Eating disorders are relatively common psychiatric disorders most often observed in late adolescent and young adult females, with typical onset during adolescence (ages 12–18 years). Eating disorders may be chronic and relapsing conditions and are often associated with significant medical morbidity and psychiatric comorbidity. The etiology, maintaining factors, and treatment of eating disorders have been understudied, particularly in regard to children and adolescents. DSM-IV (American Psychiatric Association 1994) and its text revision, DSM-IV-TR (American Psychiatric Association 2000a), include three eating disorder diagnoses: 1) anorexia nervosa (AN) and 2) bulimia nervosa (BN), which each have specific criteria; and 3) eating disorder not otherwise specified (EDNOS), which is a more heterogeneous diagnosis capturing clinically significant eating disorder presentations that cannot be categorized as AN or BN.