Exploring the Therapeutic Effects of Psychedelics Administered to Military Veterans in Naturalistic Retreat Settings
Veterans attending naturalistic psilocybin or ayahuasca retreats showed significant improvements across eight mental‑health and reintegration measures, with the largest reductions in depression (PHQ‑9, 29.1%) and PTSD (PCL‑5, 26.1%). Psilocybin retreats produced greater gains on most outcomes while ayahuasca yielded slightly larger PTSD improvement; those with worse baseline symptoms benefited most, with some gender-specific differences.
Authors
- Robin Carhart-Harris
- Leor Roseman
- Hannes Kettner
Published
Abstract
Background : Military veterans are at risk of various mental health conditions, with profound implications for post‐deployment quality of life. Current treatment options encounter high dropout rates and non‐responsiveness, and overlook the importance of community building in veterans’ holistic recovery. Preliminary research suggests psychedelics offer therapeutic benefits for depression and post‐traumatic stress disorder (PTSD) in veterans. Integrating psychedelic therapies with a communal retreat setting could provide a more holistic framework for improving veterans’ well‐being. Objectives : To evaluate the effects of psychedelic retreats on mental health and community reintegration in veterans. Methods : Fifty‐eight veterans attended psilocybin or ayahuasca retreats. Participants completed eight mental health questionnaires (e.g. PTSD Checklist, PCL‐5; Patient Health Questionnaire, PHQ‐9), and the Military to Civilian Questionnaire (M2C‐Q) up to 4 weeks both pre‐ and post‐retreat. Paired t ‐tests analyzed changes in outcome responses between time points, and gender and substance‐specific analysis was conducted. Baseline scores were correlated with improvements in PCL‐5 and PHQ‐9 to investigate the relationship between initial symptom severity and percentage improvement following the retreat. Results : Significant improvements were found for all eight outcomes post‐retreat, with the greatest percentage improvements found for depression (PHQ‐9; 29.1%) and PTSD (PCL‐5; 26.1%). Veterans attending psilocybin retreats showed greater improvements in seven out of eight outcomes, whereas ayahuasca retreats demonstrated greater improvements in PCL‐5 scores for PTSD (ayahuasca: 26.4%; Psilocybin 24.8%). Male participants experienced greater improvements across all outcomes apart from the PCL‐5 for PTSD (Male: 24.1%; Female: 32.1%). Higher baseline scores on the PCL‐5 (PTSD) and PHQ‐9 (depression), indicating worse initial mental health, correlated with greater outcome improvements. Conclusions : This is the first study to investigate psychedelic retreats as a holistic therapy for veterans’ mental health alongside community reintegration. Psilocybin and ayahuasca retreats significantly improved veterans’ mental well‐being, quality of life, PTSD, anxiety, depression, sleep, concussion, and post‐deployment reintegration. Participants with more severe symptoms have the potential to benefit most from this intervention, with nuanced insight into improved outcomes based on gender and type of substance. Psychedelic retreats could provide a treatment framework to aid veterans’ recovery by addressing psychological well‐being, communal factors, and reintegration into civilian life.
Research Summary of 'Exploring the Therapeutic Effects of Psychedelics Administered to Military Veterans in Naturalistic Retreat Settings'
Introduction
Military veterans face elevated rates of mental health problems, notably post-traumatic stress disorder (PTSD), frequently co-occurring with depression, substance use and difficulties reintegrating into civilian life. Calnan and colleagues note that existing first-line treatments for PTSD, including manualised psychotherapies and pharmacotherapies, show substantial non-response and dropout, and that many veterans do not access care because of barriers such as stigma and limited availability. The authors argue that conventional approaches often underemphasise community and social support, despite evidence that peer connection and shared experience are important for veterans' recovery. This observational study explores whether psychedelic retreat programmes, which combine administration of psychedelic medicines with group-based preparation, ceremonial dosing and integration, are associated with improvements in mental health and civilian reintegration among veterans. The investigators hypothesised that attendance at a retreat would yield significant, positive changes across multiple measures of psychological distress and reintegration, and that participants with worse baseline scores would show larger proportional improvements. The study therefore examines both symptom change across a battery of questionnaires and the relationship between initial severity and percentage improvement following the retreat experience.
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Study Details
- Study Typeindividual
- Journal
- Compounds
- Topics
- Authors
- APA Citation
Calnan, M., Blest‐Hopley, G., Busch, C., Adams, M., Ruffell, S. G. D., Piper, T., Roseman, L., Kettner, H., & Carhart‐Harris, R. (2025). Exploring the Therapeutic Effects of Psychedelics Administered to Military Veterans in Naturalistic Retreat Settings. Brain and Behavior, 15(7). https://doi.org/10.1002/brb3.70660
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