BACKGROUND: 5-methoxy-N,N-dimethyltryptamine (hereinafter referred to as 5-MeO-DMT) is a psychedelic substance found in the secretion from the parotoid glands of the Bufo alvarius toad. Inhalation of vapor from toad secretion containing 5-MeO-DMT has become popular in naturalistic settings as a treatment of mental health problems or as a means for spiritual exploration. However, knowledge of the effects of 5-MeO-DMT in humans is limited. AIMS: The first objective of this study was to assess sub-acute and long-term effects of inhaling vapor from dried toad secretion containing 5-MeO-DMT on affect and cognition. The second objective was to assess whether any changes were associated with the psychedelic experience. METHODS: Assessments at baseline, within 24 h and 4 weeks following intake, were made in 42 individuals who inhaled vapor from dried toad secretion at several European locations. RESULTS: Relative to baseline, ratings of satisfaction with life and convergent thinking significantly increased right after intake and were maintained at follow-up 4 weeks later. Ratings of mindfulness also increased over time and reached statistical significance at 4 weeks. Ratings of depression, anxiety, and stress decreased after the session, and reached significance at 4 weeks. Participants that experienced high levels of ego dissolution or oceanic boundlessness during the session displayed higher ratings of satisfaction with life and lower ratings of depression and stress. CONCLUSION: A single inhalation of vapor from dried toad secretion containing 5-MeO-DMT produces sub-acute and long-term changes in affect and cognition in volunteers. These results warrant exploratory research into therapeutic applications of 5-MeO-DMT.

1st Faculty of Medicine Charles University Prague Czech Republic

3rd Faculty of Medicine Charles University Prague Ruská 87 10000 Prague 10 Czech Republic

Department of Clinical Sciences Faculty of Psychology and Neuroscience Maastricht University Maastricht The Netherlands

Department of Neuropsychology and Psychopharmacology Faculty of Psychology and Neuroscience Maastricht University Maastricht The Netherlands

Department of Organic Chemistry University of Chemistry and Technology Prague Czech Republic

Forensic Laboratory of Biologically Active Substances Department of Chemistry of Natural Compounds University of Chemistry and Technology Prague Czech Republic

Innate Path Lakewood CO USA

National Institute of Mental Health Prague Czech Republic

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