Drug Boosts Performance of Poor Sleepers with ADHD

MONTREAL, Aug. 1 -- For children with attention-deficit hyperactivity disorder who sleep poorly, methylphenidate (Ritalin) helps make them alert when they are awake.

The drug led to improvements in some measures of vigilance for poor sleepers with ADHD who showed deterioration on the Conners' Continuous Performance Test, found Ridha Joober, M.D., and Reut Gruber, Ph.D., of McGill here, and colleagues.

Methylphenidate had no effect on the performance scores of kids with ADHD who had good sleep efficiency, however, the authors reported in the August issue of the journal Sleep.

"Children with low sleep efficiency might improve performance following the administration of methylphenidate as it increases their arousal level to a moderate level, which is presumed to facilitate vigilance performance," the investigators wrote.

They studied 31 boys and six girls from six to 12 who had a confirmed DSM-IV diagnosis of ADHD.

In the double-blind, crossover clinical study, the children's sleep quality was assessed at home with a miniature actigraph placed on a non-dominant wrist. Parents were also asked to keep a nightly sleep log and to complete a sleep questionnaire. The children were divided for the purpose of analysis in to good and poor sleepers.

"Compared to the good sleepers, children in the poor sleep group spent significantly less time sleeping during the night and significantly more time being awake," the authors wrote, "they spent less of the night in immobile sleep and their fragmentation index was higher regardless of medication or placebo [emphasis theirs]."

The authors found that there was a significant interaction between sleep quality and methylphenidate, with poor sleepers having significantly better performance while taking the drug, unlike good sleepers, on the Continuous Performance Test Factor 1, which includes omissions (missed targets), reaction time variability, and reaction time standard error variability and beta.

"These findings agree with previous reports that the performance-enhancing effects of amphetamine were dependent on prior sleep deprivation in normal adults," the authors wrote, adding that "successive increases of arousal beyond the optimal arousal level could lead to impaired performance."

Limitations of the study, the authors noted, included the small sample size, high ratio of boys to girls, precluding a study of the effect of gender, and a lack of objective measures of daytime sleepiness or alertness or information about the children's daytime activities.