With a glance
- Teenagers who slept less than nine hours a day had differences in brain structure and more problems with mood and thinking than those who got enough sleep.
- The findings suggest that sleep interventions may be needed to help improve mental and behavioral health during preadolescence and beyond.
Scientists have long recognized that getting enough sleep in childhood can benefit brain development. However, the underlying brain mechanisms are not well understood. And although experts say children ages 6 to 12 should get at least nine hours of sleep each day, it’s unclear how less sleep might affect a child’s brain.
To get some answers, a research team led by Dr. Ze Wang of the University of Maryland set out to see how sleep deprivation affects brain structure and other outcomes. They drew on data collected in the NIH’s ongoing Adolescent Brain Cognitive Development (ABCD) study. ABCD has enrolled nearly 12,000 volunteers aged 9 or 10 from research sites across the country. The participants’ health, brain structure and function, and other factors will be tracked for a decade as they transition from adolescence to young adulthood.
Researchers identified more than 4,000 ABCD participants aged 9 or 10 who typically got nine or more hours of sleep per day, according to their parents. This group was compared to a similar number of children of the same age who typically slept less than the recommended nine hours. The research team carefully matched the two groups based on some key factors that could confound the study results. These factors include gender, household income, body mass index, and puberty status. Participants were assessed and followed over a period of two years. The results appeared in Lancet Child and Adolescent Health on July 29, 2022
The researchers found that children in the sleep-deprived group at the start of the study had more mental health and behavioral problems than those who got enough sleep. These include impulsivity, stress, depression, anxiety, aggressive behavior and thinking problems. Children with insufficient sleep also had impaired cognitive functions such as decision-making, conflict resolution, working memory and learning. Differences between groups persisted at the two-year follow-up.
Brain imaging at the start of the study and two years later showed differences in brain structure and function in the sleep-deprived group compared to the sleep-deprived group. The findings show that sleep affects learning and behavior through specific brain changes.
“Children who had insufficient sleep – less than nine hours a night – at the start of the study had less gray matter or less volume in certain areas of the brain responsible for attention, memory and inhibitory control, compared to those with healthy sleep habits,” Wang explains. “These differences persisted after two years, an alarming finding that suggests long-term harm to those who don’t get enough sleep.”
As the ABCD study continues, the researchers note that there will be opportunities to add more follow-up measurements and build on their results. “Further studies are needed to confirm our findings and see if any interventions can improve sleep habits and reverse the neurological deficits,” adds Wang.
– by Vicki Conti
Financing: NIH’s National Institute on Aging (NIA), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Center for Advancing Translational Sciences (NCATS), and National Institute on Drug Abuse (NIDA).