As we have learned more about the relationships between stress and illness, we have been able to clearly delineate pathways by which stress may interfere with health maintenance and contribute directly to disease etiology and progression. Sympathetic nervous system arousal that drives many of the biological sequelae of stress appears to affect atherosclerosis, hypertension-related blood pressure changes, and a host of other pathogenic processes important in behaviorally-mediated disease. Although much of the research in behavioral medicine has focused on stress-related physiological changes and heart disease, there are rapidly growing research efforts addressing immune and endocrine changes and their effects on infectious disease, AIDS, diabetes, and other diseases.
A second pathway by which stress may alter health is less direct. We know that stress affects behavior in ways that can affect health. For example, it is widely believed that stress increases already established drug use, including cigarette use, caffeine consumption, and use of alcohol. To varying extents, such behavior appears to contribute to disease. Similarly, stress may interfere with important health-maintenance activities: Exercise, diet, and other valuable behaviors may decrease or disappear during or after substantial stress. In addition, specific regimens designed to prevent or control already established disease may not be followed during stressrelated episodes of negative affect or disruption of daily routine. Thus, maintenance of preventive behaviors or use of drugs to control diseases such as diabetes or hypertension may be more difficult during stress.
A third pathway is closely related to the second. Illness behavior, loosely defined as actions that characterize ill individuals or that affect treatment,