Psilocybin and PTSD in veterans: signals from an open pilot

Psiconáutica Editorial Team · August 12, 2026

Researchers at the Center for Psychedelic Drug Research and Education at The Ohio State University have published the results of a pilot study in which twelve veterans with severe post-traumatic stress disorder (PTSD), who had not responded to previous treatments, received psychotherapy combined with two doses of synthetic psilocybin. One month after the second session, nine of twelve met the CAPS-5 remission threshold of 20 or less, not a demonstration of permanent cure.

A pilot with clinical selection and support

The eleven-week protocol combined psychotherapy and two administrations: it included eight hours of preparatory psychotherapy, two dosing sessions (15 mg and then 25 mg, separated by two or three weeks), and six to eight hours of integration across four visits following both doses. The participants had a mean age of 37.7 years and had been struggling with PTSD that had not improved with conventional approaches—a selected sample with specific criteria that limit generalization. For those looking to place this work within the broader map of mushroom research, it is worth reviewing the current state of evidence on psilocybin and magic mushrooms, where most trials to date have focused on depression rather than PTSD.

The data: symptom reduction and safety

According to the article, published July 30 in Communications Medicine, the clinical severity score for PTSD (CAPS-5 scale) fell by an average of 27.5 points, with a very high effect size (Cohen’s d of 2.30) and clear statistical significance. 83% of participants achieved clinically relevant improvement, and nine of twelve (75%) met at-least-50% response and the CAPS-5 remission threshold of 20 or less at the one-month follow-up. The self-reported PCL-5 scale showed an even greater drop, with an average of 40.8 points. Regarding safety, no serious adverse events were recorded; the most common effects were headache, anxiety, and dizziness, and ideation intensity did not change significantly from baseline. Three of twelve reported passive ideation at one month; the small, selected sample cannot estimate population-wide risk or establish suicide prevention.

What this implies

The authors themselves are clear about the study’s limitations: it is an open-label pilot trial, without a placebo group or blinding, involving only twelve people. This type of design tends to produce larger effects than those later confirmed by a randomized, controlled trial. The authors therefore call for larger controlled trials, without establishing that they are underway, before drawing definitive conclusions about how much of the improvement is due to the substance and how much to the intense therapeutic support surrounding it. As with any psychedelic-assisted therapy, the preparation, support, and subsequent integration are inseparable parts of the outcome, something that should be kept in mind from the perspective of harm reduction and responsible use. All in all, for a population struggling with PTSD that does not yield to standard treatments, the observed remission threshold in nine of twelve at one month supports further tests, without implying longer persistence.

Source

• Armstrong, S. B. et al. Safety, feasibility, and preliminary clinical outcomes of psilocybin-assisted therapy for veterans with severe, treatment-resistant PTSD: an open-label pilot clinical trial. Communications Medicine, July 30, 2026.

Educational content written from a harm reduction perspective and with respect for individual freedom. It is not a substitute for advice from a healthcare professional and is not intended to encourage or condemn any drug use.