A new study has uncovered a previously unknown link between the immune system and the fear response, and how psychedelics can play a role in suppressing it. The finding could improve the treatment of both mental, emotional and physical afflictions.
Research into the effects of psychedelics continues to make significant inroads in terms of the methods in which the mind-altering substances can improve our health.
A study last year showed that psilocybin was as effective as a commonly prescribed drug at alleviating depression, and actually helped improve overall quality of life over the pharmaceutical. A 2023 study showed that psychedelic substances were effective in improving the mental health symptoms and cognitive function of traumatized Special Operations Forces veterans. An even earlier study revealed the substances' role in improving long-term creative thinking.
Diving deeper into the role psychedelics have on our bodies, researchers at Mass General Brigham found that during chronic stress, our immune systems send inflammatory cells called monocytes to the amygdala, the brain region responsible for processing our emotions – especially fear, anxiety and aggression. Once there, these cells trigger the body's fear response as well as its inflammatory signaling.
Most interestingly, though, using mouse models, the team found that the psychedelics psilocybin and MDMA blocked the monocytes from collecting in the brain, thus hampering the immune system's ability to spark fear and create an inflammatory response.
"When chronic stress disrupts this signaling, it leads to a cascade involving brain-resident cells and immune cells that ultimately increases fear behavior," said research lead, Michael Wheeler. "What is fascinating is that psychedelic compounds can reverse this entire process."
The researchers also saw a similar response when looking at human brain cells and gene expression data collected from patients with major depressive disorder (MDD), showing that their findings could have implications in treating depression as well as fear-based disorders.
"Our study underscores how psychedelics can do more than just change perception; they can help dial down inflammation and reset brain-immune interactions," said Wheeler. "This could reshape how we think about treatment for inflammatory disorders and conditions like anxiety and depression."
The researchers say that uncovering this previously unseen link between the immune system's ability to trigger the fear response and its interruption by psychedelics warrants further research. They now plan to study how the long-term use of psychedelics can affect patients with inflammatory diseases or MDD. They'll accomplish this by analyzing the tissue samples of patients in a clinical trial in which psychedelics are being used to treat patients with depression.
"We’re not saying that psychedelics are a cure-all for inflammatory diseases or any other health condition," concludes Wheeler. "But we do see evidence that psychedelics have some tissue-specific benefits and that learning more about them could open up entirely new possibilities for treatments."
The research has been published in the journal Nature.
Sources: Mass General Brigham, Genomic Press via EurekAlert