Psychedelics Can Reverse Brain-Immune Interactions That Elevate Fear, Study Finds

Recent research from Mass General Brigham has shed new light on how immune and neural interactions contribute to fear and stress responses. The study reveals that immune cells and brain cells communicate in ways previously unrecognized, influencing behaviors related to fear. Researchers found that treatments with psychedelics such as MDMA and psilocybin can modulate these neuroimmune interactions, potentially reducing fear and inflammation.

The findings demonstrate that immune signaling can affect stress-related behavior by altering communication within the brain, particularly in the amygdala, the region responsible for processing fear. In animal models subjected to chronic stress, enhanced interaction between immune and brain cells heightened fear responses, increased inflammatory signals, and activated neurons that promote fear. Notably, immune cells called monocytes migrated into brain structures during stress, and manipulating these cells affected fear behaviors.

Importantly, psychedelic treatments prevented monocyte infiltration and lowered fear in stressed animals. These effects were also observed in human tissue samples and gene expression data from patients with major depressive disorder (MDD), suggesting similar neuroimmune mechanisms could be involved in human neuropsychiatric conditions.

Lead researcher Dr. Michael Wheeler emphasized that psychedelics may extend beyond altering perception to helping reset inflammation and brain-immune communication. The research opens avenues for new treatments targeting immune system involvement in anxiety, depression, and inflammatory diseases.

Future work aims to explore the long-term effects of psychedelic therapy on patients with depression and inflammatory disorders. Dr. Wheeler noted ongoing collaborations on clinical trials involving psychedelic treatments, emphasizing the potential for these substances to offer tissue-specific benefits. However, he clarified that psychedelics are not a universal cure but present promising possibilities for therapeutic development.

This groundbreaking study highlights how enhancing our understanding of neuroimmune interactions could revolutionize approaches to mental health and inflammatory conditions.

(Source: https://medicalxpress.com/news/2025-04-psychedelics-reverse-neuroimmune-interactions-boost.html)