Diagnosing Anorexia Nervosa...

The most commonly used criteria for diagnosing anorexia are from the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) and the World Health Organization's International Statistical Classification of Diseases and Related Health Problems (ICD).

Although biological tests can aid the diagnosis of anorexia, the diagnosis is based on a combination of behaviour, reported beliefs and experiences, and physical characteristics of the patient. Anorexia is typically diagnosed by a clinical psychologist, psychiatrist or other suitably qualified clinician.

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

1. 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).

2. Intense fear of gaining weight or becoming fat.

3. 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.

4. 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).

5. 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).

The ICD-10 criteria are similar, but in addition, specifically mention

1. ways that individuals might induce weight-loss or maintain low body weight (avoiding fattening foods, self-induced vomiting, self-induced purging, excessive exercise, excessive use of appetite suppressants or diuretics);

2. physiological features, including "widespread endocrine disorder involving hypothalamic-pituitary-gonadal axis is manifest in women as amenorrhoea and in men as loss of sexual interest and potency. There may also be elevated levels of growth hormones, raised cortisol levels, changes in the peripheral metabolism of thyroid hormone and abnormalities of insulin secretion"; and

3. if the onset is before puberty, development is delayed or arrested.