Eating Disorders

Anorexia Nervosa

According to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) (DSM-IV-TR), the psychiatric diagnostic classification system most frequently used by clinicians and researchers in the United States, to receive a diagnosis of anorexia nervosa (AN), an individual must maintain a body weight that is significantly less than normal. The DSM-IV-TR specifically states than an individual with AN must weigh less than 85% of the [Page 308]weight considered normal for the individual's age and height; however, the DSM-IV-TR does not refer clinicians to a specific source to establish normal weight and, in fact, encourages clinicians to consider normal weight in light of individual factors such as body build. The current International Classification of Diseases (ICD-10), an alternative diagnostic classification system, specifies a more stringent standard for abnormally low body weight in AN; specifically, a body massindexof17.5orless.

To receive a diagnosis of AN according to DSM-IVTR criteria, in addition to low body weight, an individual must also display an intense fear of gaining weight or becoming fat and a disturbance of certain weight-and shape-related thoughts. For example, an individual with AN may misperceive her body shape or size (believing she is larger than she really is), may use her weight as the only or the most important criterion against which she evaluates her self-worth, or may deny the seriousness or dangerousness of her low weight.

For women old enough to menstruate, the DSMIV-TR also requires amenorrhea (absence of menstruation over several menstrual cycles) to make a diagnosis of AN. The reason for including amenorrhea as a criterion is that women who are abnormally thin or who have an abnormally low percentage of body fat frequently stop menstruating. However, because many women take hormonal birth control medications that cause regular menstruation regardless of body composition, this criterion can be difficult for clinicians to assess. Research also suggests that some women, even at very low weights, continue to menstruate, and several studies have found that deleting amenorrhea from the criteria does not reduce the quality of the AN diagnosis. For this reason, many researchers believe that amenorrhea will no longer be a requirement for a diagnosis of AN in the future.

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