Sacred jungle medicine tested for hard-to-treat depression

A plant-based beverage consumed in spiritual ceremonies is associated with the relief of depressive symptoms in patients who do not respond well to conventional treatments, according to a small trial. The results, however, should be taken with caution until more work is done, experts say.

Known as ayahuasca, the brew, made out of a mixture of psychoactive plants native to the Amazon rainforest, has generated media hype over the past two years due to its alleged therapeutic effects, even though it has not been approved by the FDA.

The only evidence researchers had about its efficacy came from weak scientific studies and testimonies of ceremony participants who would often indicate that the concoction — costing around $100 in Peru and Brazil, the only two countries where ayahuasca is considered legal — helped them overcome episodes of major depression.

The next step was to test whether patients were really responding to ayahuasca, according to neuroscientist Dráulio de Araújo at the Federal University of Rio Grande do Norte in Natal, Brazil. So his team decided to give half of study participants a sham drug, also known as a placebo, that mimicked the brownish color and the bitter and sour taste of the hallucinogenic drink (even some of its side effects, like nausea and vomiting, too.)

His results provide a faint hint that a single dose of the plant beverage reduces depression symptoms more rapidly than other antidepressants available in the market. Still, the paper, which was uploaded to an online repository called bioRxiv in January, has been rejected by 12 different journals so far due to what de Araújo calls “editorial decisions.” Psychiatrist Charles Grob, who has previously studied and consumed the Amazonian plant beverage but was not part of this research, shares de Araújo’s frustration. “I think ayahuasca is so off-the-radar of the mainstream [journals], but it certainly merits publication,” he says.

James Stone, a psychiatrist at King’s College London who has previously tested novel drug treatments for psychosis and depression, says the findings are more robust than what has been published to date. Still, a lot more work needs to be done. “There is a need for data on long-term effects and for the study to be repeated in a larger sample,” he says.

De Araújo and his team recruited 29 patients who had taken at least two antidepressant drugs in the past without signs of improvement. Each person was randomly treated with ayahuasca or with a fake brew during a single session. To ensure further blinding, not even the psychiatrists evaluating the patients knew who had received the real thing.

The findings reveal that, compared to the people who only received a placebo, the ayahuasca group had a more pronounced and sustained recovery seven days after dosing.

“The change in depressive symptoms is dramatic,” says Stone, who was not involved in the trial. In less than a week, patients who had been experiencing pervasive low mood, sluggishness, impaired sleep, reduced appetite, guilt or pessimistic thoughts for years described their symptoms, on average, as “much less intense.” They still presented slight signs of depression, though.

Despite the promising results, the team struggled with evaluating patients’ response weeks and months after dosing. “We had a lot of drop-offs, so many patients just did not come back [after seven days],” de Araújo admits. The lack of data is troubling, according to Stone, since depression is a long-term disease.

But Grob, who leads one of the most active groups for this kind of psychoactive drug research at Harbor-UCLA Medical Center, does not feel discouraged. “These guys have just scratched the surface,” he says. “Their work really sets the table for a more comprehensive study.”