These questions lie at the heart of health psychology.
Health psychologists study how the mind and behavior influence physical health.
They also study how physical health influences the mind and behavior. Clinical health psychologists take the scientific knowledge obtained from research in health psychology and apply it to patients with physical and emotional illnesses. They are interested in preventing illness, in treating those who are ill, and in improving peoples' general physical and mental well being. They are knowledgeable about the critical interrelationships between behavior, mental health, physical diseases, interpersonal relationships, the health-care delivery system, and optimum health. Clinical health psychologists work with patients to modify the effects of stress, lifestyle, and personality functioning in optimizing health and preventing and treating illness.