631. PSILOCYBIN AND KETANSERIN VS RTMS IN TREATMENT-RESISTANT DEPRESSION: ENHANCING TOLERABILITY BY MITIGATING PSYCHEDELIC EFFECTS
The International Journal of Neuropsychopharmacology August 1, 2025 Giovanni Martinotti, Clara Cavallotto, G D’andrea et al.
Psilocybin, a psychedelic compound that acts on serotonin receptors, shows promise for treatment-resistant depression, with remission rates up to 70% in some studies. The antidepressant and psychedelic effects may be separable, with the latter linked to 5-HT2A receptors. By co-administering the 5-HT2A antagonist ketanserin, psilocybin's hallucinogenic effects can be minimized, reducing bias from the mystical experience and improving clinical feasibility. A proposed study will randomly assign 68 treatment-resistant depression patients to receive either non-psychedelic psilocybin (two 25 mg doses, preceded by ketanserin) or accelerated repetitive transcranial magnetic stimulation (arTMS). Outcomes will be compared at day 60 using psychometric tests, EEG, and fMRI.