Four weekly ayahuasca sessions lead to increases in “acceptance” capacities: a comparison study with a standard 8-week mindfulness training program

Recent years have seen renewed interest in psychedelics as treatments for psychiatric conditions, and ayahuasca in particular has attracted attention. The brew combines Banisteriopsis caapi (β-carbolines such as harmine and tetrahydroharmine, which inhibit monoamine oxidase and affect serotonin reuptake) with Psychotria viridis or Diplopterys cabrerana (sources of N,N-dimethyltryptamine, DMT). DMT acts at 5-HT2A and 5-HT1A receptors and, together with the β-carbolines, produces a dream-like altered state often accompanied by vivid imagery and emotional autobiographical recollection. Earlier studies have linked ayahuasca use with lower depressive symptoms and altered activity in brain networks implicated in self-related processing and emotion regulation; the investigators have proposed that some therapeutic effects could relate to enhancements in mindfulness-related capacities such as decentering, non-judgemental awareness and non-reactivity. Wittmann and colleagues designed an exploratory comparison to evaluate whether ayahuasca intake and a standard mindfulness training programme produce overlapping or distinct changes in mindfulness capacities. Specifically, the study compared mindfulness scores before and after four weekly ayahuasca sessions (without an explicit mindfulness aim) versus before and after an 8-week Mindfulness-Based Stress Reduction (MBSR) course (with the explicit goal of cultivating mindfulness). The primary hypothesis was that both interventions would produce improvements in mindfulness-related capacities, while no specific predictions were made for which individual facets would change differentially.

This was an observational, exploratory between-groups comparison including 20 participants, with ten individuals in each group. Groups were similar in age (ayahuasca mean 50.0 years, SD = 14.71; MBSR mean 42.0 years, SD = 11.44; F = 1.84, p = 0.19) and sex (seven females per group). Participants were matched on baseline decentering as measured by the Experiences Questionnaire (EQ); the extracted text reports no baseline differences between groups on the FFMQ facets or the EQ but does not provide detailed baseline scores. The ayahuasca group comprised volunteers who had independently decided to attend four weekly ayahuasca sessions in a non-religious setting in Barcelona. Sessions lasted 6–8 h in a dimly lit room with recorded music; experimenters were present and participants could leave if they wished. Inclusion criteria required abstinence from ayahuasca, medications or illicit drugs for at least 2 weeks prior to the initial assessment, alcohol abstinence for 24 h before assessments, and agreement not to take other drugs during the study. Prior ayahuasca experience was permitted; none reported meditation experience. Questionnaires were administered before the first session and 24 h after the fourth session. The MBSR group consisted of meditation-naïve individuals enrolled in an 8-week standard MBSR course (weekly 2.5 h sessions) taught according to protocol. Training included body-scan, mindful hatha yoga and sitting meditation, encouragement of informal practice in daily activities, a one-day silent retreat between weeks 5 and 6, and provision of guided-meditation CDs for home practice (recommended 45 min daily). Inclusion criteria required no history of ayahuasca use and abstinence from alcohol and other psychoactive drugs as above. Assessments were completed 24 h prior to the first session and after the final session. Mindfulness-related outcomes were assessed using the Spanish versions of two self-report instruments: the Five Facet Mindfulness Questionnaire (FFMQ), which yields five facet scores (Observing, Describing, Acting with awareness, Non-Judging, Non-Reacting), and the Experiences Questionnaire (EQ) for decentering. The MINDSENS Composite Index was also calculated from selected EQ and FFMQ items considered sensitive to meditation practice. Higher scores indicate greater mindfulness or decentering. For analysis, the investigators used ANOVA to test pre-intervention group differences and repeated-measures multivariate ANOVA (for FFMQ subscales) and univariate repeated-measures ANOVAs (for EQ and MINDSENS), with group as the between-subjects factor and time (pre, post) as the within-subjects factor. Post hoc comparisons used Student's t-tests and significance was set at p < 0.05.

Baseline comparisons indicated no significant pre-intervention differences between the ayahuasca and MBSR groups on FFMQ facets or EQ scores (exact baseline values are not presented in the extracted text). The multivariate repeated-measures ANOVA on the five FFMQ facets showed a significant time × group interaction [F(5,14) = 5.16, p = 0.007], indicating differential change across interventions. Univariate tests identified significant time × group interactions favouring MBSR for four FFMQ facets: Observing [F(1,19) = 22.60, p < 0.001], Describing [F(1,19) = 13.61, p = 0.00], Acting with awareness [F(1,19) = 8.52, p = 0.01], and Non-Reacting [F(1,19) = 6.50, p = 0.02]. For Non-Judging there was no significant interaction [F(1,19) = 3.43, p = 0.08]. Post hoc within-group t-tests showed that participants in the MBSR group improved significantly from pre- to post-intervention on all five FFMQ facets: Observing t(9) = -17.14, p < 0.001; Describing t(9) = -9.18, p < 0.001; Acting with awareness t(9) = -18.46, p < 0.001; Non-Judging t(9) = -14.95, p < 0.001; and Non-Reacting t(9) = -8.15, p < 0.001. In contrast, the ayahuasca group showed a significant pre-post improvement only on the Non-Judging subscale: t(9) = -2.67, p = 0.02. No significant pre-post changes were found in the ayahuasca group for Observing t(9) = -1.10, p = 0.29; Describing t(9) = -1.45, p = 0.17; Acting with awareness t(9) = -1.86, p = 0.09; or Non-Reacting t(9) = -1.23, p = 0.25. For decentering (EQ) there was a significant time × group interaction [F(1,18) = 7.87, p = 0.01]. Post hoc tests showed significant pre-post increases in the MBSR group t(9) = -9.63, p < 0.001, but not in the ayahuasca group t(9) = -1.82, p = 0.10. The MINDSENS Composite Index likewise showed a significant time × group interaction [F(1,18) = 21.13, p < 0.001], with significant increases in the MBSR group t(9) = -17.84, p < 0.001, and no significant change in the ayahuasca group t(9) = -1.50, p = 0.17. The extracted text refers to tables and figures for pre-post scores but does not include their numeric content in full.

Wittmann and colleagues interpreted the findings as showing that standard MBSR training produced broader and larger improvements across multiple mindfulness facets, whereas four weekly ayahuasca sessions produced a more circumscribed effect, specifically on the acceptance-related Non-Judging subscale of the FFMQ. The investigators note that Non-Judging reflects a non-evaluative stance toward thoughts and emotions, a capacity that is central to mindfulness practice and relevant to psychological health. They emphasised that the ayahuasca-induced increase in acceptance occurred despite participants taking the tea for personal reasons unrelated to cultivating mindfulness, suggesting a spontaneous enhancement of this domain. The authors situated the result within prior work from their group showing similar increases in acceptance after single ayahuasca sessions and reported longer-term maintenance of Non-Judging at follow-up in earlier studies. Neurobiological evidence from their prior neuroimaging work is invoked: post-acute reductions in glutamate–glutamine in the posterior cingulate cortex (PCC) and increased functional connectivity between the anterior cingulate cortex (ACC) and PCC and between the ACC and medial temporal lobe correlated with Non-Judging increases, linking the psychological change to selective neural modulation. Several limitations acknowledged by the investigators affect interpretation. The study's exploratory and observational design, small sample size (n = 20), non-randomised group allocation and differing participant intentions (ayahuasca users did not seek to train mindfulness, MBSR participants enrolled to enhance mindfulness) may have introduced selection and expectancy effects. Assessments were only conducted before the first and after the final intervention time points, so intermediate trajectories were not captured. Prior ayahuasca experience in the ayahuasca group could have produced ceiling effects, and alkaloid content of the brew was not measured. No placebo or active control for the ayahuasca condition was included, subjective acute effects and participant motivations were not systematically assessed, and no formal medical histories were obtained. In terms of implications, the authors suggest that enhancement of acceptance after ayahuasca could be therapeutically valuable, given acceptance's role in mental health and in exposure-based and mindfulness-based treatments. They proposed that future research should use larger samples, randomised designs, multiple assessment time points, measurement of alkaloid content, and explore whether combining ayahuasca administration with mindfulness-based interventions might potentiate clinical outcomes.

The investigators conclude that the acceptance domain of mindfulness capacities appears particularly sensitive to improvement after ayahuasca, with four sessions producing increases in Non-Judging comparable to those achieved by longer MBSR training in this small sample. They propose that a limited number of ayahuasca sessions could potentially enhance acceptance within psychotherapy, but they caution that the exploratory nature and small sample size of the study limit certainty. Larger, better-controlled studies are required to confirm these findings and to examine whether combining ayahuasca with mindfulness-based approaches would improve therapeutic outcomes.