Anorexia Nervosa

Definition

Anorexia nervosa, as defined in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), has four criteria. First, the individual must refuse to maintain a weight within a normal range for height and age, meaning more than 15 percent below ideal body weight. Second, the person experiences a fear of weight gain. Third, there is a severe body image disturbance, and the determination of self-worth is measured based on body image without acknowledgment of the severity of the illness. Last, in women who have begun to menstruate, amenorrhea, or the absence of three or more menstrual cycles, is part of the diagnostic criteria. Within this definition, there are two subtypes: a restricting type and a binge eating/purging type. The restricting subtype maintains a low body weight by restricting caloric intake. The binge/purge subtype will either binge (large intake of calories) or purge (using vomiting and/or laxatives to remove calories) to control their weight. The diagnosis of anorexia is still appropriate with the binge/purge subtype because there is still a body weight at 15 percent less than ideal body weight.

Epidemiology

Most often, it is females who are affected by anorexia, with males representing only 5 percent of all anorexic patients. It is estimated that up to 0.5 percent of young females meet the criteria for anorexia nervosa. Onset is usually four to five years after the onset of menarche. Overall data and trends of eating disorders are difficult to establish because the definition has changed over time and the disease often relies on self-reporting. Many studies demonstrate increasing prevalence of anorexia nervosa over the last 50 years in young women (15–24 years old) in the United States. The incidence of anorexia nervosa and other eating disorders is lower in developing countries. However, some studies suggest that an increasing westernization and modernization of these countries is contributing to a changing self-image and body image among women, and an increased reporting of anorexia.

There is no medical consensus on the etiology of eating disorders including anorexia nervosa. Most models include psychological, biological, family, genetic, environmental, and societal factors. There seems to be an even distribution of anorexia nervosa across social classes. These forces can cause a decreased sense of self-esteem, body image, or self-control. There are several more specific factors that may be influential in the development of anorexia. For example, some literature suggests that an important predictor of eating disorders is dieting during adolescence. In addition, if there is a preoccupation or obsession with thin body image or if one feels a social pressure to be thin, this may be associated with the development of eating disorders. Feminist psychology theory has suggested that societal pressure to be “super” women in the setting of Western society can predispose women to develop eating disorders. Those who are later diagnosed with anorexia are often described [Page 35]as perfectionists, often excelling in school, athletics, and interpersonal experiences. It is unclear if there is a prodrome of symptoms that precede onset of anorexia. There may be family characteristics that are associated with individuals developing eating disorders. In particular, there is an association with the experience of high parental expectations related to achievement and appearance, and settings with poor communication or marital tension.

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