Psychological stress is associated with greater risk for depression, heart disease and infectious diseases. Until now, it has not been clear exactly how stress influences disease and health. Chronic psychological stress is associated with the body losing its ability to regulate the inflammatory response. Inflammation is partly regulated by the hormone cortisol and when cortisol is not allowed to serve this function, inflammation can get out of control. Prolonged stress alters the effectiveness of cortisol to regulate the inflammatory response because it decreases tissue sensitivity to the hormone. Specifically, immune cells become insensitive to cortisol’s regulatory effect. In turn, runaway inflammation is thought to promote the development and progression of many diseases.
Proceedings of the National Academy of Sciences, April 2012