-order trial (n=28) investigates the effects of a single high-dose psilocybin (25 mg) on personality traits in psychedelic-naïve healthy volunteers. It finds significant reductions in neuroticism one month post-administration, moderated by subjective experience meaningfulness and ego dissolution, suggesting psilocybin catalyses lasting personality changes with therapeutic potential.
Authors
- Robin Carhart-Harris
- David Erritzoe
- Brandon Weiss
Published
Abstract
This study investigated the effects of a single high-dose of psilocybin on personality traits in psychedelic-naïve healthy volunteers. These data originate from a larger within-subjects fixed-order design trial, where a single high dose of psilocybin (25 mg) was administered in a psychologically supportive setting and was compared against a (one-month) prior, 1 mg ‘placebo’ dose. Personality shifts were assessed by the Big Five Inventory and the Big Five Aspect Scale, while the Altered States of Consciousness questionnaire (5D-ASC) and the Psychological Insight Scale gauged the acute psychological effects of the substance. Electroencephalography provided neurophysiological insights, specifically examining alpha power and Lempel-Ziv complexity (LZc). Results indicated significant reductions in neuroticism one month after 25 mg psilocybin administration, a finding consistent with prior studies. Reductions in neuroticism were moderated by the subjective meaningfulness of the psychedelic experience, as well as by the dread of ego dissolution subscale of the 5D-ASC, suggesting a relationship between acute drug effects and enduring personality alterations. Thus, this study substantiates the role of acute psychedelic states in catalysing lasting personality transformations in a generally beneficial direction, with broader implications for therapeutic applications and understanding of personality dynamics.
Research Summary of 'An investigation of acute Physiological and Psychological Moderators of Psychedelic-induced Personality Change among Healthy Volunteers'
Introduction
Classical psychedelics such as psilocybin produce intense, transient alterations in consciousness, perception and emotion and have been associated with persistent psychological changes, notably in personality domains. Cross-sectional comparisons of regular psychedelic users and controls suggest higher openness and lower harm avoidance among users, but these designs cannot establish causality. Interventional and observational pre-post studies have produced mixed results, with the strongest and most consistent evidence supporting reductions in neuroticism (or harm avoidance) and, less consistently, increases in openness. There is limited work linking the acute psychological and neurophysiological states during psychedelic experiences to these longer-term personality shifts. Godfrey and colleagues set out to test whether a single high dose of psilocybin (25 mg) administered in a psychologically supportive laboratory context produces enduring personality change in psychedelic‑naïve healthy volunteers, and whether acute subjective or electrophysiological measures recorded during the experience moderate any such change. The investigators used a within‑subjects, fixed‑order design in which a sub‑perceptual 1 mg dose (quasi‑placebo) preceded the 25 mg session by one month; hypotheses focused on an increase in openness and a decrease in neuroticism after 25 mg only, with exploratory analyses testing acute psychological and EEG markers (including alpha power and Lempel‑Ziv complexity, LZc) as potential moderators.
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Study Details
- Study Typeindividual
- Journal
- Compounds
- Topics
- Authors
- APA Citation
Godfrey, K., Weiss, B., Zhang, X., Spriggs, M., Peill, J., Lyons, T., Carhart-Harris, R., & Erritzoe, D. (2025). An investigation of acute Physiological and Psychological Moderators of Psychedelic-induced Personality Change among Healthy Volunteers. Neuroscience Applied, 4, 104092. https://doi.org/10.1016/j.nsa.2024.104092
References (53)
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Barrett, F. S., Doss, M. K., Sepeda, N. D. et al. · Scientific Reports (2020)
Barrett, F. S., Johnson, M. W., Griffiths, R. R. · Personality and Individual Differences (2017)
Bouso, J. C., González, D., Fondevila, S. et al. · PLOS ONE (2012)
Rodríguez-Fornells, A., Ribeiro, S., Sanches, R. F. et al. · European Neuropsychopharmacology (2015)
Carhart-Harris, R. L., Giribaldi, B., Watts, R. et al. · New England Journal of Medicine (2021)
Carhart-Harris, R. L., Bolstridge, M., Rucker, J. et al. · Lancet Psychiatry (2016)
Carhart-Harris, R. L., Erritzoe, D., Haijen, E. C. H. M. et al. · Psychopharmacology (2017)
Carhart-Harris, R. L., Kaelen, M., Bolstridge, M. et al. · Psychological Medicine (2016)
Carhart-Harris, R. L., Muthukumaraswamy, S., Roseman, L. et al. · PNAS (2016)
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Show all 53 referencesShow fewer
de Wit, H., Molla, H. M., Bershad, A. K. et al. · Addiction Biology (2022)
Dressler, H. M., Bright, S. J., Polito, V. · Journal of Psychedelic Studies (2021)
Erritzoe, D., Roseman, L., Nour, M. R. et al. · Acta Psychiatrica Scandinavica (2018)
Erritzoe, D., Smith, J. M., Fisher, P. M. et al. · Journal of Psychopharmacology (2019)
Erritzoe, D., Timmermann, C., Godfrey, K. et al. · Nature Mental Health (2024)
Griffiths, R. R., Johnson, M. W., Richards, W. A. et al. · Journal of Psychopharmacology (2017)
Griffiths, R. R., Richards, W. A., Mccann, U. et al. · Journal of Psychopharmacology (2006)
Haijen, E. C. H. M., Kaelen, M., Roseman, L. et al. · Frontiers in Pharmacology (2018)
Hartogsohn, I. · Journal of Psychopharmacology (2016)
Jiménez-Garrido, D. F., Gómez-Sousa, M., Ona, G. et al. · Scientific Reports (2020)
Kiraga, M. K., Kuypers, K. P. C., Uthaug, M. V. et al. · Frontiers in Psychiatry (2022)
Kiraga, M. K., Mason, N. L., Uthaug, M. V. et al. · Frontiers in Pharmacology (2021)
Knudsen, G. M. · Neuropsychopharmacology (2022)
Kopra, E., Cleare, A. J., Rucker, J. et al. · Journal of Affective Disorders (2022)
Kometer, M., Pokorny, T., Seifritz, E. et al. · Psychopharmacology (2015)
Kometer, M., Vollenweider, F. X. · Behavioral Neurobiology of Psychedelic Drugs (2016)
Lebedev, A. V., Kaelen, M., L€ Ovd En, M. et al. · Human Brain Mapping (2016)
Lebedev, A. V., L€ Ovd En, M., Rosenthal, G. et al. · Human Brain Mapping (2015)
Maclean, K. A., Johnson, M. W., Griffiths, R. R. · Journal of Psychopharmacology (2011)
Madsen, M. K., Fisher, P. M., Stenbæk, D. S. et al. · European Neuropsychopharmacology (2020)
Dos Santos, R. G., Rocha, J. M., Rossi, G. N. et al. · Frontiers in Psychiatry (2021)
Murphy, R., Murphy-Beiner, A., Kettner, H. et al. · Frontiers in Pharmacology (2022)
Murray, C., Frohlich, J, Haggarty, C. J., Tare, I. et al. · Neuropsychopharmacology (2024)
Muthukumaraswamy, S. D., Carhart-Harris, R. L., Moran, R. J. et al. · Journal of Neuroscience (2013)
Netzband, N., Ruffell, S., Linton, &. S. et al. · Psychopharmacology (2020)
Nour, M. R., Evans, J., Carhart-Harris, R. L. · Journal of Psychoactive Drugs (2017)
Pallavicini, C., Cavanna, F., Zamberlan, F. et al. · Journal of Psychopharmacology (2021)
Peill, J. M., Trinci, K. E., Kettner, H. et al. · Journal of Psychopharmacology (2022)
Perkins, D., Pagni, B. A., Sarris, J. et al. · Frontiers in Pharmacology (2022)
Bouso, J. C., Révész, D., Ona, G. et al. · Frontiers in Psychiatry (2021)
Rocha, J. M., Rossi, G. N., de Lima Osório, F. et al. · Journal of Clinical Psychopharmacology (2021)
Roseman, L., Haijen, E. C. H. M., Idialu-Ikato, K. et al. · Journal of Psychopharmacology (2019)
Roseman, L., Nutt, D. J., Carhart-Harris, R. L. · Frontiers in Pharmacology (2018)
Schartner, M., Carhart-Harris, R. L., Barrett, A. B. et al. · Scientific Reports (2017)
Schmid, Y., Liechti, M. E. · Psychopharmacology (2017)
Studerus, E., Gamma, A., Kometer, M. et al. · PLOS ONE (2012)
Szigeti, B., Kartner, L., Blemings, A. et al. · eLife (2021)
Szigeti, B., Nutt, D. J., Carhart-Harris, R. L. et al. · Scientific Reports (2023)
Szigeti, B., Weiss, B., Rosas, F. E. et al. · Psychological Medicine (2024)
Timmermann, C., Roseman, L., Schartner, M. et al. · Scientific Reports (2019)
Weiss, B., Ginige, I., Shannon, L. et al. · Psychological Medicine (2023)
Weiss, B., Miller, J. D., Carter, N. T. et al. · Scientific Reports (2021)
Nygart, V., Pommerencke, L. M., Carhart-Harris, R. L. et al. · Frontiers in Psychology (2021)
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