【Abstract】 Objective To explore the efficacy of melatonin in treating sleep disorders in children with
autism spectrum disorder (ASD). Methods The literatures related to ASD sleep disorders and melatonin
were searched by computer from the establishment of the database to October 31, 2018. Inclusion criteria:randomized controlled trials (RCT); study subjects are ASD children with sleep disorders; the experimentalgroup was given melatonin and the control group was given a placebo; the outcome indicators weresleep latency, number of awakenings at night, and total sleep time. The Cochrane (version 5.1.0) qualityevaluation criteria was used to evaluate the quality of the literatures. The data were extracted independentlyby two researchers according to the tables. Meta-analysis was performed using RevMan 5.3 software.Heterogeneity analysis was performed using χ2 test, and fixed-effect model or random-effect model wasselected according to whether there was heterogeneity. Results 149 articles were screened out and 8articles were finally included, with a total sample size of 397 cases. The effect of melatonin on the sleeplatency of children with ASD had no significant heterogeneity among the studies (P=0.13, I2
=39%), so the fixed-effect model was selected. The experimental group had got better effect on shortening the sleep latency of ASD children than the control group (SMD=-1.34, 95%CI: -1.61~-1.07, P<0.00001). The effect of melatonin on the number of night awakenings of children with ASD had no significant heterogeneity
among the studies (P=0.41, I2
=2%), so the fixed-effect model was selected. The experimental group had gotbetter effect on reducing the number of night awakenings of ASD children than the control group (SMD=-0.37, 95%CI: -0.60~-0.13, P=0.003). The effect of melatonin on the total sleep time of children with ASDwas analyzed in subgroups according to age (<8 years, ≥ 8 years), and there was significant heterogeneity between studies (P<0.00001, I2
=81%), so the random-effect model was selected. The effect of prolonging the total sleep time of children with ASD in the experimental group was better than that in the control group[<8 years old (SMD=1.06, 95%CI: 0.27~1.85, P=0.008); ≥ 8 years old (SMD=1.37, 95%CI: 0.43~2.32,P=0.004)]. Conclusions Melatonin has a certain effect on alleviating sleep disorders in children with ASD. It canshorten the sleep latency, reduce the number of night awakenings, and prolong the total sleep time.