The ADHD Factor
Sleep lab studies suggest links between ADHD and sleep problems. For example, kids with ADHD tend to have high rates of medically caused sleep disorders like restless leg syndrome (RLS), characterized by prickly, painful, twitching sensations when legs remain still, and PLMD, in which leg muscles repeatedly contract at night, temporarily waking the child. One study from the University of Illinois at Urbana-Champaign looked at 69 children diagnosed with ADHD and found that 26% suffered from PLMD, a disorder that's rare in the rest of the population.
In another study, conducted by Ronald D. Chervin, M.D., director of the University of Michigan Sleep Disorders Center in Ann Arbor, it was found that habitual snoring, a symptom of OSAS, occurred in 33% of kids ages 2 to 18 diagnosed with ADHD, compared to 9% of a control group. "Sleep disorders won't explain the majority of behavioral problems in children, but even if they affect a small fraction of hyperactive kids, it's still a lot of kids," he says.
Yet sleep habits are not typically considered when kids are assessed for behavioral or learning issues. "Absolutely every child who's being evaluated for academic problems, learning problems, behavioral problems, or ADHD should be screened for sleep issues," says Dr. Owens.
Could You Spot a Sleep Disorder?
As the research from Tel Aviv shows, parents are often unsure of what constitutes a sleep problem. Indeed, most parents don't consider it worrisome if their baby wakes up and cries in the middle of the night, nor if their child has an overly lengthy bedtime ritual and the parents have to be present while the child falls asleep, explains Thomas F. Anders, M.D., professor of psychiatry at the University of California at Davis. But unless that child is a newborn, those issues are in fact cause for concern. "Parents tend to see their child's behavior as routine because they've adapted to it, or they may be unwilling to label the behavior as problematic," says Dr. Anders. And as children reach school age, parents may simply be left in the dark about their kids' sleep problems because older children are less likely to alert their parents every time they wake up in the middle of the night.