Question: What is the relationship between depression and the immune system?
Answer: Depression really has profound effects on the immune system. Depression can cause increases in a variety of stress hormones such as cortisol and adrenaline and various other inflammatory substance such as interleukin-6.
Increases in all of these hormones and other substances can cause significant decrease in the body's ability to repair itself and for a variety of organ systems to function well. This may lead to inflammatory conditions such as arthritis. It can cause osteoporosis. It may lead to various infections because of a breakdown in normal immune system functioning. And it can also cause or worsen cancers.
So diagnosing and treating depression not only helps a person to feel and function better, but it may also preserve their long-term physical health.