What Is It?

Anorexia nervosa is an eating disorder in which a person limits eating and weighs at least 15% less than her ideal weight. At least 90% of cases are in young women, but anorexia nervosa can occur in men. It rarely occurs before puberty or after age 40.

A person with this disorder fears being fat. She may be completely convinced that she is overweight despite what the scale shows or what other people say. To achieve or maintain leanness, she may exercise obsessively or use laxatives. Because a super-restrictive diet requires exquisite control, she may become quite careful, inhibited and controlled in other areas of life. For example, she may retreat from social contacts or may perform ritual behaviors.

The term anorexia literally means having a lack of appetite, but this is misleading because people with the disorder usually have a strong appetite or even a craving for food that they actively suppress. They diet to the point of starvation. The disorder is defined not by whether a person feels hunger but by how much weight he or she has lost.

Anorexia nervosa is most often diagnosed in industrialized societies, in which thinness is equated with attractiveness. The problem usually begins in adolescence. In girls who diet too much, the beginning of menstruation may be delayed or it may stop once it has started. Anorexia nervosa affects about 1 in 100 to 200 girls or women in the United States.

The cause of anorexia nervosa is not clear. It is likely a combination of genetic (inherited) and environmental factors. Here are some proposed causes:

• A variant of depression or anxiety - Anorexia, depression, anxiety and obsessive-compulsive disorder tend to run in families, and many people with anorexia nervosa have symptoms of depression or obsessive-compulsive disorder.

• A consequence of fears about becoming an adult - One may be fear of sexual feelings and activities that begins in adolescence. Sometimes a life event linked to normal development, such as moving away from home, triggers the illness.

• Environmental pressures - Cultural influences, including images from television and film and pressure from peers, leave the impression that thin is best. But culture is only part of the story. The illness was reported hundreds of years ago when social pressures were quite different.

• Difficult family relationships - Family difficulties can be a cause of the illness, but their importance may have been overemphasized in the past. Sometimes family problems develop after the disease has started, because a person with anorexia nervosa may test the patience of those she lives with. People with the disorder describe a feeling of power and control over others through their dieting.