Brazilian scientists have shown for the first time that the hallucinogenic drink ayahuasca can improve depressive symptoms.
Ayahuasca, or liana of the dead, is a herbal decoction used by the tribes of the Amazon for ritual purposes. Despite its hallucinogenic properties, this drink is legal in Brazil, which is often used by tourists. The active component of ayahuasca is the Banisteriopsis caapi liana, to which the leaves of other plants are added, in particular, chalipongs (Diplopterys cabrerana) and green psychotria (Psychotria viridis), containing dimethyltryptamine (DMT). DMT is a psychoactive alkaloid that normally dissolves in the gastrointestinal tract. However, the harmaline and harmine alkaloids in liana inhibit monoamine oxidase, which allows DMT to enter the brain. The effect of the substance lasts about six hours, the peak occurs approximately two hours after ingestion.
Ayahuasca tastes bad and is believed to aid in spiritual healing. In addition, the drink stimulates the cleansing of the body: for example, thanks to harmines, the broth has an anthelmintic effect. Before and during the intake of ayahuasca, shamans of the Amazon tribe abstain from sexual activity, and also observe a fast that excludes salty, fatty, spicy foods and alcohol - it is believed that the properties of these products are opposite to the drink. From a scientific point of view, such dietary restrictions prevent the growth of tyramine in the body, which requires monoxidases to oxidize. Ayahuasca is inhibited by alkaloids when taken, and without fasting this can lead to a sharp increase in adrenaline levels, panic attacks and death.
Dissociation scores after taking ayahuasca and placebo / Fernanda Palhano-Fontes et al., BioRxiv.org
Past work has shown that harmine and ayahuasca may have antidepressant properties in animals and humans, however, no placebo-controlled studies have been conducted so far. To fill the gap, researchers from the Federal University of Rio Grande do Norte and the University of São Paulo conducted a double-blind, randomized, placebo-controlled study in 35 patients with monopolar clinical depression aged 18–60 years. At the first stage, the subjects, to assess the disease, filled out the Dissociation Scale, after which they were in a quiet, calm environment for eight hours. During this time, participants received ayahuasca decoction containing 0.36 micrograms per kilogram of DMT for about four hours, or a placebo.
The results showed that after taking the placebo, some patients in the control group felt an improvement in symptoms compared to the experimental group. However, after a week, the effect ratio changed, and 64 percent of participants who took ayahuasca reported the beneficial effects of the decoction. By this time, in the placebo group, the increase was only 27 percent. It is noteworthy that the effect of ayahuasca was stronger than the effect of ketamine, a psychedelic with anesthetic properties, and the latter also surpassed placebo. According to the authors, despite the healing role of the decoction, the conclusions could also be influenced by placing the subjects in a comfortable environment. The positive dynamics was confirmed by the data of electroencephalography (EEG), electromyography (EMG) and other methods.
Details of the work are presented on the bioRxiv.org preprint server.
Denis Strigun
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