What is anorexia nervosa?

The cause of anorexia nervosa is unknown. Both biological and social factors play a part. People in certain professions, such as modeling and ballet dancing, are especially at risk.

Anorexia nervosa is an eating disorder affecting mainly girls or women, although boys or men can also suffer from it. It usually starts in the teenage years.

It is difficult to estimate how common it is but surveys suggest that up to 1 per cent of schoolgirls and female university students have anorexia nervosa. This may be an underestimate.

How is the disease characterised?

Body weight is maintained at least 15 per cent below that expected for a person's height.

It is self-induced weight loss caused by avoiding fattening foods and may involve taking excessive exercise, using laxatives or diuretics or self-induced vomiting.

There is a strong, almost overwhelming fear of putting on weight, with sufferers preoccupied with the shape or size of their bodies.

Rules are invented regarding how much food is allowed and how much exercise is needed after eating certain amounts of food.

Those suffering from anorexia pursue a very low 'ideal'weight.

The weight loss may cause hormonal disturbances and women with anorexia nervosa may stop having periods.

Why do some people get anorexia?

The cause of anorexia nervosa is unknown, although it is likely that both inherent biological factors and factors in the patient's social environment play a part. The disease is mainly encountered in the western world and is more common among women in certain professions, such as models and ballet dancers. Puberty, deaths in the family and other life stresses are all believed to be potential triggers of anorexia.

There may also be peer pressure to lose weight, nasty comments from others about weight that trigger dieting or an unrealistic expectation of what a normal body weight should be.

What are the signs and symptoms of anorexia nervosa?

Weight loss of at least 15 per cent below the normal ideal body weight for a person of the same age and height.

Cessation of periods or delayed development in puberty.

Self-induced weight loss. Methods can include fasting, low food intake, excessive exercise, diuretic medicines (medicines that make you urinate more), laxatives, diet pills or vomiting. Sometimes people make themselves sick to lose weight. Others take excessive exercise.

Sufferers have a constant fear of gaining weight, as well as a feeling of being fat, even when their weight is much less than that of other people of the same height.

Sufferers may feel bloated, even after a small meal.

They may lose interest in socialising with friends.

Other side effects include tiredness, feeling cold, constipation and stomach ache.

Some patients also develop additional disorders such as bulimia.

How long can anorexia last?

The sooner the treatment is started, the better the chance of recovery. However, anorexia may last for months or years, and it can take many more years before normal weight is regained.

Severe anorexia

People who do not receive treatment may become chronically ill or even die.

Long spells without adequate intake of food can cause osteoporosis (fragile bones) and damage to the heart, liver, kidneys and brain.

Anorexia can impede growth in the young and cause difficulties in concentration.

People with anorexia nervosa may also experience mental health problems such as depression and increased risk of suicide.

How is anorexia treated?

Treatment will vary depending on the individual circumstances. There is no one single treatment that has proven to be effective in all cases. Treatment aims to:

• restore the person to a healthy weight.
• restore healthy eating patterns.
• treat any physical complications or associated mental health problems.
• address thoughts, feelings and beliefs concerning food and body image.
• enlist family support.

In some cases, medication is necessary, especially where there is depression or serious compulsive symptoms. Treatment by the family doctor is possible, although sometimes a psychologist or psychiatrist experienced in eating disorders is necessary.

If the weight loss becomes serious (more than 20 to 25 per cent less than total normal body weight) admission to hospital may be required. Treatments used include individual psychological therapy, family therapy and drug therapy using antidepressants.

What can people suffering from anorexia do to help themselves?

Anorexia nervosa is a potentially life-threatening illness, and should be treated as soon as possible. Sufferers should seek help, or be encouraged to do so.

Self-help organisations for anorexia nervosa are usually run by people with personal experiences of eating disorders. There are also self-help books available.

Based on a text by Dr Ren Stving, Dr Kirsten Hrder and Dr Paul Klenerman of the UK