Dr. Armstrong: Post-traumatic stress disorder (PTSD) remains a significant public health concern among U.S. military veterans, who often experience more severe, chronic, and treatment-resistant symptoms than the general population. Existing treatments, including psychotherapy and antidepressant medications, do not work for everyone, and many veterans continue to struggle despite receiving the best available evidence-based care. These treatment gaps underscore the need for novel therapeutic approaches, like psilocybin-assisted therapy (PAT).

PAT has shown promise for several mental health conditions, including depression and anxiety, but it had not previously been studied in a clinical trial focused specifically on military veterans with severe, treatment-resistant PTSD. In this pilot trial, 12 veterans received preparatory psychotherapy, two psilocybin sessions (15 mg and 25 mg administered 2 to 3 weeks apart), and integration therapy following each dosing session.

Regarding safety, the treatment was well tolerated, with no serious adverse events reported. The most common side effects were mild and temporary, including headaches, transient anxiety, and dizziness. Importantly, we observed no increase in suicidal ideation or behavior during the study. Clinically, we found large and significant reductions in PTSD symptoms. Symptom severity decreased substantially from baseline to one month following treatment. Seventy-five percent of participants met criteria for both treatment response and remission from PTSD, and 83% experienced clinically meaningful improvements in symptoms.

PainRelief.com: What are the potential risks of this treatment as well as barriers to wider use?

Dr. Armstrong: Psychedelics do not come without risks. The most common adverse effects observed in this study were headaches, brief anxiety, dizziness, and other short-lived physical or psychological symptoms. While no serious adverse events occurred and cardiovascular measures remained within acceptable safety limits throughout the study, it is important to emphasize that study participants underwent extensive medical and psychiatric screening before enrollment and were under continuous supervision during the dosing sessions. Furthermore, individuals with conditions that could increase risk — including psychotic disorders, bipolar disorder, serious cardiovascular disease, or elevated suicide risk — were excluded from participation.

Additionally, at moderate to high doses, psilocybin and other psychedelics can sometimes produce very challenging experiences, commonly referred to as “bad trips,” as well as profound alterations in consciousness that may lead to ontological shock — a disruption in one’s fundamental understanding of self, reality, or how the world works. In some cases, these experiences can have lasting psychological effects. However, the likelihood of persistent difficulties appears to be reduced when treatment includes thorough preparation, medical supervision, and post-session integration support. Therefore, it is recommended that psilocybin be delivered in medically supervised settings with careful screening and adequate support before and after.

Several barriers currently limit wider implementation. First, because psilocybin remains a controlled substance under federal law, clinical use continues to require substantial regulatory oversight. Second, psilocybin-assisted therapy is not yet FDA-approved, and before approval it will be necessary to complete more large-scale clinical trials to confirm efficacy, better understand long-term outcomes, and determine how this treatment compares with existing interventions. Finally, PAT is resource intensive, involving substantial psychotherapy before and after psilocybin sessions, specialized therapist training, and the involvement of a multidisciplinary team of providers.

PainRelief.com: What should readers take away from your report?

Dr. Armstrong: Our findings provide proof-of-concept that psilocybin-assisted therapy can be delivered safely and feasibly to military veterans with severe, treatment-resistant PTSD when administered within a structured therapeutic framework. The substantial symptom reductions observed suggest that this approach may offer meaningful relief for individuals who have not benefited from currently available treatments. At the same time, this was a small open-label pilot study without a control group, so the results should be understood with the study limitations in mind. While encouraging, these findings are preliminary and require replication in larger, randomized, controlled studies before definitive conclusions about efficacy can be drawn.

PainRelief.com: Is there anything else you would like to add? Any disclosures?

Dr. Armstrong: An interesting finding from our study was that improvements in PTSD symptoms began during the preparatory therapy phase, before psilocybin was administered. Participants who showed greater improvement during preparation tended to experience better outcomes after treatment. This highlights the potential importance of the therapeutic context and suggests that both the psychotherapy and the pharmacological effects of psilocybin may contribute to clinical outcomes. Above all, we owe our deepest thanks to the veterans who participated in this study. Their willingness to share their experiences made this research possible and contributes to the development of new treatment options for others living with PTSD.

Disclosures: Stacey B. Armstrong and Rafaelle Lancelotta are board members of Source Research Foundation, and Alan K. Davis is the organization’s president. The study was conducted at The Ohio State University’s Center for Psychedelic Drug Research and Education and was supported by institutional research infrastructure and collaborators.

Citation:
Armstrong SB, Levin AW, Sepeda ND, 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. Commun Med. 2026;6:411. https://doi.org/10.1038/s43856-026-01767-4

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Last Updated on August 3, 2026 by PainRelief.com