Robyn Boyle, RPh, for MDLinx | November 20, 2017
Adults with attention-deficit/hyperactivity disorder (ADHD) report a higher incidence of several different sleep problems such as self-reported restless legs and cataplexy, compared to controls without ADHD, according to results of a study published in Frontiers in Psychology.
“Our study demonstrated that a variety of specific self-reported sleep-related problems, including restless legs and cataplexy, were very common among adults with clinically ascertained ADHD. All the examined self-reported sleep variables were significantly associated with having ADHD, even when including age and sex as co-variates,” wrote the study’s authors, led by Bjorn Bjorvatn, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
Furthermore, current use of ADHD medication was associated with less cataplexy, and patients with the inattentive subtype (IA) reported less restless legs and better sleep quality compared with hyperactive/impulsive (HI) or combined subtypes.
The cross-sectional study is part of an ongoing Norwegian adult ADHD project, and researchers included 268 adults with ADHD and 202 randomly selected controls. To reduce selection bias, no formal exclusion criteria were used.
Sleep problems were self-reported by patients, using some of the questions from The Global Sleep Assessment Questionnaire (GSAQ).
Clinician-reported classification into ADHD subtypes was available for 50.4% of patients (n=135; subtype breakdown: 54 IA; 6 HI; 75 combined) as well information on medication use (n=94; 69 methylphenidate, 12 amphetamines, 3 atomoxetine, 7 combination, 3 unknown).
The difference for reported sleep problems between ADHD patients and controls was dramatic. A full 82.6% of ADHD patients experienced sleep problems lasting more than 1 month compared to 36.5% of controls (P < 0.001). ADHD patients also reported more problems with other characteristics of sleep than controls including use of hypnotics (61.4% vs 20.2%, respectively; P < 0.0001) and sleep duration less than 6 hours (26.6% vs 7.6%; P < 0.0001).
The researchers also found strong associations between ADHD and more specific sleep disorders such as excessive daytime sleepiness, cataplexy, loud snoring, breathing pauses during sleep, restless legs, and periodic limb movement during sleep.
Patients currently using medication were more likely, however, to report less cataplexy compared with those not using medication. Further, in comparing ADHD subtypes, researchers found that the IA subtype was associated with less restless legs and better sleep quality compared to HI or combined subtype.
Investigators noted that the study had some limitations. Controls were recruited without exclusion criteria so it is possible that some controls had ADHD or symptoms of ADHD, and the severity of ADHD was not reported, making use of treatment difficult to evaluate.
In addition, cataplexy was reported more than expected, and researchers recommended careful interpretation of the findings, as some participants may have misinterpreted the question, although both groups responded to the same wording.
The authors concluded: “…adult ADHD patients reported considerably more of both general sleep impairment and specific sleep-related problems, including self-reported restless legs and cataplexy, compared to a representative control group.”
Furthermore, current use of ADHD medication was associated with less cataplexy and the IA subtype was associated with fewer sleep problems.
“Taken together, these findings underline the importance of screening for sleep disorders as part of the diagnostic assessment and treatment of ADHD,” they concluded.
Bjorvatn B, Brevik EJ, Lundervold AJ, et al. Adults with attention deficit hyperactivity disorder report high symptom levels of troubled sleep, restless legs, and cataplexy. Front Psychol. 2017;8:1621.