Sleep in adults with attention deficit hyperactivity disorder (ADHD) before and during treatment with methylphenidate: a controlled polysomnographic study.

ATTENTION DEFICIT HYPERACTIVITY DISORDER (ADHD) WAS LONG CONSIDERED AS A DISORDER PREVALENT ONLY IN CHILDREN AND ADOLESCENTS. MORE recently, however, ADHD has been conceptualized as a lifelong disorder prevalent in most afflicted individuals from childhood to adulthood. Data from independent longitudinal studies clearly provide evidence of a continuation of the disorder into adulthood in up to 60% of afflicted children.1,2 Additionally, the results of the National Comorbidity Survey Replication show a prevalence of ADHD among the general adult U.S. population to be 4.4%3. Due to the clinical observation that sleep problems are common in children with ADHD and the former inclusion of excessive movements during sleep in the diagnostic criteria according to DSM-III,4 sleep quality and disturbances have been the topic of numerous studies carried out in children with ADHD (for review see reference 5). Studies assessing subjective sleep disturbances consistently revealed more problems with falling asleep along with longer sleep latencies, more bedtime struggles, nocturnal awakenings, restless sleep, daytime sleepiness, and a higher rate of enuresis compared to control children without ADHD, indicating an approximately fivefold increase in the rate of sleep problems in children with ADHD.5,6 Although conflicting in some aspects, investigations of objective sleep parameters have quite consistently shown reduced REM sleep, more nocturnal movements, increased frequency of periodic limb movements (PLMS) and PLMS-associated arousal as well as elevated daytime somnolence in children with ADHD when compared to controls.7–11 While sleep problems are also common in the clinical practice of adult ADHD, studies examining sleep in adults with ADHD are relatively sparse. To the best of our knowledge there are 3 questionnaire studies (n = 219, n = 141, n = 120), one controlled actigraphic (n = 8) and one controlled polysomnographic (n = 20) study assessing sleep parameters in adults with ADHD.12–17 As a common finding the cited questionnaire studies consistently report high rates of sleep problems in up to 83% of the assessed adults, including sleep onset problems, restless sleep, and insufficient restorative value of sleep.12–14 Both studies assessing objective sleep parameters report significantly more nocturnal periodic leg movements and an elevated movement level during sleep, whereas no differences in sleep architecture or efficiency were found between patients with ADHD and healthy controls.15,16 While the influence of stimulants, the most widely used pharmacological treatment for ADHD, on sleep parameters has been extensively studied in children18–26 there is currently only one small actigraphic study assessing the effect of stimulant medication on sleep patterns and quality in adults with ADHD.15 The aim of our study was to investigate the following topics. As the results of the only available polysomnographic study on sleep in adults with ADHD differ in some aspects from data obtained in polysomnographic studies in children we wanted to assess objective (polysomnographic) and subjective (self-rated sleep questionnaires) sleep parameters in an independent sample of adults with ADHD. As the majority of studies in children with ADHD found a reduction of REM sleep, which was not the case in the polysomnographic study in adults with ADHD,16 we were especially interested to see, if our study would confirm this finding. We expected to observe a reduction in the percentage of REM sleep in adult patients as previously been described in children with ADHD. As there is no polysomnographic or corresponding subjective data on the influence of stimulant medication on sleep parameters in adults with ADHD, we wanted to assess the impact of treatment with methylphenidate on objective and subjective sleep parameters. According to the preliminary results of the actigraphic study we expected a reduction of nocturnal movement level and improved subjective sleep quality.