Nobel Laureate Barry Marshall (co discoverer of Helicobacter Pylori, cause of stomach ulcers) gave a talk to a graduating class at the university he went to (can't find link, but it's on the net somewhere). He talks about "stress" being a fertile area of research for medical advances. His argument is that stress is rarely the direct cause of anything. It might be a secondary cause, or it might be a symptom, but research into ailments currently attributed to "stress" is a really good direction for the aspiring young medical research scientists out there.