Subjective and objective assessments of sleep problems in children with attention deficit/hyperactivity disorder and the effects of methylphenidate treatment

Background: to investigate the sleep problems in children with different ADHD presentations and effects of methylphenidate (MPH) on the sleep problems of children with ADHD by both subjective and objective measurements. Methods: 71 children with ADHD and 30 controls were included. 35 had ADHD with predominantly inattentive presentation (ADHD-I) and 36 with predominantly hyperactive/impulsive or combined presentation (ADHD-C). We used the pediatric sleep questionnaire (PSQ) and a nocturnal polysomnography (PSG) to assess the sleep problems in children with ADHD before and 6 months after being treated with methylphenidate (0.3-0.7 mg/kg/dose). Results: PSG showed significantly higher apnea-hypopnea index and hypopnea counts, and lower slow-wave sleep percentage in children with ADHD. The results of PSQ reported by parents showed significantly higher rates of delay initiation of sleep, sleep onset latency, sleep fragment, daytime sleepiness, enuresis, bruxism, nightmares, periodic limb movement disorder (PLMD), and snoring in children with ADHD compared to normal controls. Comparisons of ADHD presentations revealed no significant difference between ADHD-I and ADHD-C by either PSG or PSQ measurements. After 6-month MPH treatment, the PSG showed significantly increased total sleep time and reduced periodic limb movement index (PLMI). The PSQ indicated significant reduction in bruxism and snoring in ADHD-I, as well as nightmares in ADHD-C, and both subgroups showed significant reduction in PLMD. Conclusion: subjective and objective approaches produced inconsistent findings regarding the sleep problems in children with ADHD. Besides, MPH didn't worsen the sleep problems in children with ADHD.