In the first psilocybin study run specifically in veterans, most participants' treatment-resistant depression improved three weeks after a single dose.
A 2025 study gave a single dose of psilocybin to U.S. military veterans with severe, treatment-resistant depression.
Fifteen U.S. military veterans with severe depression that hadn't responded to other treatments received a single 25 mg dose of psilocybin, with their depression measured three weeks later. About 6 in 10 (60%) had a major drop in symptoms, and about half (53%) improved enough to count as remission. This was the first psilocybin trial run specifically in veterans — an encouraging early signal. But it was small, with no comparison group and no blinding, so the improvement can't be separated from placebo or expectation, and it only measured three weeks out.
This open-label, single-arm trial (n=15) gave U.S. military veterans with severe treatment-resistant depression a single 25 mg dose of psilocybin. The primary outcome was change in the Montgomery-Asberg Depression Rating Scale (MADRS) at three weeks. At that point, 60% met response (>=50% reduction) and 53% met remission (MADRS <=10).
The response and remission rates are high, but the evidence is preliminary. The sample is very small (n=15); there was no control group and no blinding, so improvement cannot be separated from placebo response or expectancy; follow-up was only three weeks; and participants were a treatment-resistant group. The authors themselves note the small sample and the uncontrolled, unblinded design.
This was the first psilocybin trial conducted specifically in U.S. military veterans. A separate analysis of the same cohort tracked longer-term outcomes, finding benefits that waned after roughly six to nine months (Ellis et al., 2025), and a secondary analysis reported improvements in anxiety, quality of life, and functioning (Kelly et al., 2026). It sits within a broader psilocybin-for-depression literature built largely on non-veteran samples.
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