The distinct focus of the clinical health psychologist is on physical health problems. A clinical health psychologist has special expertise or training in clinical health psychology and applies scientific knowledge of the interrelationships among behavioral, emotional, cognitive, social and biological components in health and disease to the promotion and maintenance of health; the prevention, treatment and rehabilitation of illness and disability; and the improvement of the health care system. Clinical health psychologists are dedicated to the development of knowledge regarding the interface between behavior and health, and to the delivery of high quality services based on that knowledge to individuals, families, and health care. Source: American Psychological Association Commission for the Recognition of Specialties and Proficiencies in Professional Psychology, 2008. [1/1/2007: new, 7/1/2008: definiton added, source added]