REVIEW OF: Wei S et al, Sleep Medicine 2020;68:1–8

Sleep-onset insomnia, characterized by difficulty falling asleep and daytime fatigue, is a common problem among youth. While sleep hygiene is the first step, families often have trouble implementing such measures, which include regular wake-up times, daily exercise, shutting down screens in the evening, and reserving the bed just for sleep. At CCPR, we advise caution before using marketed sleep medication (Editor’s note: For a full discussion, see Carlat’s 2018 Child Medication Fact Book for Psychiatric Practice). One potentially safer option is melatonin. But is exogenous use of this hormone effective? Is it safe? This meta-analysis looked at the safety and efficacy of melatonin in randomized placebo-controlled studies.

The authors of the meta-analysis examined 550 studies and found that only seven met their criteria for methodology. In these studies, a total of 387 youth with sleep-onset insomnia were enrolled in placebo-controlled trials. Most subjects were children (94.6%), with a mean age of 9 years. All studies used immediate-release melatonin tablets at doses of 1–6 mg/day for 1–4 weeks.

Melatonin was often effective in very low doses. Sleep onset time, the primary outcome for efficacy, generally came over a half hour earlier with use of melatonin compared to placebo. Total sleep time was increased by about 20 minutes.

Side effects included fatigue, headache, gastrointestinal upset, and depressed mood. Specific percentages of these were not reported; however, symptoms were mild to moderate, with little difference in dropout rates between melatonin and placebo. One patient developed generalized seizures 4 months after using melatonin, and there were mixed reports of both more and fewer seizures in the studies that were not included in the meta-analysis. The authors note possible concerns in long-term use of melatonin, with particular concerns about reproductive function and the course of epilepsy.

CCPR’s Take
This study suggests a modest clinical utility for short-term use of melatonin in children and adolescents struggling with sleep-onset insomnia, perhaps starting at 1 mg. Although generally safe, melatonin may lower the seizure threshold and should be used with caution in patients with seizure disorders. As a note, melatonin tends to work better given 90–120 minutes before desired sleep onset, and good sleep hygiene always comes first.