For centuries, Amazonian shamans have been brewing ayahuasca, a hallucinogenic plant-based tea, for use in traditional healing ceremonies.
Now, the substance has caught the attention of not only the American tourists and spiritual seekers traveling to South America to participate ayahuasca retreats, but also medical researchers, who are investigating ayahuasca (also known as the "spirit vine") as a treatment for mental health problems such as depression and post-traumatic stress disorder.
This week, the results of the first clinical trial investigating ayahuasca as a treatment for depression were published in the Brazilian Review of Psychiatry. Its publication marks a promising early step toward clinical use of the psychotropic substance as a treatment for depression and other mental health problems.
For the small study, neuroscientists at the University of Sao Paulo in Brazil gave ayahuasca to volunteers who had been diagnosed with depression that proved resistant to at least one type of antidepressant. The researchers observed reduced depression in all participants within two to three hours of ingesting the substance, and also after a three-week follow-up.
The preliminary study had a very small sample size of only six participants. The study's conclusions are further limited by the absence of a placebo group, but they do suggest the plant holds promise as a fast-acting treatment for depression.
"This is an area that really does merit further work and serious consideration," Dr. Brian Anderson, a psychiatrist at the University of California, San Francisco, who has also conducted medical anthropological work on ayahuasca, told The Huffington Post. "There's a need for effective treatments that can work in the short term. A lot of our current depression treatments take weeks to use, when we think about pills or psychotherapies."
So how does the brew provide both immediate and lingering relief from depressive symptoms? Like pharmaceutical antidepressants, ayahuasca seems to alter concentrations of the mood-boosting neurotransmitter serotonin in the brain.
“It is possible that ayahuasca and other serotonergic psychedelic drugs, such as psilocybin, may be useful as antidepressants for particular subsets of patients in the future,” King's College psychiatrist James Stone, who has studied the effects of psychedelic drugs on the brain, told Nature.
Another possible way ayahuasca may alleviate feelings of depression is through its active ingredient, the psychoactive chemical DMT (dimethyltryptamine), which is known to induce spiritual experiences and revelations.
Larger, placebo-controlled trials using ayahuasca for depression are already underway. Another group of Brazilian researchers are about halfway through a double-blind trial that will be conducted on 80 participants, Nature reported.
Ayahuasca joins other psychedelics including MDMA, LSD and psilocybin (the active ingredient in magic mushrooms) as substances scientists are investigating as treatments for depression. However, even in controlled settings, the use of ayahuasca and other psychedelics isn't without risk. There are some case reports of people experiencing psychological distress after using ayahuasca, and it's possible in some cases the hallucinogen could worsen symptoms of depression.
Still, the research offers reason for optimism.
"This study is helpful because it's actually documenting, in a structured hospital setting, that this is being done safely," Anderson said.