Phase IIb randomised, double-blind trial (n=96) comparing two doses of psilocybin (25 mg vs 5 mg) plus psychological support; two doses given one month apart with outcomes over 33 weeks in adults with severe GAD.
Multicentre, randomised, double-blind parallel-group trial comparing efficacy and safety of two oral psilocybin doses (25 mg vs 5 mg) given in two dosing sessions one month apart, with stratification by SSRI status and follow-up to 33 weeks.
Primary outcome is change in HAM-A at week 8; secondary outcomes include GAD-7, PHQ-9, SDS, WEMWBS, healthcare utilisation, EEG/ECG measures (resting-state, emotional faces, oddball), and safety/tolerability across acute and follow-up visits.
Participants may be taking permitted stable SSRIs; capsules are matched for appearance and masking efficacy will be assessed at each dosing session.
High-dose arm receiving two oral 25 mg psilocybin capsules with psychological support, one month apart.
Two doses, one month apart; capsules matched for weight/appearance with 5 mg.
Low-dose comparator receiving two oral 5 mg psilocybin capsules with psychological support, one month apart.
Two doses, one month apart; capsules matched for weight/appearance with 25 mg.