Embracing Change: Impermanence Acceptance Mediates Differences in Death Processing Between Ayahuasca Users and Non-users

Background: How the human psyche interacts with the theme of death is fundamental to individual and societal life, profoundly influencing cognition, affect, and behavior. Death-related psychological phenomena, such as death anxiety and acceptance, have been shown in clinical studies to be influenced by psychedelic (LSD and psilocybin) interventions. However, the literature lacks a comprehensive assessment of death-related processes in non-clinical settings, the mechanisms underlying long-term changes, and in particular, the effects of ayahuasca-a potent Amazonian psychedelic brew-on these dimensions. Methods: The present cross-sectional study addresses these issues by comprehensively investigating death processing, candidate mechanisms-of-change, and their predictors, in ayahuasca veterans (N=54) compared to non-users (N=53). For this purpose, a battery of questionnaires and behavioral measures targeting various aspects of death processing were employed. These included fear and anxiety of death, death acceptance, death-avoidant behaviors, and accessibility of death thoughts. Tested mediators included personality, ontological afterlife beliefs, trait mindfulness and the construct of impermanence awareness and acceptance. Results: The findings demonstrated lower levels of death anxiety, avoidant behavior and explicit and implicit fear-of-death, as well as greater acceptance of death, for ayahuasca veterans. Mediation analyses revealed that these group differences were not due to demographics, personality, trait mindfulness, ontological beliefs, or impermanence awareness, but rather to impermanence acceptance. Finally, within the ayahuasca group, lifetime ego dissolution experiences, but not ayahuasca intake habits, predicted degree of impermanence acceptance. Conclusions: These findings demonstrate robust and multi-dimensional differences in how death is processed by ayahuasca veterans relative to non-psychedelic users. In contrast to literature suggestions, degree of impermanence acceptance but not ontological beliefs are shown to be the underlying mechanisms-of-change. Finally, the findings support the role of acute subjective ayahuasca experiences in inducing long-term effects. Future (psychedelic and non-psychedelic) interventions can directly target impermanence acceptance for effectively managing existential terror.