Many studies have found that stress can affect inflammation in Major Depressive Disorder. It has also been found that anger can induce cortisol while fear can cytokine while decreasing cortisol. This suggests that anger may trigger adaptive and mobilize energy while fear also promotes withdrawal. A lack of anger may be a cause for depression correlated inflammation. Stress related emotions may have an effect on monoamine oxidase activity and activate the primary microglia of the immune cell.