Use of melatonin for children and adolescents with chronic insomnia attributable to disorders beyond indication: a systematic review, meta-analysis and clinical recommendation.

Background: Melatonin has become a widely used sleeping aid for young individuals currently not included in existing guidelines. The aim was to develop a recommendation on the use of melatonin in children and adolescents aged 2-20 years, with chronic insomnia due to disorders beyond indication.

Methods: We performed a systematic search for guidelines, systematic reviews, and randomised trials (RCTs) in Medline, Embase, Cochrane Library, PsycInfo, Cinahl, Guidelines International Network, Trip Database, Canadian Agency for Drugs and Technologies in Health, American Academy of Sleep Medicine, European Sleep Research Society and Scandinavian Health Authorities databases. A separate search for adverse events was also performed. The latest search for guidelines, systematic reviews, and adverse events was performed on March 17, 2023. The latest search for RCTs was performed on to February 6, 2023. The language was restricted to English, Danish, Norwegian, and Swedish. Eligible participants were children and adolescents (2-20 years of age) with chronic insomnia due to underlying disorders, in whom sleep hygiene practices have been inadequate and melatonin was tested. Studies exclusively on autism spectrum disorders or attention deficit hyperactive disorder were excluded. There were no restrictions on dosage, duration of treatment, time of consumption or release formula. Primary outcomes were quality of sleep, daytime functioning and serious adverse events, assessed at 2-4 weeks post-treatment. Secondary outcomes included total sleep time, sleep latency, awakenings, drowsiness, quality of life, non-serious adverse events, and all-cause dropouts (assessed at 2-4 weeks post-treatment), plus quality of sleep and daytime functioning (assessed at 3-6 months post-treatment). Pooled estimates were calculated using inverse variance random effects model. Statistical heterogeneity was calculated using I statistics. Risk of bias was assessed using Cochrane risk of bias tool. Publication bias was assessed using funnel plots. A multidisciplinary guideline panel constructed the recommendation using Grades of Recommendation, Assessment, Development and Evaluation (GRADE). The certainty of evidence was considered either high, moderate, low or very low depending on the extent of risk of bias, inconsistency, imprecision, indirectness, or publication bias. The evidence-to-decision framework was used to discuss the feasibility and acceptance of the constructed recommendation and its impact on resources and equity. The protocol is registered with the Danish Health Authority.

Findings: We identified 13 RCTs, including 403 patients with a wide range of conditions. Melatonin reduced sleep latency by 14.88 min (95% CI 23.42-6.34, 9 studies, I = 60%) and increased total sleep time by 18.97 min (95% CI 0.37-37.57, 10 studies, I = 57%). The funnel plot for total sleep time showed no apparent indication of publication bias. No other clinical benefits were found. The number of patients experiencing adverse events was not statistically increased however, safety data was scarce. Certainty of evidence was low.

Interpretation: Low certainty evidence supports a moderate effect of melatonin in treating sleep continuity parameters in children and adolescents with chronic insomnia due to primarily medical disorders beyond indication. The off-label use of melatonin for these patients should never be the first choice of treatment, but may be considered by medical specialists with knowledge of the underlying disorder and if non-pharmacological interventions are inadequate. If treatment with melatonin is initiated, adequate follow-up to evaluate treatment effect and adverse events is essential.

Funding: The Danish Health Authority. The Parker Institute, Bispebjerg and Frederiksberg Hospital, supported by the Oak Foundation.