Could your kid's ADHD be linked to a sleep problem?

Some kids with attention deficit hyperactivity disorder (ADHD) might have trouble focusing on their homework, while others might zone out in class. Others still might have trouble waiting their turn to play with a toy. The one thing they're all likely to have in common? They don't get the quality or quantity of sleep they need.

New research has found that about 75 percent of kids and adults with ADHD have sleep problems. ADHD is a behavioural disorder characterized by inattention, hyperactivity and impulsivity, but according to a new theory, it may be connected with sleep issues. Sandra Kooij, associate professor of psychiatry at VU University Medical Center Amsterdam and founder of the European Network Adult ADHD, presented the theory that sleep problems and ADHD are two sides to the same coin. Through her two decades of experience working with adults who suffer from ADHD, she began to notice that the majority of them consistently fell asleep late and did not get enough sleep. When she measured melatonin levels, she found that the naturally occurring sleep hormone was delayed by about an hour and a half in three-quarters of patients.

Her colleague, who studies ADHD in children, found a similar trend in kids. Overall, kids and adults who have ADHD are likely to regularly fall asleep very late, suffer from sleep apnea or experience restless leg syndrome. This doesn't mean the sleep issues are necessarily the cause of the ADHD—rather, the two are interconnected.

"My hypothesis is that ADHD is a circadian disturbance, with sleep problems at night and behaviour issues during the day," says Kooij. It's true that poor sleep can lead to difficulty paying attention—after all, sleep sets the clock that controls many of our bodily functions, from appetite to cell renewal. "When you are not in sync, the body feels jet lagged," says Kooij. On the other hand, ADHD behaviours—say, having difficulty staying on schedule or winding down—can also make getting enough sleep a challenge.

But taking steps to improve sleep could help reduce behavioural symptoms during the day. Kooij says some people have been using a combination of melatonin supplements in the evening and light therapy in the morning to shift their circadian rhythms back on schedule. If you have a kid with ADHD, Kooij suggests talking to your paediatrician about giving them melatonin. "Sleep is highly important and we need enough hours of sleep. But it’s not easy for parents of kids with ADHD," she says.

Another problem is that kids with ADHD might be especially likely to watch TV or play games while they're waiting for their brains to shut off at night, and the blue light that's emitted from TVs, smartphones and tablets delays the body's release of melatonin. Because of this, Kooij suggests all parents limit screen time before bed.

Developing a healthier bedtime routine can be a struggle at first, but if you can help kids with ADHD catch more z's at night, you just might be able to help them feel better throughout the day.

Read more: The problem with ADHD 6 things to know about melatonin for kids