Double-blind, randomised, parallel Phase II trial (n=293) of oral psilocybin microdosing (4 mg, 11 doses over six weeks) versus caffeine (60 mg) for moderate major depressive disorder.
This is a double-blind, randomised, parallel-group Phase II trial assessing low-dose oral psilocybin (WP001) taken onsite 11 times over six weeks (every 3–4 days) in participants with moderate major depressive disorder; the active comparator arm receives caffeine 60 mg in identical capsules.
Participants are monitored by a psychiatrist throughout; dosing may be titrated down to 2 mg for safety. A nested neuroimaging (MEG) substudy will recruit up to 80 participants (baseline and first-dose scan), with every third participant invited to participate.
Oral low-dose psilocybin (WP001) capsules given on-site every 3–4 days over six weeks.
Dose may be titrated down to 2 mg if participant shows impairment; dosing supervised on-site; adherence confirmed by staff.
Identical capsules containing caffeine administered on the same schedule as experimental arm.
Caffeine 60 mg in identical capsules (active comparator labelled in protocol as control/placebo).