Symmetrical Global Mental Health (Sym-GMH): Ayahuasca and shipibo traditional medicine for lasting changes in personality and quality of life

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