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Anorexia Nervosa

Extreme concern about body shape and weight that results in a long-term refusal to eat and severe loss of weight

  • Usually develops in early adolescence
  • More common in females
  • Sometimes runs in families
  • Social and job-related pressure to be slim is a risk factor

People with anorexia nervosa tend to be obsessively preoccupied with their body shape and weight. Often they have a distorted body image and, against all evidence to the contrary, are convinced that they are fat, even when they are very thin. They deliberately lose weight by various means, including dieting, exercising excessively, vomiting, and using laxatives. They often go to great lengths to conceal these strategies and hide their weight loss from others.

The condition can cause changes in hormone levels that may affect growth during adolescence and menstruation in girls and women. In severe cases, the loss of weight may be life-threatening.

Anorexia nervosa occurs mainly in the developed world. It is most common in girls and young women, but it can affect people of all ages and in recent years has become more common in younger children and also in boys and men. Anorexia nervosa may run in families and may be associated with the binge-eating disorder bulimia.

What are the causes?

Anorexia nervosa often develops following a normal weight-loss diet. In Western culture, the importance placed on having a slim body leads many people of normal size to diet unnecessarily, particularly if they lack self-confidence. Sometimes, the condition is triggered by stress or depression.

Anorexia nervosa often affects young people who are under pressure to succeed in a family that overemphasizes achievement. In these circumstances, a teenager may feel driven to take control over an aspect of his or her life by refusing to eat. The condition has become an occupational hazard for people such as models, gymnasts, and ballet dancers, who are required to be extremely slim to succeed in their profession.

Wasting due to anorexia nervosa

What are the symptoms?

Almost everyone attempts to lose some weight from time to time, and teenagers are usually especially anxious to be slim. However, normal dieting needs to be distinguished from anorexia nervosa, in which a person who is already of average or low weight follows a weight-loss diet for a prolonged period. Symptoms and behaviour patterns that may be apparent early in the disorder include:

  • Refusal to eat, particularly foods that are high in calories.

  • An obsessional interest in the subject of food.

  • Preoccupation with body weight and body size.

  • Weight loss that may be concealed by wearing baggy clothes.

  • A conviction that one is overweight.

  • Use of appetite suppressants and laxative drugs.

  • Exercising excessively.

Depression may develop as a complication and lead to self-harm and suicide attempts (see Attempted suicide and suicide). Physical symptoms may appear gradually over weeks or months and become more obvious and extreme as the condition develops. They include:

  • Extreme weight loss.

  • Muscle wasting.

  • Swollen ankles.

  • Fine body hair on the trunk and limbs.

  • In women, an absence of menstrual periods (see Amenorrhoea).

If anorexia nervosa develops before or around the onset of puberty, the development of adult sexual characteristics may be delayed or stop (see Abnormal puberty in females).

If there is a continued refusal to eat, extreme weight loss leads to complications such as chemical imbalances in the blood, nutritional deficiencies, loss of bone density (see Osteoporosis), infertility, chronic heart failure, and eventually death.

How is it diagnosed?

A person with anorexia nervosa is usually reluctant to admit that there is a problem. Often a concerned parent or friend consults the doctor first. The doctor will examine the affected person to assess the degree of weight loss and exclude other causes of weight loss, such as a digestive disorder or cancer. He or she will arrange for blood tests to see if an imbalance of chemicals in the blood has developed. The doctor will also look for an underlying or associated psychological disorder, such as depression.

What is the treatment?

Treatment is often difficult because of the person’s refusal to acknowledge the illness. If the person’s weight is very low or there is a risk of self-harm, he or she may be admitted to hospital. In less severe cases, treatment can be carried out at home under the doctor’s supervision. Initially, the doctor sets a healthy weight target and monitors weight gain on a weekly basis. A dietitian will talk to the person about the importance of nutrition in general health and plan a healthy, balanced diet. In hospital, a person with anorexia nervosa is closely observed while eating habits are carefully monitored and modified until an agreed-upon weight has been achieved. At home, family members or a friend may be asked to closely monitor the person’s diet.

People with anorexia nervosa are usually referred for psychological therapy. The doctor may suggest cognitive–behavioural therapy to help an affected person develop a more realistic self-image or behaviour to bring about changes in abnormal behaviour. Family therapy may be arranged if it appears that family problems are contributing to the disorder. Antidepressant drugs may be given if there are symptoms of depression.

What is the prognosis?

About 1 in 5 people makes a complete recovery following treatment, but the same number remain severely ill. Even when a person has achieved his or her weight target, he or she needs continued professional support to maintain it.

For the remaining 3 in 5 people, the disorder persists but fluctuates in severity. Some people gain enough weight to recover but retain abnormal eating habits. Symptoms may also recur in response to stress. In some cases, bulimia develops up to 5 years after anorexia nervosa is first diagnosed.

About 1 in 20 people with anorexia nervosa dies from complications caused by malnutrition or commits suicide as a result of severe depression.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

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