US Pilot Trial of Psilocybin-Assisted Therapy for Veterans' PTSD Reports Early Results

Researchers at Ohio State University have published results from a small open-label pilot trial of psilocybin-assisted therapy in United States military veterans with severe, treatment-resistant post-traumatic stress disorder (PTSD). The study appeared in the Nature Portfolio journal Communications Medicine on 30 July 2026 and was widely reported the same day, including by Reuters.

What the study reported

According to the university’s announcement and the published paper, 12 veterans (nine men and three women) completed an 11-week protocol combining psychotherapy with two doses of synthetic psilocybin — 15 mg and then 25 mg, given two to three weeks apart — alongside roughly eight hours of preparation and six to eight hours of integration therapy. The researchers reported that nine of the 12 participants no longer met diagnostic criteria for PTSD one month after treatment, with an average 27.5-point drop in clinician-rated symptom scores from baseline.

On safety, the authors reported no serious adverse events; the most common side effect was mild headache, and measures of suicidal thinking did not change significantly. First author Stacey Armstrong said that “for a population with severe treatment-resistant PTSD, these results are striking.” The research team screened more than 3,600 applicants to enrol the final 12 participants.

Important caveats

This was a pilot study: it enrolled a small number of participants, was open-label (everyone knew they were receiving psilocybin), and had no control group. The researchers themselves note that uncontrolled pilot studies typically produce larger apparent effects than randomised controlled trials, and that larger controlled studies are needed before conclusions can be drawn. These are preliminary research findings, not evidence that any treatment works.

The Australian picture

The result does not change anything about access in Australia — and the detail matters for readers navigating the Australian system. Under the TGA’s Authorised Prescriber scheme, specifically authorised psychiatrists may prescribe psilocybin only for treatment-resistant depression; for PTSD, the substance that may be prescribed is MDMA. Psilocybin for PTSD is not part of the Australian clinical pathway, so a result like this one could only be pursued here through an approved clinical trial. In the United States, psilocybin remains a Schedule I controlled substance, and this trial was conducted under research authorisation.

Outside those clinical and research settings, psilocybin remains illegal to possess or supply in every Australian state and territory.

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