The International Statistical Classification of Diseases and Related Health Problems, tenth revision - ICD-10

The World Health Organisation defines eating disorders under the ICD-10. Under the ICD-10, the following are recognised as eating disorders: Anorexia Nervosa; Bulimia Nervosa; Overeating Associated with Other Psychological Disturbances; and Other Eating Disorders.

Anorexia Nervosa

According to the ICD-10 criteria (as outlined by the World Health Organisation), for a definite diagnosis of Anorexia Nervosa, all the following are required:

• Body weight is maintained at least 15% below that expected (either lost or never achieved), or Body Mass Index (BMI)  is 17.5 or less. Pre-pubertal patients may show failure to make the expected weight gain during the period of growth. 

• The weight loss is self-induced by avoidance of 'fattening foods' and one or more of the following: self-induced vomiting; self-induced purging; excessive exercise; use of appetite suppressants and/or diuretics. 

• There is body-image distortion in the form of a specific psychopathology whereby a dread of fatness persists as an intrusive, overvalued idea and the patient imposes a low weight threshold on himself or herself. 

• There is endocrine disorder, manifesting in women as loss of periods (amenorrhoea) and in men as a loss of sexual interest and potency. 

• If onset is pre-pubertal, the sequence of pubertal events is delayed or even arrested (growth ceases; in girls the breasts do not develop and the onset of periods is delayed; in boys the genitals remain juvenile). With recovery, puberty is often completed normally, but the menarche is late. 

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Bulimia Nervosa

According to the ICD-10 criteria, for a definite diagnosis, all the following are required:

• There is a persistent preoccupation with eating, and an irresistible craving for food; the patient succumbs to episodes of overeating in which large amounts of food are consumed in short periods of time. 

• The patient attempts to counteract the ‘fattening’ effects of food by purging, starving and other strategies. 

• The psychopathology consists of a morbid dread of fatness and the patient sets herself or himself a sharply defined weight threshold, well below the weight that constitutes the optimum or healthy weight in the opinion of the physician. There is often, but not always, a history of an earlier episode of anorexia nervosa, the interval between the two disorders ranging from a few months to several years. 

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