Children with ADHD may struggle with poor deep sleep, affecting their daytime functioning. Photo / 123RF
New research on “slow-wave sleep” may have implications for others battling insomnia, including people with anxiety and depression.
Parents and doctors often think about children’s sleep all wrong, says psychologist Jessica Lunsford-Avery. Instead of focusing on quantity of hours, they should pay more attention to quality of rest.
Well-meaning parents and physicians frequently assume a child who is sleepy during the day, or having difficulty thinking or regulating emotions, needs to spend more hours asleep, says Lunsford-Avery, an associate professor of psychiatry and behavioral sciences at Duke University School of Medicine. Yet when the child is suffering from insomnia – trouble getting to sleep or staying asleep, or not feeling rested after sleeping – the answer is more nuanced.
Lunsford-Avery is one of a growing number of researchers studying the importance of a key feature of insomnia: insufficient “slow-wave sleep”. The term refers to the deep, restorative sleep stage in which brain waves slow, breathing decelerates and steadies, muscles relax and waking becomes harder.
Her most recent study links slow-wave differences in children with attention-deficit/hyperactivity disorder to daytime “executive functioning,” which includes problem-solving, planning ahead and controlling impulsivity. But her work has ramifications for others battling insomnia, including people struggling with anxiety and depression.
“The main take-home message is that you shouldn’t assume daytime sleepiness is caused by sheer lack of time asleep and that the answer is to spend more time in bed,” she says. “Often, less time in bed is more helpful.” By restricting, or “consolidating” time in bed, she says, you can increase the drive to sleep more deeply.
In the United States, some 15.5 million adults and 7 million children ages 3 to 17 have been diagnosed with ADHD, and roughly three-quarters of them report problems with sleep. Some scientists speculate that many symptoms attributed to the disorder – including distraction, forgetfulness and moodiness – may stem from a lack of high-quality slumber.
“We still don’t really know if, at least in some cases, ADHD is causing sleeplessness, or sleeplessness is causing ADHD,” says Sandra Kooij, a psychiatrist, researcher and founder and chairwoman of the European Network Adult ADHD, an association of psychiatrists, psychologists and researchers who advocate for more attention and studies of the disorder.
Kooij and her colleagues have shown that people with ADHD tend to have a different circadian rhythm than others, leading many to feel more awake in the evening and more sluggish in the morning.
By some measures, slow-wave sleep is more critical for healthy brains than the more well-known rapid eye movement, or REM, sleep, characterised by vivid dreams. Yet many people, including a significant number of those with typical symptoms of ADHD, don’t get enough of it. The problem often gets worse in adolescence, when parental control of bedtime behaviours breaks down and sleep-postponing temptations, including social media, proliferate.
Using polysomnography – a sleep study measuring brain waves, breathing, oxygen levels, heart rate, muscle activity and more – Lunsford-Avery and her team compared 31 adolescents diagnosed with ADHD with 31 peers who didn’t meet the criteria.
Over three nights, the groups appeared to sleep roughly the same number of hours. But among other differences, those with ADHD spent less time in slow-wave, deeper sleep and performed worse on subsequent cognitive tests. As the researchers expected, the severity of challenges with executive functioning, such as difficulties with focusing attention, memory and decision-making, was closely linked with the deficits in slow-wave sleep.
Paying more attention to sleep quality could be a powerful and sometimes first-line tool in treating ADHD, recent research suggests. Lunsford-Avery says her new study underlines the importance of clinicians making sure they ask all children with symptoms typical of ADHD about their quality of sleep.
“There is a tendency perhaps to think of the executive functioning challenges common in ADHD as part of the ADHD itself,” she says. “This work suggests instead insomnia processes may be the culprit for executive functioning challenges.”
Accordingly, “when clinicians and families notice daytime challenges – whether it’s with cognition, attention or learning – there may be a pull to try to treat what is happening during the day,” Lunsford-Avery says, for example with medication meant to improve daytime attention.
“Those strategies are important and needed,” she adds. “And it’s important to understand that how we function during the day also depends on what happens at night. Routinely asking individuals about their sleep in clinical settings – do they have problems falling and staying asleep, do they feel rested when they wake up – can identify individuals who would benefit from insomnia-focused or other sleep interventions.”
Lunsford-Avery’s findings also point to the value of adopting good sleep hygiene practices early in life. Adolescents suffering reduced slow-wave sleep in her study were more likely to have had sleeping problems as toddlers, according to their caregivers.
In 2004, researchers at Brown University’s medical school and Rhode Island Hospital developed a five-point screening tool for paediatricians. Known by its acronym, Bears, it reminds doctors to ask about bedtime issues, excessive daytime sleepiness, night awakenings, regularity and duration of sleep, and snoring.
Sleep problems are highly variable, but many familiar interventions can help, says Lunsford-Avery.
A 2022 pilot study of 14 adolescents with ADHD and sleep problems found strong evidence of the effectiveness of better management of sleep for ADHD symptoms, including inattentiveness and impulsivity, according to parents. The interventions included several well-known suggestions such as reducing naps and increasing activity during the day.
There’s also evidence to support addressing “sleep inertia,” excessive morning grogginess, which can last from 30 minutes to two hours after waking.
A morning routine known by its acronym Rise-up has been used to treat sleep inertia in people with insomnia.
The initials stand for: Resist the urge to hit the snooze button; increase activity for the first hour after waking; shower or wash your face and hands with cold water; and expose yourself to sunlight, with additional promptings to listen to “upbeat” music and to phone a friend to increase social contact.
Most importantly for kids with ADHD or any others experiencing daytime drowsiness, says Lunsford-Avery, is to make sure to treat the right sleep problem.
Daytime sleepiness also could be caused by sleep apnea or other issues, so it’s essential to consult a healthcare provider. But if it really is insomnia, spending more time in bed, by napping or sleeping late, is not the answer, she says.
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