Welcome back to The Drop In, DoubleBlind’s newsletter serving up news, culture, and independent journalism about psychedelics straight to your inbox.

Today’s lead story is about how ayahuasca can possibly heal the negative impacts of isolation brought on by the residual effects of the Covid pandemic and the over- reliance of social media. You can find that story immediately below (if you’re brave enough to read it and apply the info!)

If you keep scrolling, you’ll find stories about ketamine clinics in Beirut, the Horizon’s conference coming soon to NYC, and the need for “trip-free” psychedelics.

Whoop, there it is ☀️
Mary Carreón
Editor-in-Chief

The media reports we’re in a loneliness epidemic that’s persisted — and even worsened — since 2020, thanks to the COVID-19 pandemic and the greater cultural reliance on social media, dating apps, and the internet for socializing. According to the US Surgeon General’s advisory, approximately half of US adults report experiencing loneliness with some of the highest rates among young adults. In fact, young adults are almost twice as likely to report feeling loneliness than people 65 and older. Now, researchers are looking into the effects of long-term loneliness on the brain, and whether plant medicine, like ayahuasca, might be able to ameliorate negative effects. 

One of the most notable negative impacts of isolation on the brain is stress — it can cause physical damage to the brain, and even shrink neurons, making it harder for them to work efficiently. A small study published in February in the journal Translational Psychiatry tested whether ayahuasca could prevent neurons from reducing in size. Researchers at the Federal University of Rio Grande do Norte in Brazil, led by Luiz Roberto Fernandes Pereira, gave juvenile marmosets ayahuasca before and during nine weeks of isolation. The isolated monkeys that went untreated ended up with smaller neurons, a neurological impact researchers associate with chronic stress. The ones that drank ayahuasca maintained normal sized neurons, as if the isolation hadn't impacted them.

"These preliminary findings underscore ayahuasca's potential to mitigate stress-induced cortical atrophy and highlight its influence on neural plasticity," the authors wrote.

The sample size, however, was extremely small. Six common marmosets, a small monkey native to northeastern Brazil, were split into three groups of two: one that stayed with its family, one that was isolated, and one that was isolated and given ayahuasca. All six lived with their families for the first four weeks. Then the isolated and ayahuasca groups were pulled from their relatives and housed alone, cut off from the sight, sound and smell of other animals for nine weeks. Their cages came stocked with tree branches, wooden swings and a nest box. The ayahuasca group received three doses of the brew, delivered straight into the stomach through a tube. The first arrived three days before isolation began, the next two on days 25 and 50. The brew, prepared by a Brazilian temple from the Banisteriopsis caapi vine and Psychotria viridis leaves, carried its usual active ingredients, including DMT, which works on serotonin receptors in the brain.

When the team examined the brain tissue, the researchers looked at the size of neurons. Marmosets in the family group averaged a neuronal volume of 991.75 cubic micrometers. Isolated monkeys dropped to 457.55. The ayahuasca group landed at 773.70, which is close enough to the family group that the gap between them was considered statistically insignificant. 

The brain data echo what the same group found earlier in behavior. In prior work on these animals, the marmosets that drank the ayahuasca groomed themselves less compulsively, a marker of lower stress, and their cortisol levels were on par with those of the family-housed monkeys rather than the isolated ones.

While measures of overall cortical volume and neuronal density leaned in a promising direction, the trends could not definitively be confirmed because not enough data could be gathered with only two animals per group.

These findings are important given how pervasive depression is in our culture. It affects roughly 280 million people worldwide, and rates among adolescents have climbed, according to the study. The somatosensory cortex (the part of the brain that is most severely impacted by depression) loses about 30% of its dendritic spines during depressive states, the study says, gumming up the brain's signal processing. 

Of course, caveats abound. There were no female subjects, which is a glaring gap given that depression hits women harder, according to the study’s authors. The stressed monkeys got no placebo dose for comparison, a situation caused by pandemic logistics. And the whole thing ran on one batch of ayahuasca. "Findings on humans might differ," PsyPost noted in its coverage.

Still, the work adds a data point to a field that’s more based on enthusiasm and falls a bit short on primate anatomy. The authors pitch it as a foundation, a first look at what the brew might do to brain structure under stress.

"These preliminary findings underscore ayahuasca's potential to mitigate stress-induced cortical atrophy," the authors wrote in Translational Psychiatry, adding that the brew appears to shape neural plasticity.