An investigation of acute physiological and psychological moderators of psychedelic-induced personality change among healthy volunteers

A single high dose of psilocybin (25 mg) given to healthy volunteers who had never used psychedelics reduced neuroticism one month later, consistent with prior research. The reduction was linked to how meaningful the experience felt and to the dread of ego dissolution during the drug's acute effects. Personality was measured with the Big Five Inventory and Big Five Aspect Scale; acute effects were tracked with the Altered States of Consciousness questionnaire and Psychological Insight Scale. Electroencephalography measured alpha power and Lempel-Ziv complexity. The findings suggest that acute psychedelic states can catalyze lasting personality changes in a beneficial direction, with implications for therapy and understanding personality.

Study at a glance

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.