Scientists have discovered that psychedelic drugs may improve mental health by dampening inflammation in the brain, according to a groundbreaking new study published in the journal Nature.
Previous research has shown psychedelic drugs to be potential tools in combating mental health issues, but the understanding behind why these drugs produce such results remains unclear.
In the study, researchers from Harvard Medical School identified a potential mechanism explaining why drugs like psilocybin and MDMA show promise in treating conditions such as depression, anxiety and PTSD. Their findings suggest that psychedelics’ therapeutic effects may stem partly from their ability to reduce brain inflammation, which is elevated in many mental health disorders.
The team examined how psychedelics affect brain cells called astrocytes in the amygdala, a brain region involved in processing fear and anxiety. They discovered that these astrocytes influence inflammation levels through a protein called epidermal growth factor receptor (EGFR).
In their experiments, mice experiencing chronic stress showed reduced activity in a gene that produces EGFR, which normally helps regulate inflammation. Wheeler suggests this relationship may have evolved to prepare the body for possible injury after experiencing fearful situations.
To study the stress response, researchers restrained three mice in tubes for six hours daily over 18 days, inducing anxiety-like behaviour. Genetic analysis revealed that astrocytes in the animals’ amygdala had reduced EGFR activity, which is associated with increased inflammation.
In a follow-up experiment, researchers deactivated the EGFR gene in nine mice and subjected them to stressful conditions, including electric shocks paired with sounds and flashing lights. When later exposed to just the sounds and lights, these mice spent about 15 per cent more time frozen in fear compared to control mice with intact genes.
The most striking results came when researchers treated mice with psychedelic drugs after subjecting them to the same chronic stress protocol. Half received psilocybin, the active compound in magic mushrooms, and half received MDMA. Five mice were used as the control group and given no psychedelics.
Compared with untreated mice, those given psychedelics showed about 75 per cent fewer inflammatory immune cells in the protective tissues around their brains, similar to levels in unstressed animals. When exposed to fearful stimuli, the treated mice also exhibited significantly less fear behaviour, freezing for durations comparable to mice that had never experienced stress.
Albert Garcia-Romeu at Johns Hopkins University, who was not involved in the study, called the findings potentially groundbreaking. “We still don’t really understand how psychedelics produce these very long-lasting [mental health] effects, but this may give us a really compelling window into one of the main mechanisms.”
The research could have implications beyond psychiatry, Garcia-Romeu added. “This opens up a whole new realm of possibility for how we might be able to use psychedelic treatment for non-psychiatric conditions associated with inflammation.”
