Section 7. Mental Health Disorders

Chapter 103. Eating Disorders

Topics: Introduction | Anorexia Nervosa | Bulimia Nervosa | Binge Eating Disorder

Anorexia Nervosa

Anorexia nervosa is characterized by a distorted body image, an extreme fear of obesity, refusal to maintain a minimally normal body weight, and in women, the absence of menstrual periods.

Hereditary factors have been shown to play a role in the development of anorexia nervosa. Social factors are also important. The desire to be thin pervades Western society, and obesity is considered unattractive, unhealthy, and undesirable. Even before adolescence, children are aware of these attitudes, and two thirds of all adolescent girls diet or take other measures to control their weight. Yet only a small percentage of these girls develop anorexia nervosa. Other factors, such as psychologic susceptibility, probably predispose certain people to developing anorexia nervosa. In areas with a genuine food shortage, anorexia nervosa is rare.

About 95% of people who have anorexia nervosa are female. The disorder usually begins in adolescence, occasionally earlier, and less commonly in adulthood. Anorexia nervosa primarily affects people in middle and upper socioeconomic classes. In Western society, the number of people who have this disorder seems to be increasing: it has been estimated to affect about 1% of girls aged 12 to 18.

Symptoms

Anorexia nervosa may be mild and transient or severe and persistent. Because many people who develop anorexia nervosa are meticulous, compulsive, and intelligent, with very high standards for achievement and success, an eating disorder may easily go undetected. The first indications of the impending disorder may be a subtle increased concern with diet and body weight. Such concerns seem out of place, because most people who have anorexia nervosa are already thin. Preoccupation and anxiety about weight intensify as the person becomes thinner. Even when emaciated, the person claims to feel fat, denies that anything is wrong, does not complain about weight loss, and usually resists treatment. The person usually does not see a doctor until brought to one by concerned family members.

Anorexia means "lack of appetite," but people who have anorexia nervosa are actually hungry and preoccupied with food. They study diets and count calories; they hoard, conceal, and deliberately waste food; they collect recipes; and they prepare elaborate meals for others. Half of the people who have anorexia nervosa binge and then purge by vomiting or taking laxatives. The other half simply restrict the amount of food they eat. They also frequently lie about how much they have eaten and conceal their vomiting and their peculiar dietary habits. Many also take diuretics to treat perceived bloating.

Women with anorexia nervosa stop having menstrual periods, sometimes before losing much weight. Women and men with the disorder may lose interest in sex. Typically, they have a low heart rate, low blood pressure, low body temperature, swelling of tissues caused by fluid accumulation (edema), and fine, soft hair or excessive body and facial hair. People with anorexia nervosa who become very thin tend to remain active, often exercising excessively to control their weight. Until they become emaciated, however, they have few symptoms of nutritional deficiencies. Depression is common.

Hormonal changes resulting from anorexia nervosa include markedly reduced levels of estrogen (in women) and thyroid hormone and increased levels of cortisol. If a person becomes seriously malnourished, every major organ system in the body is likely to be affected. When weight loss has been rapid or severe--for example, to more than 25% below the ideal body weight--restoring body weight quickly is crucial; such weight loss and the associated changes in electrolytes and fluid balance can be life threatening. Problems with the heart and with fluids and electrolytes (sodium, potassium, chloride) are the most dangerous. The heart gets weaker and pumps less blood through the body. The person may become dehydrated and prone to fainting. The blood may become alkaline (a condition called metabolic alkalosis (see Section 12, Chapter 159)), and potassium levels in the blood may decrease. Vomiting and taking laxatives and diuretics can worsen the situation. Sudden death, probably from abnormal heart rhythms, may occur.

Diagnosis and Treatment

Anorexia nervosa is usually diagnosed on the basis of severe weight loss and the characteristic psychologic symptoms. The typical person with anorexia nervosa is an adolescent girl who has lost at least 15% of her body weight, fears obesity, stops having menstrual periods, denies being sick, and otherwise appears healthy.

Treatment has two phases: short-term intervention to restore body weight and save the person's life and long-term therapy to improve psychologic functioning and prevent relapse.

The initial treatment of severe or rapid weight loss is best provided in a hospital where experienced staff members firmly but gently encourage the person to eat. Rarely, the person is fed intravenously or by a tube inserted through the nose and passed into the stomach. Sometimes doctors confine those with severe disease in the hospital against their will after obtaining appropriate legal authorization from a parent, guardian, or the court.

When the person's nutritional status is acceptable and stabilized, long-term therapy is begun. Treatment is aimed at establishing a calm, concerned, stable environment while encouraging the consumption of an adequate amount of food. This treatment may include individual, group, and family psychotherapy as well as drug therapy. Combined treatment by the family doctor and a therapist often helps, and consultation with or referral to a specialist in eating disorders is wise.

When depression is diagnosed, antidepressants are prescribed. Certain antidepressants, particularly selective serotonin reuptake inhibitors, are useful for preventing relapse after weight has been restored.

As many as 10 to 20% of people diagnosed with anorexia nervosa die of it and its complications, which include fluid and electrolyte abnormalities, heart failure, and suicide resulting from depression. However, because mild cases may not be diagnosed, no one knows exactly how many people have anorexia nervosa or what percentage die of it.