DRugs should not be used to treat people suffering from anorexia, the Government's medicines watchdog said yesterday. In new guidance on the treatment of eating disorders - which affect children as young as eight - the National Institute for Clinical Excellence says sufferers should be offered psychological treatments and family support.

More than one million people in Britain suffer from eating disorders and numbers are growing, putting increased pressure on the NHS.

Patients who have problems with eating are often regarded by family doctors as suffering from stress or depression and treated with antidepressants.

But the institute says those suffering from anorexia may have heart problems caused by the condition which could be accentuated by the drugs. "In patients with anorexia nervosa at risk of cardiac complications, the prescription of drugs with side effects that may compromise cardiac functioning should be avoided," the guidance says.

The drugs which could cause problems include antipsychotics, antidepressants, some antibiotics and some antihistamines. Where prescription of the drugs is essential,the institute says patients should have regular electrocardiogram checks. One in 250 women and one in 2,000 men experiences anorexia in adolescence and about half of sufferers are teenage girls aged between 13 and 19.

Andrea Sutcliffe, from the institute, said: "The availability of NHS services for people with eating disorders varies across England and Wales. This guideline is an important step in standardising the care available to people with eating disorders."

Bulimia, the binge-eating disorder, is more common than anorexia, and affects about five times as many people. The guidance says that sufferers from bulimia should be offered cognitive behaviour therapy, a form of psychological treatment, as a first step but that treatment with antidepressant drugs may also be offered "as an alternative or additional first step".

Simon Gowers, child psychiatrist at the Eating Disorders Service for Cheshire and Merseyside, said: "The prevalence of eating disorders in the general population is an increasing problem. While each patient will have their own individual needs, this guideline gives clear recommendations on the types of treatment that should be made available."