This is a very real possibility that is being actively investigated. Stress can cause psychological as well as physical effects. New research shows that stress can affect the nervous system, immune system, and hormones in the body. Clearly, chronic stress has been associated with a variety of common ailments, such as ulcers, high blood pressure and certain types of heart disease. However, research is needed to determine if stress caused physical illness in Persian Gulf veterans. Stress would not account for all illnesses reported by Persian Gulf veterans.