Question: What are some of the diseases/conditions that can be affected by stress?
Answer: So one of the remarkable things about the link between stress and illness is that stress is a risk factor for a wide range of illnesses that are themselves interrelated. So the classic illness that stress is a huge risk factor for is major depression. We've come to realize over the last few years that major depression is also a risk factor for heart disease, for diabetes, and probably for dementia, maybe for cancer. Now these are the primary killers of the modern world. Stress is also a risk factor for those physical illnesses.
Research is beginning to suggest that the reason that these links exist is because, when we're under psychological stress, we activate systems in our body that -- although useful for coping with immediate dangers -- over time damage the tissues of our body. So that they stress systems cause your blood pressure to rise, they cause your body to be less efficient at handling blood sugar, so that you're at a risk for diabetes. Stress activates inflammatory parts of the immune system that help you when you're infected with a bacteria or a virus, but that we now know the same parts of the immune system damage your body over time -- especially the blood vessels in your heart, in your brain. So the overall take home message here is that stress is a very nonspecific factor that increases the risk for a lot of illness, and really all the serious modern illnesses.