We conducted an umbrella review to summarize all available systematic reviews and meta-analyses investigating the efficacy of melatonin and melatonin agonists in primary and comorbid insomnia disorders. Two independent reviewers conducted a search of Pubmed, EMBASE, Cochrane Database of Systematic Reviews, Google Scholar, PROSPERO and grey literature from inception to July 2018. Methodological quality was assessed using the revised Assessment of Multiple Systematic Reviews Instrument. Eighteen studies were found, with methodological quality ranging from Moderate to Critically Low. Of the twelve papers evaluating melatonin, there is statistically significant improvement in sleep latency and total sleep time, with a lack of consensus on whether these are clinically meaningful. Similar results are observed across the three reviews on ramelteon. The evidence for other melatonin agonists is sparse. We conclude that existing evidence is limited by disparate methodological quality of the papers, as well as a lack of consensus regarding the type, definition and interpretation of outcome measures in the evaluation of efficacy for insomnia.

中文翻译：

---

褪黑素和褪黑素激动剂在失眠症中的功效-综述。

我们进行了总括性综述，总结了所有可用的系统评价和荟萃分析，研究了褪黑激素和褪黑激素激动剂在原发性和合并症失眠症中的功效。从成立到2018年7月，两名独立审稿人对Pubmed，EMBASE，Cochrane系统评价数据库，Google Scholar，PROSPERO和灰色文献进行了搜索。方法质量通过修订后的《多重系统评价工具评估》进行评估。发现了十八项研究，方法学质量从中度到严重偏低。在评估褪黑激素的12篇论文中，睡眠潜伏期和总睡眠时间有统计学上的显着改善，但对于是否具有临床意义尚无共识。在有关ramelteon的三个评论中观察到了相似的结果。其他褪黑激素激动剂的证据很少。我们得出的结论是，现有证据受限于论文的不同方法学质量，以及在评估失眠疗效时对结果指标的类型，定义和解释缺乏共识。