Study Summary

Ten healthy participants were included in this double-blind, randomized, crossover trial investigating the autonomic, neuroendocrine, and immunomodulatory effects of ayahuasca. Participants were administered placebo, 20 mg D-amphetamine, or ayahuasca containing 1 mg/kg of N,N-dimethyltryptamine (DMT) in three study sessions with a washout period of at least one week between sessions. Subjective drug effects were measured using the Hallucinogen Rating Scale (HRS) and the Addiction Research Center Inventory (ARCI) questionnaires. Electrical brain activity was measured using EEG. Body temperature and pupillary diameter were also assessed. Lymphocyte subpopulations were quantified from blood samples, as were serum growth hormone (GH) and prolactin levels which were determined through chemiluminescent and electrochemiluminescent immunoassay. Results show that ayahuasca displayed moderate sympathomimetic effects, significant neuroendocrine stimulation, and a time-dependent modulatory effect on cell-mediated immunity.