AN is a syndrome of unknown etiology which has been well described since 1873, and which occurs most frequently in adolescent women. The syndrome is characterized by distorted body image, and fear of obesity, why low ideal weight is pursued. The disorder occurs in different degrees of severity with secondary endocrine and metabolic changes and disturbances. The symptoms may also include excessive physical activity, abuse of laxatives, or diuretics and self-induced vomiting.