Ayahuasca goes by many names: Daime, Vegetal, Hoasca, Kamarampi, Huni ... whatever you call it, this plant-based psychoactive decoction, which has been used by indigenous Amazonians for centuries to contact the spiritual world, has suddenly burst into global consciousness.
As a recent New Yorker article put it, ayahuasca is "the drug of choice for the age of kale".
The article, which positioned ayahuasca as a hipster trend in a tone of mockery mixed with mystification, nevertheless belies the growing interest of Western scientists and rich urbanites in its medicinal and therapeutic potential, which include antidepressant, anti-anxiety and anti-addiction elements.
Does the science support the hype? As part of a small cohort of Brazilian scientists undertaking the world's first clinical trials on ayahuasca and treatment-resistant major depressive disorder, I'm here to say: maybe, but it's too soon to tell.
Sacred plant, sacred medicine
First, some background, which is key to understanding how ayahuasca is perceived as both a sacred plant and medicine.
This idea is shared by indigenous groups, vegetalistas (healers that use plants to treat disease), and Brazilian religions such as the Santo Daime and the União do Vegetal, which blend Catholic, indigenous, and Afro-Brazilian beliefs.
In the indigenous context, ayahuasca is used to contact the supernatural world, the realm of the jungle spirits, who are called on to bring peace, happiness, and good health - or harm and disease.
During ayahuasca ceremonies, shamans invoke specific spirits either to heal their patients, or to harm their enemies. For them, ayahuasca is a powerful and dangerous plant used with great caution, and only by individuals who've undergone a prolonged initiation process that usually involves abstaining from sex and certain foods, along with periods of isolation in the jungle.
Ayahuasca is also used therapeutically by the rural, poor and mestizo, or mixed-race, populations of Amazonian nations, including Colombia, Peru, Brazil, and Ecuador, who have limited access to hospitals and physicians but extensive training in ayahuasca.
The spiritual is medical
The effects of ayahuasca start 30 to 40 minutes after oral intake, with a peak occurring one to two hours later. Most people describe a pleasant (although not always easy) experience, which may include changes in perception (mostly visual), deep introspection, revival of seemingly forgotten autobiographical memories, and mood boost. The trip lasts four to six hours.
A limited number of studies have suggested that those psychoactive effects could play a therapeutic role for humans.
Ayahuasca is made by combining the leaves of Psychotria viridis or Diplopterys cabrerana (which contain the hallucinogen DMT), with the jungle vine Banisteriopsis caapi, which is rich in a group of alkaloids called beta-carbolines (harmine, tetrahydroharmine, and harmaline).
Observational studies have also indicated that long-term members of Brazilian ayahuasca religions have apparently recovered from depression, anxiety, and drug dependence (especially alcohol and cocaine).
Recent preliminary, open-label studies, or non placebo-controlled trials, on patients diagnosed with treatment-resistant major depressive disorder have been promising.
These studies, led by Jaime Hallak from the University of São Paulo medical school in Ribeirão Preto, where I work, and by Draulio de Araujo, from the Federal University of Rio Grande do Norte, in Natal, showed that a single ayahuasca dose was associated with significant, fast-acting, and enduring antidepressant and anti-anxiety effects.
These positive results started in the first hours after ayahuasca intake and remained significant 21 days later.
Out of the jungle, into the cities
In the early 20th century, during the exploration of natural rubber, a small number of religious organisations that centred their sacred rituals on ayahuasca as a sacrament began to emerge in the Brazilian state of Acre. These groups blended Catholic beliefs with Amazonian shamanism, European esoteric philosophies, and Afro-Brazilian tradition.
In the late 1970s and early 1980s, these religions organisations began to expand from the North of Brazil to other Brazilian capitals. In the early 1990s, some - in particular the União do Vegetal and Santo Daime - started to create groups in Europe and in the US. Today they are among the main forces collaborating to extend ayahuasca's use beyond the Amazon.
In recent years, healers called vegetalistas or maestros ("those who know") have started to practice rituals in big cities, including Bogota, New York, and other urban centres. In these places, their patients are more likely to be wealthy white people seeking healing from anxiety, mood disorders, drug dependence and other mental health issues.
As more Westerners come to South American countries for healing ayahuasca trips and more healers travel to the US and Europe to perform their rituals, the idea that ayahuasca has powerful therapeutic potential has spread worldwide.
Indeed, in the aforementioned New Yorker article, one American researcher is quoted as saying that "on any given night in Manhattan, there are a hundred ayahuasca 'circles' going on."
This interest is also illustrated by a recent conference held in Acre and organised by the International Center for Ethnobotanical Education, Research & Service, which put together more than 700 participants from around the word, including dozens of indigenous participants.
In the past year or so, many other major international news outlets have covered ayahausca, including the New York Times, Vice and Nature. Their pieces tend to portray the plant as a potential "cure" for addiction and depression.
Too early to tell
Media hype and promising medical results aside, I must highlight critical limitations of the few studies that have inspired this enthusiasm for ayahuasca.
First, the small sample size (only 17 individuals) and their non-controlled (no placebo) design makes the results unsound from a scientific perspective. Indeed, the placebo effect can be very significant in antidepressant studies.
Therefore, it is not currently possible to conclude that the observed effects were really caused by ayahuasca, or that ayahuasca can "cure" depression.
My Brazilian colleagues, supervisors and I are now trying to replicate these observations in the lab with improved methodology. A bigger study assessing the antidepressant potentials of ayahuasca with 80 patients, using a double-blind, placebo-controlled design, is currently underway. And we at the Ribeirão Preto Medical School are in the middle of a research project on the impacts of ayahuasca treatment on socially anxious individuals.
Ayahuasca has captured the imagination of scientists and hipsters alike. By helping us find the sacred within us, its psychoactive power seems to hold therapeutic potential as an alternative way to address common disorders that modern medicine has thus far found difficult to treat.
So is this sacred Amazonian medicine a potential treatment for everything from anxiety disorders to drug dependence, as both healers and patients avow? We'll have to wait and see what the science says.