Sleep and daytime sleepiness in methylphenidate medicated and un-medicated children with attention-deficit/hyperactivity disorder (ADHD).

OBJECTIVE: Excessive daytime sleepiness due to any cause can result in various symptoms similar to those used for the diagnosis of attention deficit/hyperactivity disorder (ADHD). A common treatment for children diagnosed with ADHD is methylphenidate which is also used to treat excessive daytime sleepiness. This paper reports on a study which compared the perceived levels of daytime sleepiness and prevalence of sleep disorders in medicated and un-medicated children with ADHD.

METHOD: The sample consisted of two matched groups of children who had been formally diagnosed with ADHD. One group (n=12) was taking immediate release methylphenidate twice daily, while the other group (n=11) had never, and were not currently, taking any medication. The two groups, as well as their parents, rated their levels of daytime sleepiness at three points in a single day.

RESULTS: Significantly higher levels of daytime sleepiness were reported by the parents of the un-medicated children between the hours of 13:00 and 15:00, compared to the medicated children. The medicated children became increasingly sleepier from the first to the second measurement in both the morning and afternoon. There was no significant difference in the number of sleep disorders/disruptions reported by the parents of either group.

CONCLUSION: In a group of children with ADHD taking methylphenidate, there was a significant increase in sleepiness a few hours after taking the medication, which may then have a significant impact on their learning. The data also imply that part of the mechanism of action of methylphenidate effects in these children may be by reduction of daytime sleepiness.