Efficacy and Safety of a Single Dose of Psilocybin for Chronic Suicidal Ideation

To evaluate the efficacy, safety, and durability of a single 25-mg dose of a proprietary, synthetic formulation of psilocybin with psychological support for reducing chronic suicidal ideation in a treatment-resistant population. ), and ≥2 prior antidepressant treatment failures received a single 25-mg dose of psilocybin administered within a structured preparatory and integration psychotherapy protocol. The primary outcome was change from baseline in the Modified Scale for Suicidal Ideation (MSSI) at week 3. Secondary outcomes included change in MSSI at weeks 1 and 12 and change in Montgomery-Asberg Depression Rating Scale (MADRS) scores at weeks 1, 3, and 12. Outcomes were analyzed using 1-way repeated-measures analysis of variance with Bonferroni-adjusted pairwise comparisons. = 1.63-1.97). No serious adverse events occurred. In this open-label single-arm study of adults with chronic suicidal ideation and prior treatment failures, a single administration of psilocybin with psychological support was associated with rapid, large-magnitude, and durable reductions in suicidal ideation and depressive symptoms through 12 weeks. These preliminary findings support further evaluation in larger randomized controlled trials. ClinicalTrials.gov Identifier: NCT05220410.