Psilocybin in Adults With and Without Autism Spectrum Disorder (PSILAUT)

Case-control repeated-measures crossover design: each participant receives placebo, psilocybin 2 mg and psilocybin 5 mg in separate visits; order pseudorandomised and participants/investigators blinded.

Primary outcomes evaluate serotonin-modulated brain responses using multimodal neuroimaging (fMRI, MRS), EEG and sensory tasks with unimodal and multimodal analyses.

Psilocybin (COMP360) is used as a probe of the serotonin system; UK MHRA determined this is not an IMP clinical trial under EU Directive definitions.