Single-dose psilocybin for U.S. military Veterans with severe treatment-resistant depression: first-in-kind open-label pilot study

Psilocybin was tested in U.S. military Veterans with severe treatment-resistant depression (TRD) in a first-in-kind open-label pilot design. Fifteen Veterans received 25 mg psilocybin with psychological support, and investigators measured depressive symptoms using the Montgomery-Åsberg Depression Rating scale (MADRS). At Week 3, 60% met response (at least a 50% MADRS reduction) and 53% met remission (MADRS 10 or below). By Week 12, 47% maintained response and 40% maintained remission. Co-morbid PTSD did not significantly change outcomes, and the degree of psychedelic experience did not correlate with depression improvement. No unexpected side effects or adverse events were reported, though limitations included the small sample size and lack of masking. Trial registration: NCT04433858.