How Can Stress Cause So Many Different Diseases?

Many of these effects are due to increased sympathetic nervous system activity and an outpouring of adrenaline, cortisol and other stress-related hormones.  Certain types of chronic and more insidious stress due to loneliness, poverty, bereavement, depression and frustration due to discrimination are associated with impaired immune system resistance to viral linked disorders ranging from the common cold and herpes to AIDS and cancer. 

Stress can have effects on other hormones, brain neurotransmitters, additional small chemical messengers elsewhere, prostaglandins, as well as crucial enzyme systems, and metabolic activities that are still unknown.  Research in these areas may help to explain how stress can contribute to depression, anxiety and its diverse effects on the gastrointestinal tract, skin and other organs.

Source: The American Institute of Stress, www.stress.org