Children who get the fewest hours of sleep are at the highest risk of developing mental health issues later, including ADHD, anxiety and depression, suggest a new study.
"If we make sure our children get enough sleep, it can help protect them from mental health problems," said Bror M. Ranum, a PhD candidate at the Norwegian University of Science and Technology's (NTNU) Department of Psychology.
"We're seeing an association between sleep duration and risk of symptoms of emotional and behavioural disorders," said Ranum, first author of a new article on children, sleep and risk of mental health disorders.
In a study conducted at the Norwegian University of Science and Technology, of almost 800 children, it is found that both girls and boys who get less sleep are at greater risk for future emotional problems, Medical Daily reported.
For the study, children's sleep was measured with motion sensors every night for a week. The researchers conducted clinical interviews to measure mental health difficulties. These procedures were repeated several times every two years.
This is a long-term study that has examined nearly a thousand children when they were 4, 6, 8, 10, 12 and 14 years old.
"If you find that your child seems to be under the weather and can't concentrate, or you notice their mood fluctuate more than normal, then you may want to help them get more sleep," Ranum says. He says it is difficult to give advice that fits for all families and all children. But having a consistent wake-up time in the morning is perhaps the most important way to develop healthy sleep habits.
The research group has also investigated how many people get too little sleep, and whether or not too little sleep tends to persist throughout childhood. Very few six-year-olds (1.1%) slept less than 7 hours, which is below the internationally recommended sleep guidelines for this age group.
But as the children got older, the number who were not getting enough sleep gradually increased (at age 8: 3.9%; age 10: 4.2% and age 12: 13.6%). Children who were getting too little sleep when they were 6 years old did not necessarily suffer from a lack of sleep when they got older, with most of them meeting the recommended sleep duration. But if insufficient sleep started later, at age 10 for example, the habit tended to persist. Fewer of these children outgrew their insufficient sleep pattern as they got older.
The study findings suggest that parents don't need to worry unnecessarily. Some adjustments to sleep routines may be advisable if your child is affected by lack of sleep.
The UK's Sleep Council recommends that toddlers need around 12 hours of sleep a night; children aged three to six – 10-12 hours; seven-12 years olds – 10-11 hours; and teenagers – around eight to nine hours.