Do children with autism spectrum disorders (ASD) get enough sleep? The current body of research suggests that they might not since children with ASD tend to sleep less than typically developing children. A new study from University of Bristol’s Centre for Child and Adolescent Health has used one of the largest and most comprehensive samples to suggest that children with ASD not only have shorter sleep duration than their peers, but also that they wake up more frequently during the night. These sleep patterns could have implications for daytime behavior and the ability to learn.

The researchers drew data for this study from the Avon Longitudinal Study of Parents and Children (ALSPAC). This set has information on the health and development of over 14,000 children born in the years 1991 and 1992 in South West England. Parents in the study were asked about their children’s sleeping habits when the children were at particular developmental intervals: six, 18, 30, 42, 69, 81, 114, and 140 months of age (0.5 years to approximately age 11.5). Parents reported their children’s typical bedtime, when children woke up on weekdays, and how much time children slept during the day.

The research team combined the results of validated questionnaires on social and communication skills (SCDC) and intelligence (WISC-III) from when the children were seven years with the ALSPAC data to produce their results. A total of 86 children had been diagnosed with an autism spectrum disorder by age 11—30 with classic autism, 15 with atypical autism, and 23 with Asperger’s. Ultimately, the analysis compared the 86 children with ASD to over 7,000 neurotypical children.

The results indicated that there was no difference in sleeping patterns between the groups at the age of 30 months. However, the groups diverge after this point. From 30 to 140 months, children with ASD got less sleep—a difference of 17 to 43 minutes—than children without autism. After 140 months, the sleep gap decreased to around 20 minutes or less until the children reached their teens.

Waking up during the night is the primary cause of less sleep among children with ASD who, by the age of 81 months (nearly seven years-old), were waking up three or more times nightly than the neurotypical children. Melatonin, a hormone associated with sleep, may play a role in disrupted sleep patterns; some evidence suggests that people with ASD have impaired melatonin production.

Although decreased sleep time for children certainly has an impact, it is not yet clear what problems it produces. The researchers write that sleep disruption may hamper neuronal development.

This research is published in the journal Archives of Disease in Childhood.

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