Exploring the Therapeutic Effects of Psychedelics Administered to Military Veterans in Naturalistic Retreat Settings (2025)
July 2025 / Paper authors:
Megan Calnan 1, Grace Blest-Hopley 2, Chris Busch 3, Milly Adams 4, Simon G D Ruffell 5 6 7, Theodore Piper 8, Leor Roseman 9, Hannes Kettner 4 10, Robin Carhart-Harris 4 10
This recent study has shed light on the therapeutic potential of psychedelic retreats for military veterans - highlighting not only symptom relief, but deeper, more integrative healing. Conducted with participants through the Heroic Hearts Project, the research explored how psilocybin or ayahuasca retreats can support psychological recovery and reintegration into civilian life.
Fifty-eight veterans attended international retreats - psilocybin in Jamaica or ayahuasca in Peru - with structured support before, during, and after the experience.
Improvements were observed across the entire cohort, regardless of PTSD diagnosis - suggesting benefits are widespread and may stem from holistic psychological shifts rather than symptom-specific targeting. Psilocybin retreats were more effective for depression, anxiety, post-concussion symptoms, and reintegration, while ayahuasca showed stronger results for PTSD. Veterans with more severe symptoms experienced greater gains, and female participants showed larger PTSD improvements compared to males, who saw more generalised progress.
While these findings are promising, the absence of a placebo or control group prevents clear differentiation between the effects of the substances and the therapeutic impact of the retreat environment itself. Additionally, benefits were only assessed up to four weeks post-retreat, leaving open questions about long-term impact. Finally, no dose data or adverse event details were reported, and the sample lacked demographic diversity.
If future studies are able to rectify these limitations, these early findings may prove fundamental in showing that psychedelic retreats can provide a treatment framework to aid veterans’ recovery by addressing psychological well-being, communal factors, and reintegration into civilian life.