Effects of ayahuasca on the recognition of facial expressions of emotions in naive healthy volunteers: a pilot, proof-of-concept, randomized controlled trial
Authors:
Juliana Mendes Rocha, Giordano Novak Rossi, FlĂĄvia de Lima OsĂłrio, JosĂ© Carlos Bouso, Gabriela de Oliveira Silveira, Mauricio Yonamine, Alline Cristina Campos, Giuliana Bertozi, Jaime E. CecĂlio Hallak, and Rafael G. dos Santos.
Journal:
Journal of Clinical Psychopharmacology
Year:
2021
About the study
The main objective of this pilot, proof-of-concept, randomized trial was to assess the effects of ayahuasca on the recognition of emotions in facial expressions (REFE), hypothesizing that ayahuasca would modify this parameter.
The trial was conducted from November 2017 to May 2019, evaluating the effects of a single dose of ayahuasca in 20 healthy volunteers. It also assessed the subjective effects of ayahuasca and the trial feasibility and safety.
Compared with the placebo, there were no significant effects of ayahuasca on the REFE task. Because the efficacy of antidepressants seems to be associated with improvements in the REFE and preliminary trials suggest that these drugs have antidepressant effects, further trials with clinical samples are needed to assess their effects on the REFE and in other aspects of social cognition.
Abstract
Background: The recognition of emotions in facial expressions (REFE) is a core aspect of social cognition. Previous studies with the serotonergic hallucinogens lysergic acid diethylamide and psilocybin showed that these drugs reduced the recognition of negative (fear) faces in healthy volunteers. This trial assessed the acute and prolonged effects of a single dose of ayahuasca on the REFE.
Methods: Twenty-two healthy volunteers participated in a pilot, proof-of-concept, randomized trial. Study variables included a REFE task performed before and 4 hours after drug intake, subjective effects (self-reports/observer impressions), tolerability measures (cardiovascular measures, self-reports), and brain-derived neurotrophic factor plasma levels. The REFE task was applied again 1, 7, 14, and 21 days and 3 months after drug intake. Stability of ayahuasca alkaloids during the study was also assessed (room temperature, 18 months).
Findings: Compared with placebo, ayahuasca did not modify the REFE. No significant effects were observed on cardiovascular measures and brain-derived neurotrophic factor levels. Volunteers reported visual effects, tranquility/relaxation, and well-being, with few reports of transient anxiety/confusion. Ayahuasca was well tolerated, producing mainly nausea, gastrointestinal discomfort, and vomiting. A significant time-dependent deterioration of alkaloids was observed, especially for dimethyltryptamine.
Conclusions: Absence of significant effects on the REFE task could be due to lack of effects of ayahuasca (at the doses used), alkaloid degradation, learning effects, and the high educational level of the sample. Further trials with different samples are needed to better understand the effects of ayahuasca and other serotonergic hallucinogens on the REFE. Future trials should improve methods to guarantee the stability of ayahuasca alkaloids.
Photo by Gabriel Voltz on Unsplash.
Categories:
Studies & papers
, Ayahuasca
Tags:
ayahuasca
, scientific research
, study
, DMT
, psychedelics
, hallucinogens
, psychopharmacology
, social cognition