The journal Sleep Medicine Reviews recently published the results of a systematic review and meta-analysis examining melatonin supplementation among children with neuropsychiatric and neurodevelopmental conditions, specifically to assess the variables that may optimally influence sleep, including dose, timing, and duration of treatment. Twenty-one studies (which followed PRISMA guidelines) were included, with differences compared between placebo and melatonin supplementation among children with a variety of diagnoses, such as ADHD, autism spectrum disorder, and other conditions often complicated by impaired sleep.
Overall, melatonin significantly improved total sleep time, increased sleep efficiency, and reduced sleep onset latency (the time it takes to fall asleep initially), but did not significantly improve wake after sleep onset (time spent awake after falling asleep). The optimal dose of melatonin was found to be between 2 and 4 mg, with the optimal timing found to be melatonin given 3 hours before bedtime. Also, a longer duration of melatonin supplementation was associated with increased total sleep time and sleep efficiency, suggesting more than just short-term gains.
These findings parallel results of a systematic review and meta-analysis of 26 randomized and controlled trials published in 2024, which included healthy adults and those with insomnia. In contrast to the often-recommended dosing of “1/2 an hour before bedtime,” this meta-analysis also found that the optimal timing is more likely to be 3 hours before bedtime. They also found that instead of the most frequently observed dose of 2 mg in clinical practice, increasing the dose up to 4 mg was associated with the largest improvements in promoting sleep.