A new clinical study out of the University of Sao Paulo in Brazil has tested the effects of the ayahuasca healing brew on six volunteers suffering from serious depression. The treatment demonstrated that a mild dose of ayahuasca was able to alleviate symptoms of depression from within three hours to up to three weeks.
Neuroscientist Jaime Hallak and a group of researchers at the University examined if the psychotropic brew mixture of the vine Banisteriopsis caapi and the leaves of the shrub Psychotria viridis could treat depression. The World Health Organization estimates that about 350 million people suffer from depression worldwide, and global usage of antidepressants is rising.
The Nature journal of science reported on the details of the experiment:
After their drink, the participants sat in a quiet, dimly lit room. Physicians used standard clinical questionnaires to track their depression symptoms. Improvements were seen in two or three hours (though the psychedelic effects of an oral dose take around five hours to wear off) — a rapid effect, as conventional antidepressants can take weeks to work. The benefits, which were statistically significant, continued to hold up in assessments over the next three weeks. Three of the participants vomited, a common side effect of ayahuasca, but otherwise the procedure was well tolerated, Hallak says. 
For years, South American medicinal plants have been used by indigenous people for spiritual and physical healing. Now the ayahuasca brew has become more available to Westerners and the people seeking out new therapies to lessen the burden of depression and other mental health issues. Ayahuasca ceremonies in Costa Rica and Peru are quite common, yet finding an authentic experience such as authentic council gatherings with the Secoya Elders, whose cultural tradition of healing with this medicine extends back thousands of years.
With increasing interest in the possibilities of this medicine as a clinical treatment for mental health issues, especially depression, scientific research continues into the mysteries of these tropical plants. In Brazil, for example, using neuroimaging technology, Hallak’s team made the following discoveries:
Neuroimaging of the brains of the participants eight hours after ingesting ayahuasca revealed increased blood flow in areas of the brain whose diminished activation is usually associated with depression and increased activation is commonly associated with antidepressant effects.
The researchers attribute the antidepressant effects of ayahuasca to DMT, the principal psychoactive ingredient in ayahuasca, as it is an activator of serotonin receptors in the central and peripheral nervous systems. 
Hallak’s co-author of the research, Draulio d Araujo, a neuroscientist at the Federal University of Rio Grande do Norte in Natal, Brazil, has already begun a larger randomized, double-blind, placebo-controlled study of the effect ayahuasca has on depression.
Scientific studies help to validate the effectiveness of Ayahuasca as a proper medicine, but the reasons that it works so well at triggering positive personal transformation may always be impossible to rationally understand. This medicine is more than a chemical that alters brain chemistry, it’s a holistic body, mind and spiritual experience that brings one into contact with the spirit of Ayahuasca, offering a genuine and very direct spiritual experience.
In his book, Rainforest Medicine: Preserving Indigenous Science in the Upper Amazon, author Jonathon Miller-Weisberger likens the transformative experiences of Ayahuasca to a celestial university, calling this an ancient science, and “the original education system of the inhabitants of the Amazon region.” He explains further that, “when adhered to correctly, this system’s curriculum provides a complete development of all the aspects of the self – intellectual, physical, and spiritual.