It’s well known that students find it harder to focus if they haven’t slept the night before, but new research suggests sleep problems and attention-deficit disorders may be linked in ways that escalate both problems.
While there is not evidence yet on whether attention deficits cause or are caused by sleep problems, or whether both are linked in some other way, “We know that poor sleep and ADHD frequently co-occur; often sleepiness aggravates ADHD symptoms and ADHD symptoms make it difficult to go to bed, fall asleep, and sleep well, said Karen Sampson Hoffman, a spokeswoman for the National Resource Center on ADHD. “There does seem to be a relationship between the two difficulties.”
Now researchers are looking for new ways to improve students’ attention deficits through more sleep-related treatments, such as light therapy and better bedtime routines.
The studies are part of a growing body of evidence of connections between attention deficits and sleep problems that could also intensify debates in the education field over school schedules and extracurricular activities that can throw off students’ sleep cycles.
As many as 30 percent of children with attention deficit disorders also have significant sleep problems, including insomnia, delayed sleep, and daytime drowsiness, prior research has found.
Katherine Peppers, a pediatric nurse and mental health specialist in Raleigh, N.C., sees it in her own practice. On average, she said, the students with attention deficits she works with take nearly twice as long to fall asleep as other children their age.
“The average child falls asleep in 20 to 26 minutes; kids with ADHD may not fall asleep for 52 to 55 minutes,” Peppers said.
“During that time, they’re not just lying in bed quietly; they’re up and down, they’re petitioning for a snack and water ... so it can be really challenging for parents with school-age children to get them out of bed the next morning,” she said.
Yet it has proven difficult for school officials or medical practitioners to identify sleep disorders related to attention deficits, because so many U.S. students already get too little sleep.
The National Sleep Foundation recommends school-age children get nine to 11 hours of sleep each night, and that teenagers get eight to 10 hours of sleep. The group found that American students—particularly teenagers—regularly fall short of those goals.
Data from two global studies—the Trends in International Mathematics and Science Study and the Progress in International Reading Literacy Study—found 70 percent of U.S. teachers reported 4th and 8th grade students’ sleepiness limits instruction “some” or “a lot” in math and science, far above the global range of 48 percent to 56 percent.
“What we know at this point is sleep deprivation can look very much like ADHD, and it’s very difficult to get an accurate read when 70 percent of our kids [overall] are sleep deprived,” Peppers said.
In a gathering of the European College of Neuropsychopharmacology earlier this month, J.J. Sandra Kooij, the founder of the Attention Deficit Hyperactivity Disorder Network, argued that while not all attention disorders are associated with sleep problems, disruptions to circadian sleep cycles are an “important element” contributing to students’ symptoms.
“Based on existing evidence, it looks very much like ADHD and circadian problems are intertwined,” said Kooij, an associate psychiatry professor at Vrije Universite Medical Center in Amsterdam.
The circadian cycle is one of two interconnected systems that govern sleep. While everyone gets sleepier the longer they have been awake, they also become sleepy in response to changing light during the day. Early-morning, short-wavelength “blue” light increases alertness, while longer-wavelength “red” light that increases near dusk triggers the brain to release the sleep-promoting chemical melatonin and a drop in body temperature.
Yet Kooij and her colleagues have found on average 1.5-hour delays in the release of melatonin and lower body temperature before sleep in 75 percent of people with attention-deficit hyperactivity disorder.
A 2015 analysis by John Herman, a sleep specialist at the University of Texas Southwestern Medical Center in Dallas, found mixed evidence of whether ADHD is caused by delayed or disrupted sleep, but did find evidence that melatonin improved sleep problems for children with ADHD.
Improving Sleep Habits
In a pilot study last year, Peppers and researchers from Duke University and the University of North Carolina-Chapel Hill found that children ages 5 to 11 with ADHD showed improved symptoms after a 20-week program in which they and their parents learned about the importance of sleep and how to create a good routine before bed.
The hardest change for most families? “No screen—no phone, no tablet, no laptop, none of that—for two hours before bed,” Peppers said.
For students with attention deficits, who are more than twice as likely to experience difficulty with and take longer to complete homework, that’s a heavy lift.
In research on adolescent students with ADHD, Joshua Langberg, a co-director of Virginia Commonwealth University’s Center for ADHD Research, Education, and Service found middle and high school students with attention deficits are most likely to experience homework problems in the early evening, and, “considering the frequency with which adolescents with ADHD experience significant homework problems, homework management and completion difficulties are likely significant risk factors” for their sleep problems.
Peppers advised schools to encourage families of students with attention deficits to schedule homework time before dinner, to separate it from the bedtime routine, and use screen-dimming tools if students have to use computers after sunset.
“We really focus on the importance of helping the child transition from day to evening,” she said.
Educators evaluating students with attention deficits should also consider recommending that parents reach out to a pediatrician to determine if physical sleep problems are exacerbating students’ symptoms, Peppers said.
For example, Herman also found that children with ADHD often have mild apnea—a condition in which a child stops breathing for short periods during sleep—and that surgically treating the apnea improved children’s attention deficits more than using stimulants, which themselves can disrupt sleep.
