Participation in an indigenous Amazonian led ayahuasca retreat associated with increases in nature relatedness - a pilot study

The study used an observational, naturalistic design at the Ayahuasca Foundation (AF), a retreat centre located in the Allpahuayo‑Mishana National Reserve near Iquitos, Peru. Participants were a self-selected sample who travelled to the centre across eight separate retreats of varying lengths (8, 14, 18 and 28 days). A total of 58 participants enrolled after passing the centre's eligibility screening; medical diagnoses were self‑reported and not verified from records. The AF made inclusion decisions independently of the research team. Ethical approval was obtained and the study followed the Declaration of Helsinki. Retreat preparation required a two‑week ‘‘washout’’ from drugs and certain foods to reduce tyramine-related risks with MAOIs. Ceremonies followed an adapted Shipibo format: participants could attend between four and eleven voluntary ayahuasca ceremonies (typically 150–200 ml per serving, dosing left to curandero and participant discretion), each lasting around six hours at night in a communal maloka with one shaman and Western facilitators. Participants completed baseline measures before their first ceremony (at a hotel in Iquitos) and post‑retreat measures the morning after their final ceremony (at the AF). Psychological measures included the six‑item Short Form Nature Relatedness Scale (NR‑6), Beck Depression Inventory II (BDI‑II), State‑Trait Anxiety Inventory (STAI state and trait), Five Facet Mindfulness Questionnaire (FFMQ) and the 30‑item Mystical Experience Questionnaire (MEQ). Reliability analyses reported acceptable to strong internal consistency for these instruments in the sample. The MEQ was administered only at the post‑retreat time point and was used to capture experience across the entire retreat rather than individual sessions. Statistical analyses were conducted in SPSS 27.0. Paired two‑tailed t‑tests compared pre‑ and post‑retreat means and Cohen's d was reported as the effect size measure (with d > .80 considered large). The Holm‑Bonferroni procedure corrected for multiple comparisons. Pearson bivariate correlations assessed relationships among change scores, with an exploratory alpha set at .01. Data screening included Shapiro–Wilk tests for normality and removal of identified outliers; the authors report removal of four outliers from correlation analyses. There was substantial missing data across measures (for example, 24/58 completed the NR‑6 and 47/58 completed the BDI‑II pre/post), which reduced sample sizes for some analyses.

Participation in the indigenous Amazonian ayahuasca retreats was associated with statistically significant pre‑to‑post improvements across the measured domains, with medium to large reported effect sizes. Missingness varied by measure: 47 participants completed pre/post BDI‑II and STAI‑state, 42 completed STAI‑trait, 38 completed the FFMQ, 24 completed the NR‑6, and 50 completed the MEQ at the post‑retreat assessment. For nature relatedness specifically, mean NR‑6 scores increased from a reported baseline of 4.10/5 to 4.36/5 after the retreat. Primary correlation analyses showed statistically significant negative associations between change in NR‑6 and changes in depression (BDI‑II) and both state and trait anxiety (STAI), indicating that increases in nature relatedness were associated with reductions in these clinical symptoms. Change in NR‑6 was also significantly positively correlated with change in mindfulness as measured by the FFMQ. The MEQ change (measured only post‑retreat as the overall retreat score) was not significantly correlated with pre‑post change scores on nature relatedness, mindfulness, depression or anxiety. Despite the lack of correlation, 34 of 42 participants who completed the MEQ (81%) met the study's threshold for a ‘‘complete mystical experience’’ (≥ 60% on each MEQ subscale). No relationships were found between age, gender, or prior lifetime ayahuasca/psychedelic use and the primary outcomes. The number of ceremonies attended did not correlate with changes in nature relatedness, while there was a trend towards an association between longer total retreat duration (days at the centre) and greater increases in nature relatedness. Four outliers were removed from correlation analyses as noted, and the Holm‑Bonferroni correction was applied to control familywise error.

Ruffell and colleagues interpret the findings as preliminary evidence that participating in indigenous Amazonian ayahuasca retreats is associated with increased nature relatedness alongside reductions in depression and anxiety and increases in mindfulness. The reported negative correlations between increases in nature relatedness and reductions in depression and both state and trait anxiety, together with the positive correlation between nature relatedness and mindfulness, led the investigators to propose that enhanced connection to nature may be a clinically relevant pathway linked to mental health benefits observed after retreat participation. The authors position these results within prior research that has linked psychedelics and ayahuasca to shifts in nature‑related attitudes and pro‑environmental behaviour, noting that post‑retreat NR‑6 scores in this sample were higher than typical community baselines reported in other studies. They emphasise the likely influence of contextual factors: traditional shamanic framing, immersion in a biodiverse rainforest setting, enforced disconnection from technology, and time spent at the retreat may mediate increases in nature relatedness independently of or in addition to the pharmacological effects of ayahuasca. The lack of correlation between MEQ scores and outcome changes is discussed in light of methodological issues — notably that the MEQ was used to assess the whole retreat rather than individual sessions — and compared with other studies where mystical experience has predicted clinical outcomes. The authors acknowledge multiple important limitations. This was an uncontrolled, naturalistic pilot with substantial missing data and attrition, limiting statistical power and precluding long‑term follow‑up. The self‑selected, predominantly Western and higher‑income sample reduces generalisability and may be biased by higher baseline openness to experience; ceiling effects are possible because baseline nature relatedness was already high. Measures were collected in different physical settings pre‑ and post‑retreat (hotel versus rainforest centre), which could have influenced responses. The investigators were unable to analyse the chemical constituents of the ayahuasca brew, so dose and alkaloid composition could not be related to outcomes. Given these limitations, the authors call for larger, controlled studies, longer follow‑up, and investigation of mediators and mechanisms; they outline plans for a ‘‘placebo’’ retreat control condition that would mimic the retreat context without serving ayahuasca to help disentangle contextual versus pharmacological effects. Finally, the paper discusses practical implications raised by the authors: simple adjunctive practices such as nature journaling, mindful walking, Shinrin‑Yoku (forest bathing), and mindfulness training may amplify and help sustain increases in nature relatedness after psychedelic retreat participation. The investigators suggest that enhancing nature relatedness could be an additional therapeutic target when administering psychedelics, with potential benefits for both mental health and pro‑environmental attitudes.

The pilot study tentatively suggests that ceremonial ayahuasca retreats in an indigenous Amazonian setting may increase individuals' psychological connection to nature and coincide with improvements in depression, anxiety, and mindfulness, while recognising substantial methodological caveats. Ruffell and colleagues recommend further research to determine the durability of these changes, to identify the specific factors mediating the shift in nature relatedness, and to assess how such effects might be augmented, given the potential relevance for human and planetary health.