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 Peer reviewed DOI: 10.1016/j.psyche.2026.100018 via OpenAlex
Summary
Engagement in Shipibo-led ayahuasca retreats significantly improved psychological outcomes for 264 Western participants over 12 months. Participants experienced reductions in Neuroticism and increases in Extraversion, with quality of life enhancing across all measured domains. Most (91.7%) reported long-term benefits, particularly in mental health and personal growth. Minimal adverse effects were noted, and higher baseline psychological distress correlated with increased Neuroticism and reduced decentering, indicating that improving decentering may enhance resilience.
Study at a glance
| Design | prospective longitudinal study |
|---|---|
| Sample size | 264 |
| Population | Western participants at ayahuasca retreats in the Peruvian Amazon |
| Key finding | Participants showed significant reductions in Neuroticism and improvements in quality of life after engaging in ayahuasca retreats. |
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