Cortisol is a hormone that most people associate with stress. The adrenal gland produces cortisol, and the hormone helps in different body functions and systems, including stress responses, the immune system, nervous system and circulatory system, according to an article on a National Institutes of Health website. It also helps metabolize fats, protein and carbohydrates.
Cortisol has many functions, but it also affects overall mental health. When a person gets stressed, the body reacts in certain ways. Different hormones are secreted, including cortisol, according to the textbook “Abnormal Psychology: An Integrative Approach.”
However, if cortisol secretions get out of control over time, the hormone can kill nerve cells in a certain area of the brain called the hippocampus. Physical and mental functioning can be harmed in response to chronic stress. This long-term stress and cortisol secretions can lead to dementia and the inability to fight off infectious disease.
https://www.empowher.com/mental-health/content/cortisol-and-link-mental-health