Effect of melatonin on sleep, behavior, and cognition in ADHD and chronic sleep-onset insomnia

Objective: To investigate the effect of melatonin treatment on sleep, behavior, cognition, and quality of life in children with attention-deficit/hyperactivity disorder (ADHD) and chronic sleep onset insomnia. Method: A total of 105 medication-free children, ages 6 to 12 years, with rigorously diagnosed ADHD and chronic sleep onset insomnia participated in a randomized, double-blind, placebo-controlled trial using 3 or 6 mg melatonin (depending on body weight), or placebo for 4 weeks. Primary outcome parameters were actigraphy-derived sleep onset, total time asleep, and salivary dim light melatonin onset. Results: Sleep onset advanced by 26.9 +/- 47.8 minutes with melatonin and delayed by 10.5 +/- 37.4 minutes with placebo (p < .0001). There was an advance in dim light melatonin onset of 44.4 +/- 67.9 minutes in melatonin and a delay of 12.8 +/- 60.0 minutes in placebo (p < .0001). Total time asleep increased with melatonin (19.8 +/- 61.9 minutes) as compared to placebo (-13.6 +/- 50.6 minutes; p = .01). There was no significant effect on behavior, cognition, and quality of life, and significant adverse events did not occur. Conclusion: Melatonin advanced circadian rhythms of sleep-wake and endogenous melatonin and enhanced total time asleep in children with ADHD and chronic sleep onset insomnia; however, no effect was found on problem behavior, cognitive performance, or quality of life. J. Am. Acad. Child Adolesc. Psychiatry, 2007;46(2):233-241.