Determinants of Health and Health Belief Models

Health psychology begins with a simple but powerful observation: whether a person stays well or becomes ill is not decided by biology alone. Two people can carry the same genetic risk for heart disease, yet one develops it in middle age while the other lives a long, active life. To explain such differences, health psychologists reject the older biomedical model, which treated illness purely as a physical malfunction, in favor of the biopsychosocial model proposed by George Engel in 1977. This framework argues that health is shaped by the constant interaction of three sets of determinants. Biological factors include genetics, immune function, and the physiological effects of aging. Psychological factors cover beliefs, emotions, stress, and health-related behaviors such as smoking or exercis