Patient information

What are the causes of eating disorders?

The cause of eating disorders is not known. The vulnerability may be a combination of genetics, difficulties regulating emotions, rigid thinking styles, difficulties managing external stressors and psychiatric illnesses such as depression and anxiety. It is reasonable to suggest that cultural pressures can lead to dissatisfaction with one’s body and dieting behaviours, and a small vulnerable percentage go on to develop the full-blown illness.

Who gets eating disorders?

Eating disorders can affect 5–10% of young women. Anorexia Nervosa normally occurs in 0.5–1% of adolescent and young adult females, with a peak onset between 14 to 18 years of age. Forty percent of all cases are between 15 to 19 years of age. However, the remaining 60% are over 20 years old. Bulimia Nervosa occurs in 2–4% of adolescent and young females between 15 to 30 years of age. Females make up 90% of the patients. Patients will often meet criteria for different eating disorders over the course of their illness.

What is the usual course of eating disorders?

Over 50% of cases with Anorexia Nervosa will recover within five years of onset, 25% will partially recover and 25% will have a poor outcome. Of this chronic group, 20% will die within 20 years. The average duration of the illness is seven years.

Similarly with Bulimia Nervosa, 50% will recover, 30% will make a partial recovery and 20% will continue to have a chronic course. A significant number will recover within 10 years. Mortality is 1–2%, with suicide being the most common cause of death.

What are the medical consequences of eating disorders

Anorexia Nervosa affects most organ systems, including the heart, brain, gastrointestinal system and reproductive system, but these will recover with weight restoration. However, the skeletal system can be depleted as poor nutrition coincides with the critical period of peak bone mass deposition. The only established treatment is weight restoration; the place of hormone replacement therapy is uncertain.

Vomiting and laxative abuse in Anorexia Nervosa and Bulimia Nervosa can lead to electrolyte disturbances, dental erosion and long lasting disruption to bowel functioning.

What does treatment involve?

The cornerstones to treatment are:

• stabilisation of medical status
  
• stabilisation of nutritional status – establishing healthy eating patterns and normalising weight
  
• stabilising other psychiatric illness – for example, depression, bipolar disorder, anxiety disorders
  
• psychological skills to help with thoughts, urges and emotions
  
• involving and educating families as much as possible.

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