Symmetrical Global Mental Health (Sym-GMH): Ayahuasca and shipibo traditional medicine for lasting changes in personality and quality of life
José Carlos Bouso, Óscar Andión, Jordi Cantillo, Irene Pérez, Magí Farré, Jordi E. Obiols, Débora González
Psychedelics April 20, 2026 DOI: 10.1016/j.psyche.2026.100018 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Prospective longitudinal study Peer reviewed |
|---|---|
| Sample size | 264 |
| Population | Western participants who engaged in Shipibo-led ayahuasca retreats at the Temple of the Way of Light in the Peruvian Amazon |
| Intervention | Shipibo-led ayahuasca retreats |
| Duration | 12-month follow-up |
| Topics | Ayahuasca |
| Keywords | Global mental health Personality Quality philosophy Clinical psychology Psychotherapist Alkaloids |
| Key findings | Shipibo traditional medicine practices, when contextually preserved and ethically applied, led to lasting improvements in personality, quality of life, and decentering capacities with minimal adverse effects in Western participants. |
Abstract
The Symmetrical Global Mental Health (Sym-GMH) paradigm proposes a reciprocal integration between traditional and Western medical systems. This prospective, longitudinal study evaluates the psychological outcomes of 264 Western participants who engaged in Shipibo-led ayahuasca retreats at the Temple of the Way of Light in the Peruvian Amazon. Over a 12-month period, participants completed assessments of personality (NEO-FFI), quality of life (WHOQOL-BREF), decentering (EQ-Decentering), and psychiatric symptoms (SA-45). The results showed significant reductions in Neuroticism and Openness to Experience and increase in Extraversion, with no significant change in Agreeableness and Conscientiousness. Quality of life improved across all measured domains, and decentering capacities increased significantly with moderate to high effects size. Most participants (91.7%) reported long-term benefits, primarily in spiritual well-being, mental health, and personal growth. Adverse effects were minimal (2.3%). Despite higher frequency of last month substances use was observed, increase on the prevalence was only observed for tobacco. Extraversion at baseline predicted improvements across all quality-of-life domains. Notably, higher baseline psychological distress was associated with higher Neuroticism and lower decentering, suggesting that enhancing decentering may serve as a resilience factor. These findings suggest that Amazonian traditional practices, when contextually preserved and ethically applied, can offer meaningful contributions to mental health in Western populations. The study supports the integration of traditional systems within global mental health frameworks, advocating for a non-extractive, culturally respectful, and evidence-based exchange between healing paradigms. • Shipibo traditional medicine showed lasting mental health improvements • Neuroticism decreased; Extraversion increased • Quality of life improved in all WHOQOL-BREF domains at 12-month follow-up • Decentering capacity increased; linked to reduced distress and higher resilience • Supports ethical integration of traditional medicine in global mental health
Comparable studies
Other observational and cohort studies on ayahuasca, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Antidepressant effects of a single dose of ayahuasca in patients with recurrent depression: a preliminary report Patients with a depressive disorder | 2015 | Observational study | |
| The Psychedelic State Induced by Ayahuasca Modulates the Activity and Connectivity of the Default Mode Network Experienced subjects | 2015 | Observational cohort | n = 10 |
| Human Psychopharmacology of Hoasca, A Plant Hallucinogen Used in Ritual Context in Brazil Long-term members of a syncretic church that uses hoasca as a psychoactive sacrament... | 1996 | Observational cohort with matched controls | n = 30 |
| Ayahuasca-Assisted Therapy for Addiction: Results from a Preliminary Observational Study in Canada Rural aboriginal population | 2013 | Observational study | |
| Personality, Psychopathology, Life Attitudes and Neuropsychological Performance among Ritual Users of Ayahuasca: A Longitudinal Study Regular ayahuasca users and active controls in non-ayahuasca religions | 2012 | Observational cohort | n = 242 |
Citations in the library
Cites 58
- Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin Proceedings of the National Academy of Sciences January 23, 2012
- Psychedelics Promote Structural and Functional Neural Plasticity Cell Reports June 1, 2018
- Mystical experiences occasioned by the hallucinogen psilocybin lead to increases in the personality domain of openness Journal of Psychopharmacology September 28, 2011
- Rapid antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression: a randomized placebo-controlled trial Psychological Medicine June 15, 2018
- Increased Global Functional Connectivity Correlates with LSD-Induced Ego Dissolution. Current Biology April 13, 2016
and 53 more in the library