Randomised, double-blind, placebo-controlled crossover study (n=25) testing a single 20 mg oral psilocybin dose versus placebo in healthy volunteers, measuring perturbational complexity index (PCI) with TMS/hd-EEG.
This single-centre, randomized, double-blind crossover study in healthy volunteers applies a single 20 mg oral psilocybin dose versus placebo to investigate altered waking states of consciousness using navigated TMS coupled with high-density EEG (TMS/hd-EEG).
Primary outcome is the perturbational complexity index (PCI) measured at the acute phase (approximately 80 minutes after substance intake) across targeted cortical areas (premotor BA06, midline sensorimotor BA04, superior occipital gyrus/cuneus BA19).
Secondary analyses include resting-state EEG measures (current source density, lagged phase synchronization) and psychometric assessments (5-Dimensional ASC, Hood's Mysticism Scale, PANAS), plus a probabilistic learning task to probe emotional learning rates.
Design: screening visit, two investigational visits in counterbalanced order (psilocybin and placebo), and a 12-week follow-up; approved by KEK Zurich and conducted at Psychiatrische Universitätsklinik Zürich.
Single 20 mg psilocybin session (crossover) with concurrent navigated TMS/hd-EEG measurements.
Single 20 mg oral psilocybin per investigational visit.
Navigated TMS/high-density EEG (TMS/hd-EEG) applied to target cortical areas during acute phase.
Placebo (mannitol) session with same TMS/hd-EEG protocol, crossover design.
Mannitol placebo matching psilocybin session.
Navigated TMS/high-density EEG (TMS/hd-EEG) applied as in active arm.