LSD has long been known to enhance our connection to other people, causing an increase in empathy, compassion, and trust. Because of the difficulty in pinning down the neurobiological mechanism for these changes,researchers have been unable to effectively utilize them for medical treatment of disorders that impact social behavior, like anxiety and some instances of autism spectrum disorder. A recent study, however, may have uncovered the mystery of LSD’s marked effects on social behavior.
The study, which examined the effects of LSD on mice, could shed light on how it may have a prosocial effect on humans. “[The results of the study] were surprising,” says Dr. Gabriella Gobb, head of the Neurobiological Psychiatry Unit at McGill University in Montreal. “We spent about 2 years in testing animals with low doses of LSD. We did all kinds of behavioral tests, and finally, we realized that the strongest effect was on social behavior.”
The medial prefrontal cortex (mPFC) is the area of the brain associated with social behavior and social response inhibition and control. Researchers were able to isolate three components of the mPFC that interact with LSD: the mTORC1 protein complex and the receptors 5-HT2A and AMPA.
Gobbi explains how the findings could translate to human medicine. “In our research recently published on PNAS, we found that low doses of LSD enhanced the social behavior in mice paralleled by an enhancement of AMPA synapses and the mTOR protein,” she explains. “We know that these behavioral tests in mice–already validated for other prosocial substances, like oxytocin–correspond to increased empathy in humans. Moreover, in humans with deficits in sociability, like autism spectrum disorders, there is an impairment of the AMPA and mTOR.”
In the study, researchers injected one group of mice with a low dose of LSD (5 to 20 μg/kg), and another group with a placebo. Some of the mice given LSD were also given drugs that block the 5-HT2A and AMPA receptors. Both groups were then placed in a cage for 10 minutes to familiarize themselves with their surroundings.
After 10 minutes, an unfamiliar mouse was placed in the same cage, and allowed to freely interact with the other mice. The mice treated with LSD alone showed a preference for interacting with the unfamiliar mouse more than mice treated with other drugs or those given a placebo did. These mice also showed a preference for spending time with the unfamiliar mouse over spending time in an empty cage.
Translating these results to human medicine, though, for the treatment of disorders like anxiety or autism spectrum disorders, is likely to take time. “First, these substances should go in Schedule II in order to be used in medicine. Second, we have to demonstrate that LSD is safe and efficacious in diseases like social anxiety or autism by doing clinical trials in hundreds of people,” says Gobbi. “Clinical trials in autism are very complex since social behavior and empathy in humans are difficult to be evaluated and very subjective.”
Gobbi believes there’s still more about the brain that psychedelics can teach us, and that their worth goes beyond opening new treatment avenues. “I am fascinated by the study of psychedelics not only from a therapeutic point of view but because they help us to understand a lot of brain functions still unknown, like the consciousness, the transcendental thinking, the mysticism and the empathy toward humanity,” she says. “All these functions are still a mystery for neuroscience.”
Image: Nicki Adams