There are more than 70 different types of sleep disorders, Harvard experts say, and up to half of all children diagnosed with ADHD suffer from at least one of them. Sleep disorders are also commonly reported in adults with ADHD. Brain researchers are working hard to find out why.

Up to half of all children diagnosed with ADHD have trouble falling asleep, staying asleep or sleeping peacefully. Up to a quarter have sleep-related breathing problems while even more have movement problems, such as restless legs syndrome, that affect their quality of sleep. Although most clinical studies of sleep disorders and ADHD have been performed on children, adults with ADHD very often report sleep problems as well.

Unraveling the connection between ADHD and sleep disorders is proving to be a complicated task. ADHD can take the form of hyperactive ADHD or inattentive ADHD, and just as these different types of ADHD exhibit v arying symptoms, different types of sleep disorders manifest themselves in unique ways. Some people with ADHD take medication for their symptoms that may affect their sleep, and some do not. At the same time, some people take medication for sleep disorders that may affect ADHD symptoms, while others do not.

Researchers who are trying to figure out which sleep disorders are associated with which type of ADHD, and why, must first untangle a wide array of confounding factors and overlapping symptoms. To confuse things even more, some of the symptoms of sleep disorders and sleep deprivation are very similar to the symptoms of ADHD.

In the past, sleep disorders in people with ADHD have often been associated the psychostimulant medications commonly used to treat ADHD. Now, however, sleep apnea, restless leg syndrome, and other problems that are disruptive to sleep are being recognized as separate disorders that commonly occur with ADHD, not necessarily as a result of medication. At the same time, scientists suspect the answer can be found along the same neural pathway, because these conditions are all linked to imbalances of dopamine, the brain chemical that helps controls movement, emotional response, and sensations of pleasure and pain.

A small study of 22 non-medicated adults diagnosed with ADHD, published in the September 2009 issue of the online version of Journal of Attention Disorders, found that sleep problems such as an inability to stay asleep and sleep quality are associated with hyperactive-impulsive ADHD but not with those people who have inattentive ADHD.

As  Denver psychiatrist William Dodson, M.D. points out, in order for a child to be diagnosed with ADHD, the American Psychiatric Association requires all symptoms to be exhibited by the age of seven. Yet sleep disturbances rarely appear until around the age of 12 1/2. As a result, only recently, as more adults have been diagnosed with ADHD and more studies have focused on adults, have researchers been able to link ADHD directly to sleep disorders and start to sort out the connection so that better treatment strategies can be recommended.

Sources:

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Mahajan, N, Hong, N, Wigal, T, and Gehricke, JG. "Hyperactive Impulsive Symptoms Associated with Self-Reported Sleep Quality in Non-Medicated Adults with ADHD." Journal of Attention Disorders. 18 Sept 2009. Web. 11 Aug 2010..
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Gavin, K. "Sleep Disorders May be Linked to Faulty Brain Chemistry, University of Michigan Researchers Report." University of Michigan. 7 July 2003 Web. 11 Aug 2010.
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Volkow, ND, Wang, GJ, Kollin, SH, et al. "Evalutating Dopamine Reward Pathway in  ADHD: Clinical Implications. Journal of the American Medical Association. Aug 2009 302(10: 1084-1091. 12 March 2010. Web. 11 Aug 2010.
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Wagner, ML, Walters, AS, Fisher BC, "Symptoms of Attention-Deficit/Hyperactivity Disorder in Adults with Restless Leg Syndrome." Sleep 27(8): 1499-504. Dec 2004. Web. 11 Aug. 2010.
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