A psychedelic drink called ayahuasca, traditionally used for medicinal purposes among indigenous groups in the Amazon, may act as a fast-working and long-lasting anti-depressant, according to a preliminary study published in the journal Revista Brasileira de Psiquiatria (Brazilian Review of Psychiatry).

The main ingredient in ayahuasca is the vine of caapi plant, mixed with the leaves of other plants native to the Amazon region. The mixture is brewed and concentrated before being consumed. The drink is traditionally used in religious and healing ceremonies, and is known for inducing sensory hallucinations and altered emotional states. Chemical studies have found that it contains compounds that affect MAO-A regulation and other systems related to depression.

In a clinical study led by Flávia de L. Osório, of the Universidade de São Paulo, a team of psychiatric researchers examined the potential therapeutic effects of ayahuasca use in patients suffering from depression. Six volunteers diagnosed with Major Depressive Disorder and currently experiencing an acute depressive episode were given a single dose of the drink, and their symptoms were tracked for a period of 21 days.

On average, patients’ depression symptoms decreased significantly within the first 40 minutes of drinking ayahuasca, and had decreased even further a day later. Their levels of depression were still just as low by the end of the three-week follow-up period. The authors suggest that the most likely neurochemical explanation for the acute effects observed on depression symptoms are action of the chemical compounds found in ayahuasca on MAO-A and BDNF regulating systems. The longer lasting effects may have been caused by more complex interactions between groups of brain cells.

The authors of the study noted that this pattern of results was remarkable, because commercially available anti-depressant drugs require regular use for an average of two weeks before they begin to significantly reduce symptoms of depression. In this study, ayahuasca appeared to be effective after only one dose, worked rapidly, and remained effective over a course of weeks. The only significant side effect noted in this study was vomiting immediately after treatment, which was reported by half of those in the study.

The researchers concluded that the compounds found in ayahuasca have considerable potential for the development of new fast-acting and long-lasting treatments for depression. Although they are likely to be years away from development, if the authors of this study are right then patients suffering from depression may one day be able to thank traditional indigenous medical wisdom for more effective treatments.