Children who snore face nearly double the risk of being inattentive and Hyperactive, say scientists.
The findings reinforce evidence that suggest a link between sleep problems and attention deficit disorders. The research does not make it clear whether one condition causes the other. However, the researchers believe snoring and other sleep problems may be the culprit in some cases because children often express sleepiness by being inattentive and hyperactive. If there is indeed a cause and effect link, sleep problems in children could represent a major public health issue

Dr Ronald Chervin, sleep researcher Study co-ordinator Dr Ronald Chervin, a neurologist and sleep researcher at the University of Michigan, said: "If there is indeed a cause and effect link, sleep problems in children could represent a major public health issue. "It's conceivable that by better identifying and treating children's snoring and other night time breathing problems, we could help address some of the most common and challenging childhood behavioural issues."

Attention Deficit and Hyperactivity Disorder (ADHD) is the most common neurobehavioral disorder in childhood, affecting between 4 and 12% of school-age children. Data used by Dr Chervin suggest that between 7% and 12% of children snore frequently, with apnoea - brief breathing lapses during sleep that cause snoring - present in up to 3% of school-age children. Many other studies have identified a link between sleep problems and ADHD, but sleep specialists and psychiatrists are divided over which condition might cause the other.

Dr Stephen Sheldon, a sleep specialist at Children's Memorial Hospital in Chicago, said: "There's absolutely a connection "There is a proportion of youngsters that have sleep pathology causing their daytime symptoms that appear virtually identical to ADHD."

Tonsil removal
However, Dr Timothy Wilens, a child psychiatrist at Massachusetts General Hospital in Boston, is more sceptical. He said: "I would say the verdict is still out." A body of research also suggests ADHD is a genetically inherited disorder. Dr Wilens said sleep disturbances in ADHD children are likely to be the result of behavioural problems and not vice versa.

Dr Chervin's study, which involved 866 children aged two to 13, is published in the March issue of Paediatrics. It is based on surveys of parents about their children's behaviour and sleep patterns. Overall, 16% were frequent snorers and 13% scored high on the ADHD scale. Among frequent snorers, 22% had high ADHD scores, compared with only 12% among infrequent snorers. However, parents were not asked if their children had been diagnosed with ADHD. Professor Gregory Stores at the University of Oxford has just started a similar study in the UK, looking at the sleep patterns of a large group of children diagnosed with ADHD. He said: "There is convincing literature that sleep problems are very commonly reported in parents of children with ADHD "It makes good sense that if children persistently miss out on sleep or their sleep quality is impaired, their daytime behaviour and learning is going to be affected." Since snoring is often caused by apnoea, which in turn is frequently caused by large tonsils, removing the tonsils may in some cases improve behaviour, said Dr Chervin.