Tourists are increasingly trying ayahuasca during holidays to countries such as Brazil and Peru, where the psychedelic drug is legal. Now the world’s first randomized clinical trial of ayahuasca for treating depression has found that it can rapidly improve mood.
The trial, which took place in Brazil, involved administering a single dose to 14 people with treatment-resistant depression, while 15 people with the same condition received a placebo drink.
A week later, those were given ayahuasca showed dramatic improvements, with their mood shifting from severe to mild on a standard scale of depression. “The main evidence is that the antidepressant effect of ayahuasca is superior to the placebo effect,” says Dráulio de Araújo of the Brain Institute at the Federal University of Rio Grande do Norte in Natal, who led the trial.
Shamans traditionally prepare the bitter, deep brown brew of ayahuasca-using two plants native to South America. The first, Psychotria Viridis, is packed with the mind-altering compound dimethyltryptamine (DMT). The second, the ayahuasca vine (Banisteriopsis caapi), contains substances that stop DMT from being broken down before it crosses the gut and reaches the brain.
A day before their dose, the participants filled in standard questionnaires to rate their depression. The next day, they spent 8 hours in a quiet, supervised environment, where they received either the placebo or the potion, which produces hallucinogenic effects for around 4 hours. They then repeated filling in the questionnaires one, two and seven days later.
“The findings suggest a rapid antidepressant benefit for ayahuasca, at least for the short term,” says David Mischoulon of Massachusetts General Hospital in Boston. “But we need studies that follow patients for longer periods to see whether these effects are sustained.”
If the finding holds up in longer studies, it could provide a valuable new tool for helping people with treatment-resistant depression. An estimated 350 million people worldwide experience depression, and between a third to a half of them don’t improve when given standard antidepressants.
Ayahuasca isn’t the only psychedelic drug being investigated as a potential treatment for depression. Researchers have also seen some benefits with ketamine and psilocybin, extracted from magic mushrooms, although psilocybin is yet to be tested against a placebo.