A new study published in Nature has shown that fear and the immune system are linked in previously unknown ways, with the immune system potentially influencing stress and fear behaviors.
The study used a mouse model to study communications between immune cells and brain cells, called neuroimmune interactions. The investigators found that increased crosstalk between these cells in the amygdala led to increased fear behaviors, greater inflammatory signaling, and activation of fear-promoting neurons. During chronic stress, the investigators found that inflammatory immune cells from other parts of the body tended to migrate to the brain. Treating the chronically stressed mice with psilocybin and MDMA prevented the inflammatory immune cells from accumulating in the brain and lowered fear behaviors. Previous research has linked immune signaling to the development of psychiatric diseases such as depression, and the researchers further found similar signals between immune cells and brain cells during stress in human patients with major depressive disorder.
The authors noted that their results highlight the fact that psychedelics have potential to lower inflammation and regulate immune-brain interactions in a healthy way. This study also suggests a mechanism by which psychedelics might treat inflammatory disorders and mental health disorders such as depression and anxiety. In particular, psychedelics seems to have tissue-specific benefits that could open up new possibilities for the treatment of inflammation, fear, anxiety, and depression.
Future research will include studies on the treatment of people with inflammatory disorders or depression with psychedelics and the monitoring of tissue samples to see if immune-brain interactions are affected. Stress, fear, anxiety, and inflammation can have negative impacts on the heart, and chronic stress in particular can lead to heart disease through inflammation that contributes to the buildup of plaque in the arteries. Stress can also negatively impact regulation of blood sugar, blood pressure, and cholesterol. Addressing chronic stress, through psychedelics or other mechanisms, has potential to positively impact many aspects of physical and mental health.
Sources: Nature, Science Daily
