A host of medical experts are coming to the opinion that sleep deprivation may be a much more important cause of childhood hyperactivity than previously thought. Sleep experts feel that many children would take greater benefit from a few hours sleep than being dosed up with medicines such as Ritalin.

'Sleep problems have always been recognised as a syptom of ADHD,' Dr Stephen Sheldon director of sleep medicine at the Children's Memorial Hospital in Chicago tells The Times today, 'but they are as likely to be a cause. Children become hyperactive rather than sleepy when they are severely sleep-deprived.'

Several academic studies of children and their sleep habits seem to support his theory. Tel Aviv University compared two groups of nine to 11-year-olds, one of which had had one hour more sleep for a period of five nights. The group which had slept longer performed significantly better at tests on memory, recognition and reaction.

Some scientists are coming to the conclusion that drugs such as Ritalin are being prescribed in cases to children who simply need more sleep. A study by the University of Louisville on a group of five to seven-year-olds diagnosed with mild ADHD discovered that a quarter of them had mild sleep apnoea (temporary blockage of their airways). When this was treated, their behaviour improved.

'It's terrible that children are tagged with a medical condition before the simple behavioural solutions for what might be simple sleep deprivation have even been contemplated,' says Professor Lyn Quine, a health psychologist at Kent University. 'If [a child's] behaviour is disruptive, parents need to address the sleep issue first because overactivity and poor concentration are often signs of tiredness.'

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