Previous research has pointed to a link between poor sleep in children and an increased risk of drug use. Now new research from the University of California, San Diego has confirmed this and also suggests that bad sleep can spread throughout social networks. The study covered 8,349 children between year 7 and year 12 and found that children who slept less than seven hours a night were 19% more likely to take drugs. By mapping the social networks of the children the researchers found that the friends of children who slept badly were 29% more likely to sleep badly themselves. This influence carried on through up to four degrees of separation although it diminished as the connections between people got more remote. Lack of sleep is also linked to behavioural, cognitive and emotional problems and the study recommended that children got an average of between 8 1/2 and 9 1/4 hours sleep a night.
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