Mass General Brigham researchers found that interactions between immune and brain cells drive fear responses, but treatment with psychedelics like MDMA and psilocybin may reverse these effects.

The new study suggests that fear and the immune system are connected in previously unknown ways. The researchers found that the immune system can influence stress and fear behaviors by changing how brain cells communicate.

The investigators further showed that psychedelic treatments could target these neuroimmune interactions and reduce stress-induced fear in preclinical models and found similar results in human tissue samples. Results are published in Nature.