Randomized, double-blind, placebo-controlled multi-group study (n=140) using single oral doses of psilocybin (0.20–0.315 mg/kg) to probe neural and phenomenological signatures of self-dissolution in healthy volunteers and meditators.
Four placebo-controlled, double-blind study groups test single oral doses of psilocybin to characterise neural, behavioural and phenomenological aspects of self-related processes across EEG, fMRI and biological measures.
Groups 1–3 are healthy volunteer cohorts (EEG or fMRI) and Group 4 compares long-term and novice meditators during a 5-day retreat; outcomes include neuroimaging, psychometrics and blood/saliva biomarkers.
Randomized, placebo-controlled, double-blind, crossover design; EEG cohort.
EEG, questionnaires
100% lactose placebo
Randomized, placebo-controlled, double-blind, fMRI cohort.
fMRI, questionnaires
100% lactose placebo
Randomized, placebo-controlled, double-blind, fMRI cohort (higher dose).
fMRI, questionnaires
100% lactose placebo
Randomized, placebo-controlled, double-blind, meditator vs novice cohort; blood/saliva and subset fMRI.
Blood/saliva, questionnaires; fMRI in 20 subjects
100% lactose placebo
Psilocybin reduced neural responses to surprising tactile stimuli, decreasing activity in frontal regions, visual cortex and cerebellum and attenuating frontal tactile mismatch negativity, consistent with aberrant prediction‑error processing and 5‑HT2A‑mediated disruption of bodily‑self integration. These findings link altered tactile deviancy processing to changes in self‑experience and suggest relevance for psychiatric disorders characterised by aberrant bodily self‑awareness.