The findings, published in the November/December 2006 issue of the journal Child Development, are based on questionnaires completed by 300 pairs of 8-year-old twins and their parents in England and Wales. The researchers chose to study twins because such studies provide an opportunity to look at both genetic and environmental influences on a range of sleep characteristics and problems.

In the study, children reported more frequent sleep problems than their parents acknowledged. For example, 45 percent of children said they usually had difficulties falling asleep, while only 17 percent of parents reported this to be the case in their children.

The authors speculate that there may be many explanations for this discrepancy. For example, regarding night waking, parents may be unaware when their children wake during the night if the children go back to sleep easily. The inconsistency may also be due to difficulties children experience in reporting their problems, which may lead them to overestimate their troubles. Regarding delays in falling asleep, children, like adults, may over-estimate their sleep problems because of the way in which memory is processed around sleep in people who report certain sleep difficulties, such as insomnia.

It may be helpful for parents to ask their children directly about their sleep patterns and any difficulties they are encountering. Further research should be done to determine whether children are accurate reporters of their sleep problems.

The study also found some ties between different sleep problems. For example, children who resisted going to sleep were also more likely to have trouble falling asleep.

The authors examined the extent to which children's sleep problems are caused by genes and by environmental factors. They conclude that reports by parents suggest that genes play a larger role in most children's sleep problems compared to children's own reports. This could be explained by rater bias (that is, parents may accentuate similarities between their identical twins), or it could be that children and parents report on different aspects of sleep problems.

Regardless of who is providing the information, both genetic and environmental influences are likely to influence most of the sleep problems the study assessed. This means that some children could be more vulnerable than others for certain sleep difficulties as a result of their genes. Environmental influences (such as bullying at school, illness, and other stressors) were even more significant than genetic influences for most of the sleep problems.

Summarized from Child Development, Vol. 77, Issue 6, A Twin-Study of Sleep Difficulties in School-Aged Children by Gregory, AM, Frühling, VR, and Eley, TC (University of London). Copyright 2006 The Society for Research in Child Development, Inc. All rights reserved.

Note: If no author is given, the source is cited instead.

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