Study objectives: Children with attention-deficit/hyperactive disorder (ADHD), in spite of being hyperactive, still benefit from treatment with stimulant medications. We hypothesized that children with ADHD are in fact sleepy during the day, and we sought to test it objectively.
Design: Single blind comparative study
Setting: University medical center
Participants: Thirty-four children with a previous diagnosis of ADHD (mean age +/- SD, 12.4 +/- 4.6 years) and 32 matched controls (mean age, 12.0 +/- 3.6 years).
Measurements: All participants underwent a full-night polysomnographic study followed by a multiple sleep latency test (MSLT).
Results: Sleep latency, total sleep time, and sleep efficiency were comparable between the groups, yet children with ADHD were significantly sleepier during the day than those in the control group (mean MSLT score of 21.9 +/- 5.5 minutes versus 27.9 +/- 2.0 minutes, P < .005). Of the children with ADHD, 17 (50%) had signs of sleep-disordered breathing, compared with 7 of the control group (22%, P < .05). Five of the ADHD group had periodic limb movements during sleep (15%) versus none in the control group. Children without sleep-disordered breathing or periodic limb movements during sleep had the lowest nocturnal sleep efficiency and total sleep time.
Conclusions: We conclude that children with ADHD demonstrate objective daytime somnolence, which may explain the beneficial effects of treatment with stimulant medications. Primary sleep disorders, especially sleep-disordered breathing and periodic limb movement disorder, should be looked for in children with ADHD.