Medical News Today: How a hallucinogenic brew makes the brain live in a dream

Ayahuasca is a psychoactive brew that people from the Amazonian regions traditionally use as a spiritual medicine. This brew reportedly induces strong hallucinations, but what, exactly, does it do to the brain?

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Researchers have discovered evidence of ayahuasca — also known as “yagé” — in use by shamans, dating back at least 1,000 years.

Traditionally, this hallucinogenic brew is meant to help people heal spiritually and physically, though, nowadays, some people use it for recreational purposes, more often than not, illicitly.

Ayahuasca is the result of brewing a mix of the ayahuasca vine (Banisteriopsis caapi) and chacruna shrub (Psychotria viridis), which contains dimethyltryptamine (DMT), the main psychoactive ingredient of this drink.

DMT is a potent hallucinogenic substance that leads to profound states of altered consciousness. Some studies have even suggested that using DMT can make people feel like they are having a near-death experience.

In an interview for the BBC, one person who took a controlled amount of DMT as part of a scientific study describes her experience as akin to stepping into a different form of reality.

“I felt like I arrived in some consciousness soup, which seemed like a different realm to the one I ordinarily inhabit — even in dreams. It just seemed like everything was rotating and swirling and spiraling. It didn’t seem like there were normal space-time proportions going on,” the interviewee said.

Psychoactive drug impacts brainwaves

A team of researchers from Imperial College London in the United Kingdom wanted to find out more about what exactly happens in the brain when it accesses such a deep state of altered consciousness.

To do so, the investigators recruited 13 volunteers — of whom six were female and seven male, with a mean age of 34.4 — who agreed to take controlled doses of DMT while the study authors recorded electrical activity in their brains using electroencephalograms (EEGs). The researchers report their findings in a study paper featuring in the journal Scientific Reports.

By looking at the EEG scans, the team found that DMT had a significant impact on the brain’s electrical activity during a waking state. More specifically, they saw that the participants who had received DMT injections showed a clear drop in alpha waves, the brainwaves that are usually most present when we are awake and relaxed.

On top of this, the researchers noticed an increase in theta waves — the brain waves scientists associate with dreaming — if only for a short time.

Moreover, the team saw that the activity in the brains of people who had received DMT had become more chaotic, in a manner resembling what happens in the brain during general anesthesia or states of deep sleep.

“The changes in brain activity that accompany DMT are slightly different from what we see with other psychedelics, such as psilocybin or LSD, where we see mainly only reductions in brainwaves,” explains the study’s lead author, Christopher Timmermann.

Yet, he adds, “Here, we saw an emergent rhythm that was present during the most intense part of the experience, suggesting an emerging order amidst the otherwise chaotic patterns of brain activity. From the altered brainwaves and participants’ reports, it’s clear these people are completely immersed in their experience — it’s like daydreaming only far more vivid and immersive, it’s like dreaming but with your eyes open.”

DMT research may reveal brain secrets

While the study has offered further insights into what deep states of altered consciousness look like in the brain, it remains unclear whether the psychoactive substance the researchers used in the experiments brings any clinical benefits.

Past research that Medical News Today reported on has suggested that DMT may help reduce symptoms of treatment resistant depression. However, Timmermann and colleagues have not yet found any evidence regarding the drug’s medicinal potential, though they say that this is something they want to investigate more extensively in the future.

Commenting on the findings of the current study, co-author Robin Carhart-Harris, Ph.D., notes that “DMT is a particularly intriguing psychedelic. The visual vividness and depth of immersion produced by high doses of the substance seems to be on a scale above what is reported with more widely studied psychedelics, such as psilocybin or ‘magic mushrooms.'”

“It’s hard to capture and communicate what it is like for people experiencing DMT, but likening it to dreaming while awake or a near-death experience is useful. Our sense i[s] that research with DMT may yield important insights into the relationship between brain activity and consciousness and this small study is a first step along that road.”

Robin Carhart-Harris, Ph.D.