The first clinical study conducted on ayahuasca’s potential therapeutic benefits suggests that it could have a long-lasting and positive effect on depression. The researchers are now conducting larger studies that they hope will support these initial findings.
The brew has been studied by anthropologists, social scientists and theologians, but clinical research on ayahuasca has been limited to observation of its effects in mice and rats, and in healthy human volunteers3, including brain-studies4 and retrospective surveys of past use5.
For the latest study, researchers led by Jaime Hallak, a neuroscientist at the University of São Paulo, Brazil, gave one mild dose of ayahuasca to six volunteers who had been diagnosed with mild to severe depression that was unresponsive to at least one conventional antidepressant drug. None had drunk ayahuasca before.
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.
“It is a proof of concept of what so many ritual ayahuasca users already know: ayahuasca can help one feel extra well, not just during the experience, but for up to days or weeks after,” says Brian Anderson, a psychiatrist at the University of California, San Francisco, who was not involved in the study but has published papers on the drink’s potential6. “The relationship between ayahuasca’s psychedelic effects and its therapeutic effects needs to be empirically studied,” he says.