Tots who sleep less tend to have severe behavioral problems

A new study has found that 4-year-olds with shorter than average sleep times have increased rates of "externalizing" behavior problems.

"Preschool children with shorter nighttime sleep duration had higher odds of parent-reported overactivity, anger, aggression, impulsivity, tantrums, and annoying behaviors," according to the new research by Dr. Rebecca J. Scharf of University of Virginia, Charlottesville, and colleagues.

They recommend that parents and health care providers discuss steps to improve sleep habits for preschool-age children with behavior problems.

The researchers analyzed parent responses from a nationally representative study of approximately 9,000 children, followed from birth through kindergarten age.

When the children were four years old, nighttime sleep duration was estimated by asking the parents what time their child typically went to bed and woke on weekdays.

On a standard child behavior questionnaire, parents rated their child on six different "externalizing" behavior problems such as anger and aggression. (Externalizing behavior problems are outward behaviors, distinguished from "internalizing" problems such as depression and anxiety.)

The relationship between sleep duration and behavior scores was assessed, with adjustment for other factors that might affect sleep or behavior.

The average bedtime was 8:39 pm and wake time 7:13 am, giving a mean nighttime sleep duration of about 10 and a half hours. Eleven percent of children were considered to have "short sleep duration" of less than 9 hours 45 minutes (calculated as one standard deviation below the average).

On the child behavior questionnaire, 16 percent of children had a high score for externalizing behavior problems.

Behavior problems were more common for boys, children who watched more than two hours of television daily, and those whose mothers reported feeling depressed.

After adjustment for other factors, "Children in the shortest sleep groups have significantly worse behavior than children with longer sleep duration," Dr Scharf and colleagues write.

The effect was greatest for aggressive behavior problems, which were about 80 percent more likely for children with nighttime sleep duration of less than 9 hours and 45 minutes.

The study is published in the Journal of Developmental and Behavioral Pediatrics, the official journal of the Society for Developmental and Behavioral Pediatrics.