U.S. military veterans and first responders attended a weeklong retreat featuring ayahuasca ceremonies, psychological support, and group activities. Some participants reported improvements in their mental health as research into psychedelics’ potential to treat post-traumatic stress disorder continues to grow. However, clinical evidence remains limited, and the legal status of these treatments in Costa Rica is still complicated.
In September, a group of U.S. military veterans and first responders traveled to Costa Rica to attend an ayahuasca retreat centered on the Amazonian psychoactive brew containing dimethyltryptamine (DMT). The New York Post reported 46 participants, while organizers put the number at 47. Among the attendees were former members of elite military units, including Navy SEALs and Army Rangers, who were looking for new ways to address the psychological toll of their experiences.
The retreat took place September 5–12 at Rythmia Life Advancement Center, located in Guanacaste, near Tamarindo. It was organized in partnership with The Coming Home Project, a nonprofit founded by former Navy SEAL Nate Brown to support veterans and prevent suicide, and funded primarily by the veterans’ charity Birds Eye View Project.
According to the New York Post, the week combined nighttime ayahuasca ceremonies with yoga, meditation, individual and group counseling, and activities designed to help participants process trauma. Before the retreat, organizers reviewed participants’ medical histories, medications, and mental health.
Some attendees said they experienced significant changes afterward. One of them, a 44-year-old firefighter and former Army Ranger identified as Dave L., described a noticeable reduction in the emotional turmoil he had been living with for years. Still, he acknowledged that a single experience does not amount to a cure.
The initiative reflects growing interest in psychedelic-assisted therapy among U.S. veterans, a population particularly affected by post-traumatic stress disorder (PTSD), depression, and other mental health challenges.
According to the U.S. Department of Veterans Affairs’ 2026 annual report, 6,488 veterans died by suicide in 2024, an average of nearly 18 per day.
Against this backdrop, organizations, researchers, and former service members are exploring alternative therapeutic approaches, although early findings still need to be interpreted with caution.
Ayahuasca and PTSD: What Does the Research Show?
Ayahuasca is a traditional Amazonian brew used by Indigenous communities, typically made from plants such as Banisteriopsis caapi and Psychotria viridis. Its chemical composition allows DMT to produce psychoactive effects when taken orally, potentially leading to profound changes in perception, emotion, and introspection.
In recent years, researchers have begun investigating whether ayahuasca could help address various mental health conditions, including PTSD.
A study published in July 2025 in the scientific journal Brain and Behavior examined 58 military veterans who attended ayahuasca or psilocybin retreats in Peru and Jamaica.
Researchers used standardized questionnaires to assess symptoms of depression, anxiety, and PTSD, as well as sleep quality and adjustment to civilian life, among other measures.
The results showed an average 26.1% reduction in PTSD symptom scores and a 29.1% reduction in depression scores following the retreats. Among participants who received ayahuasca, PTSD scores decreased by 26.4%, compared with 24.8% among those who attended psilocybin retreats.
While the findings are encouraging, the study has important limitations. It was observational, with no random assignment or control group, a relatively small sample, and a follow-up period of approximately four weeks after the retreats. As a result, it cannot establish how much of the reported improvement was specifically attributable to the psychedelics rather than therapeutic support, group activities, or other factors.
For the participants in the Costa Rica retreat, no standardized symptom scores, follow-up assessments, or control-group comparisons were reported, according to The Tico Times.
Costa Rica and Ayahuasca: A Complicated Legal Landscape
As international interest in psychedelic retreats grows, Costa Rica is grappling with how to regulate these activities.
In January 2025, Costa Rica’s Ministry of Health issued a health warning against the therapeutic use, consumption, and promotion of ayahuasca and ibogaine without the required health registration.
Authorities emphasized that products intended for medical use must meet legal registration and authorization requirements. They also warned against making therapeutic claims about psychoactive substances without the appropriate approval.
However, in July 2022, Costa Rica’s Ministry of Health allowed Rythmia, the center that hosted the retreat, to continue using ayahuasca for therapeutic purposes pending the publication of specific regulations.
In a February 17, 2025 legal opinion, the Attorney General’s Office declined to endorse the annulment of Rythmia’s authorization, citing procedural deficiencies. It also examined the lack of specific regulations governing ayahuasca use when the original permission was granted.
The Attorney General’s findings did not amount to a blanket approval of ayahuasca as a medical treatment. Instead, they focused on procedural problems with the Ministry of Health’s attempt to revoke Rythmia’s permission.
According to The Tico Times, it remains unclear whether the Ministry of Health has revisited the case since then. The legal document also does not clarify the status of the center’s operating permits at the time of the September 2026 retreat.
The controversy highlights a growing tension: While retreat centers attract international visitors interested in alternative treatments, questions remain about how these practices should be regulated.
Ayahuasca’s Risks and the Importance of Medical Supervision
The potential therapeutic benefits of psychedelics must also be considered alongside their risks.
Ayahuasca can cause nausea, vomiting, increased blood pressure, and intense psychological experiences that some people may find difficult to manage. It can also pose particular risks for individuals with certain psychiatric conditions or cardiovascular diseases.
One of the main medical concerns involves potential drug interactions, particularly with certain serotonergic antidepressants, which can increase the risk of serotonin syndrome, a potentially life-threatening condition.
During the veterans’ retreat in Costa Rica, approximately half of the participants vomited on any given ceremony night, according to Jeff McNairy, Rythmia’s chief medical officer, who spoke to the New York Post.
Although the center describes these reactions as a form of trauma release, vomiting alone is not evidence of clinical improvement.
The center says it has medical professionals and nursing staff available to support participants. However, access to these resources varies across the psychedelic retreat industry, as noted by The Tico Times.
That is why experts stress the importance of reviewing medical and psychiatric histories, assessing potential drug interactions, and ensuring that appropriate emergency response procedures are in place. They also warn that any decision to discontinue antidepressants should be made under professional supervision, never independently just to participate in a ceremony.
The Challenge of Bringing Psychedelics Into Mental Health Care
Accounts from the veterans and first responders reflect both growing interest in psychedelics and the challenges surrounding their potential integration into mental health treatment.
On one hand, personal accounts and preliminary research findings support continued investigation into these substances, particularly for people who have not found sufficient relief through conventional treatments.
On the other, larger controlled clinical trials and long-term follow-up studies are still needed to establish their effectiveness, safety, and potential contraindications.
Costa Rica’s situation raises another issue: how regulatory frameworks could establish clear standards of care, professional training, and participant protections, particularly when retreats are marketed as having therapeutic benefits.
The fact that a group of veterans and first responders traveled abroad seeking relief does not demonstrate that ayahuasca can cure PTSD. But it does illustrate interest in new therapeutic options, as scientists and health authorities work to determine what role these substances may eventually play in medicine.
Cover: Sydtomcat, CC BY-SA 4.0, via Wikimedia Commons // Edited with Canva
