Ayahuasca is a psychedelic brew used in shamanic healing rituals and initiation rites throughout the Amazon. It is made by boiling the leaves of a plant called chacruna (Psychotria viridis) with the ayahuasca vine (Banisteriospsis caapi). The former contains a potent psychedelic compound called N,N-Dimethyltryptamine (DMT), which, interestingly, is found in nearly all the plants and animals we eat. However, upon arrival in the gut it is destroyed by an enzyme called monoamine oxidase, so it doesn’t reach the brain and produce its hallucinogenic effects.
That’s where the B. caapi comes in: It contains compounds called monoamine oxidase inhibitors that block these enzymes and ensure the DMT reaches the brain intact, resulting in an intense psychedelic trip, typically lasting four to six hours.
However, while the brew may be safe from a physical perspective, Riba says that without the correct preparation, taking an ayahuasca trip can be psychologically damaging. “Some people may experience anxiety due to the intense and unusual nature of the experience. This is most often the case with travelers to the Amazon who take ayahuasca with people they don’t know or trust in an unfamiliar setting.”
Indeed, while members of indigenous Amazonian communities are primed from birth to be able to deal with the visions encountered during their ayahuasca trips, Western backpackers can often be overwhelmed by their psychedelic experiences.
As scary as it sounds, the mind-expanding trip generated by ayahuasca has been found to have therapeutic value. “People who have taken ayahuasca report having been confronted with painful personal issues. They claim to have gained new insights into these issues, helping them to come to terms with them,” says Riba. “We have even seen people manage to overcome heavy cocaine and opiate addictions after a series of ayahuasca sessions.”
Amazingly, one Beckley/Sant Pau study found that taking ayahuasca produced an anti-depressant effect in individuals who had failed to respond to any other treatment for their depression. Even more remarkable was the fact that this improvement in symptoms was noticed almost immediately after the ayahuasca session and persisted for several weeks – a period Riba calls “the after-glow”, and which he says offers a “vital window of opportunity for psychotherapy,” as patients tend to be much more open and receptive at this time.
Harnessing the ayahuasca after-glow may, therefore, lead to faster, longer-lasting treatments than those currently used for depression, such as SSRIs. Uncovering the neurological mechanisms behind this after-glow effect is the next big challenge for ayahuasca researchers, and several pieces of the puzzle have already been discovered.
However, brain imaging studies have shown that under the effects of psychedelics like DMT, LSD and psilocybin, “the repressive control of the default mode network is lessened, so there’s more whole-brain connectivity and perception becomes much richer. It resets the psyche, and people often find that they can break free from their compulsive patterns of thought and behavior.”
The reduction in the size of the PCC may well mediate this effect in ayahuasca drinkers, although it is unlikely to be the only factor. For instance, a separate study revealed how a type of brainwave called alpha waves is markedly reduced during an ayahuasca trip.
Given that much of the activity of the default mode network is coordinated using alpha waves, it is perhaps unsurprising that this reduction was also correlated with an increase in mindfulness. Even more intriguing is the fact that a similar effect has been found in the brain during meditation, suggesting that both of these ancient healing practices may activate the same neurological circuits in order to bring about their therapeutic effects.
Overall, Riba claims that “ayahuasca’s three main areas of potential application are the treatment of addiction, depression and psychological trauma.” Yet as Feilding points out, “we are at the foothills of understanding how these compounds work,” and much more important research is needed if we are to unlock the secrets of this ancient hallucinogen.