In 2002, researchers compared severe acne in college students during a relatively stress- free period and during a highly stressful exam period. After adjusting for other variables such as changes in sleep or diet, the researchers concluded that increased acne severity was strongly correlated with increased levels of stress. Learning about the study, your roommate is surprised. " Acne is a skin disease," your roommate says. " I don't see how it could have anything to do with your mental state. "How would you weigh in on the role of stress in medical diseases? What other examples could you give of ways in which stress can affect health?