Faculty of Medicine

Strong association between ADHD and sleep disorders

People who are diagnosed with ADHD report more sleep problems – 15 times more so for certain types of sleep disorders than others without the diagnosis. “These are surprisingly large differences”, says the UiB-researcher behind the study.

Man sleeping

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Attention Deficit Hyperactivity Disorder (ADHD) is connected with hyperactivity, restlessness, and having difficulties concentrating. In addition, many patients report having sleep problems. Exactly how many ADHD patients are suffering from sleep disorders is, however, not very well known. Neither is the nature of the sleep disorders they are experiencing.

Addressing these issues was the goal of Professor Bjørn Bjorvatn from the University of Bergen, and his ADHD-expert colleagues at the KG Jebsen Centre for neuropsychiatric diseases. They asked 268 adults with a known ADHD diagnosis to fill out a questionnaire about sleep, and compared the answers with 202 people who were not diagnosed with ADHD. The differences between the two groups were remarkable:

"83% of patients with ADHD reported sleep problems that last over a month at least once in their life, while only about 36% of the people without ADHD reported the same", says Bjørn Bjorvatn, professor at University of Bergen and also the leader of the Norwegian Competence Center for sleep disorders at Haukeland University Hospital.

Five times more breathing pauses during sleep

The largest difference between the two groups was the prevalence of “restless legs”. Restless legs was reported 15 times more often by ADHD-patients than by people in the control group.

The researchers also asked the participants whether they had been experiencing breathing pauses during sleep, called sleep apnea, or a sudden weakening of muscles caused by emotional reactions, a phenomenon called cataplexy.

"Experiencing restless legs could be related to the other symptoms of the ADHD-diagnosis", says Bjorvatn.

"But this is not the case with sleep apnea or cataplexy", he continues.

The researchers were therefore surprised when they found that ADHD-patients reported sleep apnea five times more often than the control group. Moreover, the ADHD patients slept generally much less than others did. 26.6% of the ADHD-group reported that they spent less than six hours asleep each day, compared to 7.6%in the control group.

Important to study sleep problems of ADHD-patients

Not getting sufficient sleep puts us at risk to develop a long list of diseases, for example diabetes. Research has also shown that sleep deficiency increases the risk to develop obesity and cardiac disease. Anyone who has experienced poor sleep for a few nights knows how this affects the ability to concentrate and makes you feel restless and uneasy. These symptoms are the characteristics of ADHD.

"This study shows that we need to direct our focus specifically towards the sleep problems of ADHD-patients. There are three alternatives", Bjorvatn states:

"First, the patient’s trouble with sleeping might be a symptom of ADHD. Second, the patient may have both, a sleep disorder and ADHD. Third, the patient may suffer primarily from a sleep disorder and develop symptoms that resemble ADHD".

Sleep quality not impaired by ADHD medication

The researchers also wanted to see if the medication most commonly used to treat ADHD, Ritalin, would negatively affect sleep quality. Ritalin is a psychostimulant that increases the neuronal activity in the central nervous system. The researchers were curious whether this stimulation made it more difficult to sleep:

"We didn’t find that ADHD medications affected sleep negatively in any way. In fact, we found the opposite: The patients who use ADHD medicine reported less cataplexy – sudden episodes of muscle weakness - than ADHD patients without medication did. This is an important finding", emphasizes Bjorvatn.

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