Psychedelics and mindfulness: A systematic review and meta-analysis

Background and aims: The benefits of classic serotonergic psychedelics (e.g. psilocybin, LSD, DMT, ayahuasca) are becoming more widely known with the resurgence in research in the past decade. Furthermore, the benefits of mindfulness are well documented. However, no systematic reviews have examined linkage of mindfulness and psychedelics use. The aim of this systematic review is to explore the link between psychedelics and characteristics of mindfulness. Methods: We conducted a systematic search across multiple databases, inclusive of grey literature and backwards/forward-citation tracking, on the 18 January 2021. The search strategy included terms relating to mindfulness and psychedelics, with no restriction on clinical or non-clinical conditions. Study quality was assessed. An exploratory random-effects meta-analysis was conducted on pre-post mindfulness data relative to psychedelic ingestion. Results: Of 1805 studies screened, 13 were included in the systematic review. There was substantial variability in participant characteristics, psychedelic administration method and measurement of mindfulness. The ingestion of psychedelics is associated with an increase in mindfulness, specifically relating to domains of acceptance, which encompasses non-judgement of inner experience and non-reactivity. The meta-analysis of a subset of studies (N = 6) showed small effects overall relative to ayahuasca ingestion, increasing mindfulness facets of non-judgement of inner experience and non-reactivity, as well as acting with awareness. Conclusions: Further methodologically robust research is needed to elucidate the relationship between psychedelics and mindfulness. However, mindfulness and specific facets relating to acceptance have been shown to increase following ingestion of psychedelics in a number of studies.