Psychosocial stress promotes the release of IL-6, potentially driving the development of depression.
Psychosocial stress, such as that experienced with divorce, discrimination, trauma, or the death of a child, can have profound effects on the human body. For example, evidence indicates that stress alters the immune system, driving inflammatory processes and impairing antiviral responses. Findings from a 2013 study suggest that psychosocial stress promotes the release of interleukin 6 (IL-6), potentially driving the development of depression.
IL-6 is a pro-inflammatory cytokine that plays an important role as a mediator of fever and the body’s immune response. It is produced by almost all immune cells and is induced in the context of infection, autoimmunity, or cancer. Many physiological processes are influenced by IL-6, including glucose metabolism, blood cell production, neuroendocrine regulation, and fatigue, among others. IL-6 levels are often elevated in people who have depression.
The investigators conducted their study using mice that had undergone radiation to destroy their bone marrow, compromising their immune function. Then they transplanted bone marrow from mice that exhibited either high or low levels of IL-6 levels in response to stress into the immune-compromised animals. Then they exposed the animals to a social stressor.
They found that mice that received transplants from those that exhibited high IL-6 levels in response to stress demonstrated more depression-like behaviors than the mice that received transplants from those that exhibited low IL-6 levels. These findings suggest that IL-6 promotes a pro-inflammatory state that promotes depression-like symptoms in response to psychosocial stress. Identifying therapeutic strategies that inhibit IL-6 may benefit people who are vulnerable to the effects of psychosocial stress.
Interestingly, hyperthermia, such as that experienced with sauna use or hot baths, has been shown to reduce IL-6 levels. Learn more about the beneficial effects of sauna use in our overview article.