Over the last 30 years numerous studies in the fields of psychology, sociology and anthropology have shown that those individuals who are currently, or have recently undergone, severe grief, poverty, job dissatisfaction, prejudice, cultural dislocation or other isolating or despondence causing situations, have a higher incidence of illness and death than those who feel fulfilled in their social and their personal world. Studies have shown that mood and attitude, as well as belief systems, can affect nearly every chronic illness studied. Specifically, hopelessness and helplessness, as well as cynicism, have been shown to have detrimental effects on health. A sense of control and hopefulness, as well as good humor and courage, have beneficial effects. Optimistic people are typically less likely to become ill. When they do become ill they tend to be ill for less time. Optimistic people typically live longer.