ICEERS

Though no serious psychological adverse events have been reported in the clinical studies after the acute administration of Ayahuasca, a note of caution should be made regarding Ayahuasca safety. The studies were mainly performed in healthy young volunteers who had extensive experience in psychedelic drug use, so the conclusions cannot be extrapolated to Ayahuasca-naïve individuals. Although in the clinical studies only there is reported one subject that suffered an episode of disorientation (1), a case report describes a patient who presented a psychotic breakdown after acute Ayahuasca intake who needed antipsychotic medication until his remission (2). Other few cases of psychiatric adverse reactions, including psychotic disorders, have been reported following acute Ayahuasca ingestion (3). Though the prevalence of those adverse psychiatric reactions is statistically anecdotal, and the psychological safety margin of Ayahuasca is quite acceptable (4), it is necessary to take them into account in order to get a complete picture of the possible negative psychiatric risks of Ayahuasca use. 

On the other hand, other studies have reported significant reductions of minor psychiatric symptoms and positive changes in behavior in the four days following the first ayahuasca experience (5). Another study found reductions in the scores of panic and hopelessness one hour after ayahuasca ingestion, as compared to baseline (6). One final study found improvement in several psychological measures in a six month follow-up study in subjects after their first Ayahuasca experience, finding positive correlations between some of the psychological changes and the frequency of Ayahuasca use, and negatively with the wash-out period (7).

There are some researches that focused on potential psychiatric and cognitive sequels in long term Ayahuasca users both in adults (8) (9) and in adolescence population (10) (11). Neither psychopathological alterations nor neuro-cognitive deficits were found in the published studies. It should be noted however that the participants studied may have suffered a self-selection bias, since the participants may have been those who did not experience any negative neuropsychiatric consequences derived from their maintained Ayahuasca use. Subjects experiencing adverse consequences might have given up Ayahuasca use and therefore not accessible as participants. In that way, it would be desirable to include in future studies people who used Ayahuasca regularly in the past but decided to discontinue its use. 

Lastly, one recent study carried out in two different samples of a total of 112 long term Ayahuasca users compared to 115 matched controls along one year of follow-up, found that Ayahuasca users take less drugs of abuse than controls, including alcohol, and concluded that “the ritual use of Ayahuasca (…) does not seem to be associated with the psychosocial problems that other drugs of abuse typically cause” (12).