神経性無食欲症
Anorexia nervosa is characterized by the severe restriction of food intake that results in a significant weight loss. There are two subtypes of anorexia, restricting type and binge-eating/purging type. While historically researchers have found that anorexia typically begins during puberty, recent epidemiological studies have found that the average age of onset of anorexia nervosa has moved from the previously from an average age of onset of 13–17 to a current younger age of onset of 9–12. Among individuals with an eating disorder, 86% report the onset of the eating disorder by age 20, and 43% report the onset between the ages of 16 and 20.6. Corresponding with the age of onset, 95% of the population with current eating disorders are between the ages of 12 and 25.