Anorexia nervosa facts
Anorexia nervosa is a psychiatric condition, which is part of a group of eating disorders.
The cause of anorexia has not been definitively established, but self-esteem and body-image issues, societal pressures, and genetic factors likely each play a role.
Anorexia affects females far more often than males and is most common in adolescent females.
http://www.medicinenet.com/anorexia_nervosa/article.htm