In brief
- A pilot study without a control group treated 12 US veterans with severe, treatment-resistant PTSD.
- With two doses of synthetic psilocybin (15 mg and 25 mg) combined with psychotherapy, nine of the twelve participants no longer met PTSD criteria one month after completion.
- There were no serious adverse events or increases in suicidal ideation; the authors are now calling for a larger, randomized trial.
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 later, nine of the twelve no longer met the diagnostic criteria for the disorder.
A design tailored for the most difficult cases
The eleven-week protocol was not the typical single, carefully staged “trip”: it included eight hours of preparatory psychotherapy, two dosing sessions (15 mg and then 25 mg, separated by two or three weeks), and between six and eight additional hours of integrative therapy following each dose. The participants had a mean age of 37.7 years and had been struggling with PTSD that had not improved with conventional approaches—the profile that typically has the worst clinical prognosis. 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 75% reached complete remission 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 suicidal ideation remained unchanged from the start of the study.
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. For this reason, the team is already planning the next step—a larger study with a comparison group—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, sustained remission in three out of four people is a finding that justifies further research.
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.
