Effects of psilocybin on personality, psychiatric symptoms, and values: Exploring mediating effects of the acute psychedelic experience
Journal of Psychopharmacology – January 26, 2026
Source: OpenAlex
Summary
Psilocybin, a potent hallucinogen, significantly shifts personal values, a key area in psychology. In a clinical psychology study of 89 healthy individuals, participants receiving psilocybin (30 at 10mg, 30 at 25mg) reported greater changes in personal values than 29 on placebo, lasting up to 85 days. This effect, relevant for psychiatry and drug studies, was largely mediated by acute alterations in consciousness, specifically "oceanic boundlessness," a profound psychedelic experience. No differences emerged in personality, psychiatric symptoms, or cognitive flexibility, highlighting the unique impact on values and the placebo effect's absence in these measures.
Abstract
Background: Changes in well-being, personality, and personal values have been documented post-psilocybin; however, evidence from placebo-controlled trials is limited. Aims: To examine the effects of psilocybin versus placebo on psychiatric symptoms, personality, and personal values in healthy participants. Potential mediators were also explored. Methods: This secondary analysis used data from a phase I, double-blind, randomised, placebo-controlled trial testing a single dose of 10 mg ( n = 30) or 25 mg psilocybin ( n = 30) versus an inert placebo ( n = 29) in 89 healthy participants. Effects of psilocybin on personality (Neo Five-Factor Inventory; NEO-FFI), psychiatric symptoms (Symptom Checklist-90; SCL-90), and values (Life Changes Inventory; LCI) at short- (day 8) and long-term follow-up (day 85) were analysed using mixed-effects models. Group differences in cognitive flexibility (Intra-Extra Dimensional Set Shift task; IED) at day 8 were analysed using a Kruskal–Wallis test. Potential mediating effects of the acute psychedelic experience (Five-Dimensional Altered States of Consciousness Questionnaire; 5D-ASC) were explored. Results: No between-group differences were found on the NEO-FFI, SCL-90, or IED. Both psilocybin groups showed greater LCI absolute change scores at both follow-up points compared to placebo. The 5D-ASC oceanic boundlessness subscale partially mediated these changes. Oceanic boundlessness also fully or partially mediated differences across several LCI subscales, and auditory alterations mediated differences on one subscale. Conclusions: The acute psychedelic experience, namely oceanic boundlessness and, to a lesser extent, auditory alterations, mediates self-reported changes in values in healthy volunteers. Findings from this exploratory study are tentative and should be replicated in larger samples.