Anorexia Nervosa

To be diagnosed as having anorexia nervosa, according to the DSM-IV-TR, a person must display:

-Refusal to maintain body weight at or above a minimally normal weight for age and height (e.g., weight loss leading to maintenance of body weight less than 85% of that expected; or failure to make expected weight gain during period of growth, leading to body weight less than 85% of that expected).
-Intense fear of gaining weight or becoming obese.
-Disturbance in the way in which one's body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or denial of the seriousness of the current low body weight.
-In postmenarcheal, premenopausal females (women who have had their first menstrual period but have not yet gone through menopause), amenorrhea (the absence of at least three consecutive menstrual cycles).
Or other eating related disorders.

Furthermore, the DSM-IV-TR specifies two subtypes:

Restricting Type: during the current episode of anorexia nervosa, the person has not regularly engaged in binge-eating or purging behavior (that is, self-induced vomiting, over-exercise or the misuse of laxatives, diuretics, or enemas)

Binge-Eating Type or Purging Type: during the current episode of anorexia nervosa, the person has regularly engaged in binge-eating OR purging behavior (that is, self-induced vomiting, over-exercise or the misuse of laxatives, diuretics, or enemas).