FRIDAY, Jan. 5 (HealthDay News) -- Sleep problems and depression often go hand-in-hand in children, new research shows.

A study published in the Jan. 1 issue of Sleep found that children with sleep disturbances are more severely depressed, have more depressive symptoms, and have more anxiety disorders, compared to children without sleep disturbances.

The study by researchers at the University of Pittsburgh included 553 children with a depressive disorder.

Almost three-quarters of the children had sleep disturbance -- 53 percent had insomnia alone, 9 percent had hypersomnia (excessive sleepiness) alone, and 10 percent had both disturbances. Girls were more likely to have sleep disturbance than boys.

Among the sleep-disturbed participants, those with both insomnia and hypersomnia had a longer history of illness, were more severely depressed and were more likely to have weight loss, fatigue, and other problems, compared with participants with either insomnia or hypersomnia.

"We know that depression is associated with sleep problems. But what this study shows is that, in depressed youths, not all sleep problems are the same," lead author Xianchen Liu said in a prepared statement.

"Insomnia is the most common problem, but having a combination of insomnia and sleepiness is 'double trouble.' Youths having both of these had more severe depression than youths with just one sleep problem. This means that we should carefully ask depressed youths about the specific type of sleep problem they're having," the researcher said. "It may also mean that we should think about different treatments to specifically target an individual's sleep problem."

Experts say that children in grammar school should get 10 to 11 hours of sleep a night, while preschoolers should sleep 11 to 13 hours a night.

More information

The Nemours Foundation has more about common sleep problems.