Eating Disorders "Not Otherwise Specified," or EDNOS, is a term used in the psychiatry world to describe eating disorders that do not fall into the strict categories of Anorexia Nervosa or Bulimia Nervosa. Although many families are relieved to learn "it's not anorexia" or "it's not really bulimia," this is a serious misunderstanding. Half of all eating disorder cases fall into the EDNOS category and outcomes in EDNOS are no less serious. In addition, the same patient may pass in and out of the EDNOS category over time.

Doctors are required to make diagnoses based on strict categories, so a patient who is indeed quite ill but has unusual symptoms or is too young to display certain symptoms needs treatment as much as another patient who does fall under the category. NOS is a term used in other conditions as well, such as Pervasive Developmental Disorder, Bipolar Disorder, and cancers.

Except for two distinct eating disorder behaviors, the EDNOS diagnosis and treatment are similar to that of anorexia and bulimia. The two exceptions are: chewing and spitting out foods, and Binge Eating Disorder. The DSM, which is periodically updated, may take a different stance on both of those behaviors in the next update, due in May 2012.