• Posted July 31, 2026

Psilocybin Therapy Helps Ease Veterans' Severe PTSD, Pilot Study Finds

U.S. Army veteran Zachariah Collett served a 28-month combat tour in Iraq that left deep scars on his psyche.

After his medical retirement at age 25, due in part to post-traumatic stress disorder (PTSD), Collett suffered from nightmares and a short fuse. He felt constantly on guard and always angry.

“I was just absolutely tortured by the internal struggle, the internal dialogue, the noise inside my head and the inability even to just be still,” Collett, from Washington Court House, Ohio, said in a news release.

Collett eventually found help from an unexpected source — psilocybin.

The psychedelic chemical found in “magic mushrooms” helped Collett reclaim his inner peace as part of a clinical trial testing the drug's effectiveness in treating severe PTSD among military veterans.

For the new pilot trial, researchers recruited 12 veterans with severe PTSD that hadn’t been helped using psychotherapy or antidepressants.

The 11-week trial combined eight hours of psychotherapy followed by two doses of synthetic psilocybin, researchers reported July 30 in the journal Communications Medicine. Six to eight more hours of therapy followed the psilocybin sessions.

The combo therapy caused PTSD symptoms to fall by more than half, dropping from an average of nearly 40 points to just over 12 points on a clinical scale, researchers report.

Of the 12 veterans participating in the clinical trial, nine were in remission from PTSD by one month after the study’s end, researchers said.

“For a population with severe treatment-resistant PTSD, these results are striking,” lead researcher Stacey Armstrong, said in a news release. She is associate director of the Center for Psychedelic Drug Research and Education (CPDRE) at the Ohio State University College of Social Work, in Columbus.

Psilocybin is being tested as a potential treatment for many different mental health problems, including depression and PTSD, researchers said in background notes.

The researchers stressed that the observed improvements weren’t wholly dependent on psilocybin. They believe that the rigorous psychotherapy schedule each veteran engaged in was key, with PTSD symptoms beginning to decline even before the vets took psilocybin.

“There is this big question in the psychedelic therapy field right now about how much of this is a drug effect, how much of this is a therapy effect, and how much is a combination of the two,” said senior researcher Alan Davis, in a news release.

However, PTSD symptoms did experience a much larger reduction after the two psilocybin doses, Davis noted. He directs the CPDRE and is an associate professor of social work at Ohio State.

“This treatment is more than just a drug,” said Davis, “The drug itself is a catalyst for the deep work that opens a window for people to perhaps access things they wouldn’t be able to access emotionally otherwise, and what that does is catalyze the therapeutic process after.

“That’s where the magic actually happens,” Davis continued. “It happens in the therapy, and in the changes that people start to make in their lives after the treatment’s concluded.”

Three years out from the treatment, veteran Collett says psilocybin had a profound effect on him, his family and his marriage.

“For the first six months to a year, I felt like I had this fantastic set of training wheels while I’m relearning the way to act in situations,” he said. “That’s the great thing about this medicine. It’s gentle and it allowed me the space to rediscover, or discover, things I didn’t know I was capable of doing.

“It allowed me the opportunity to create peace, and stillness, and acceptance, and forgiveness and grace — all those things opposite of resentment and anger and hatred,” Collett continued. “It’s rather beautiful.”

Researchers acknowledged that these sorts of small-scale pilot studies tend to produce larger benefits than standard clinical trials. They hope to follow up with a larger clinical trial.

“Recognizing the tools that we have don’t work so well and recognizing the significant burden of PTSD in the United States carried by our servicemen and women and veterans, this seemed like the right direction to go,” Armstrong said. “Too many veterans right now are suffering despite the treatments that we have, and that’s why we feel that this research is important.”

More information

Johns Hopkins Medicine has more on psychedelics research and psilocybin therapy.

SOURCES: Ohio State University, news release, July 30, 2026; Communications Medicine, July 30, 2026