A study from Guangzhou, China, found that autistic children under 6 had later sleep schedules, slightly less total sleep and more frequent night waking than typically developing children of the same age.
The findings describe differences between groups; they do not show that autism caused the sleep patterns or that sleep difficulties came first. The research was cross-sectional and case-control, meaning the children’s sleep was assessed at one point rather than followed over time.
Later bedtimes and shorter sleep
The study included 246 autistic children recruited through a hospital and 246 typically developing children recruited from local kindergartens. The groups were matched one-to-one by age. The autistic children had an average age of 3.6 years, compared with 3.8 years in the comparison group.
On average weekday nights, autistic children fell asleep at about 10:04 p.m. and woke at 7:42 a.m. The corresponding times for typically developing children were about 9:41 p.m. and 7:16 a.m.
Before adjustment, average weekday sleep was 9.3 hours for autistic children and 9.6 hours for the comparison group. After researchers accounted for child age, sex, gestational age, delivery method, birth weight, maternal age and maternal education, autistic children slept about 16 minutes less on weekdays and 17 minutes less on weekends.
The adjusted differences also indicated that autistic children went to sleep about 33 minutes later and woke about 25 minutes later on weekdays. The fact sheet describes the average sleep differences as modest, generally around 15 to 35 minutes.
Night waking was more common
Parents reported that 32.6% of autistic children woke more than once a week, compared with 18.1% of typically developing children. Waking five to seven times a week was reported for 19.8% of autistic children and 7.2% of comparison children.
After adjustment, the odds of frequent night waking were 2.31 times higher among autistic children. The 95% confidence interval was 1.38 to 3.87.
When a waking occurred, its reported duration was about 27 minutes among autistic children and 23 minutes among comparison children. That difference was not statistically significant.
Weekend patterns did not show more social jetlag
Both groups shifted their sleep later on weekends by a similar amount. Weekend sleep began at around 10 p.m. for both groups. Autistic children woke at about 8:19 a.m., compared with 7:44 a.m. for typically developing children, and slept 9.4 versus 9.7 hours before adjustment.
Social jetlag—the difference between weekday and weekend sleep timing—was just under half an hour in both groups: 0.45 hours for autistic children and 0.47 hours for the comparison group. The researchers suggested that schedules for preschool children may be flexible enough for weekday and weekend sleep to look relatively similar.
Even so, autistic children had greater weekday bedtime variability. The standard deviation was about 2.5 hours, compared with about 40 minutes in the comparison group. Their sleep midpoint was also later, and an adjusted chronotype score that accounted for weekend catch-up sleep was about 46 minutes later.
How the study measured sleep
Sleep was assessed during a face-to-face parent interview using the Chinese version of the Children’s Sleep Habits Questionnaire. The study did not use wrist-based activity monitors, known as actigraphy, or an overnight sleep study such as polysomnography.
The autistic children had been diagnosed by two specialists using standard clinical criteria, the ADOS observation and the ADI-R parent interview. About 86% of the autistic children were boys, compared with 64% of the comparison group. Mothers of autistic children were also less likely to hold a university degree, at 57% versus 86%; maternal education was included among the adjustment factors.
The researchers proposed several possible explanations, including differences involving melatonin, sensitivity to light or noise, rigid routines, anxiety and emotional regulation. However, the study did not test those explanations, so they remain possibilities rather than conclusions.
Why the findings matter
The results suggest that sleep differences in preschool autistic children may involve both timing and sleep continuity. The clearest signals were more frequent night waking and wider variation in weekday bedtimes, while the average difference in total sleep was relatively small.
A separate 2025 study of 666 autistic children aged 2 to 7 in Chongqing also reported small amounts of social jetlag, with median values of 15 to 30 minutes by age group. In that study, greater social jetlag was associated with more severe core autism symptoms, according to the source text. An association does not establish that one factor caused the other.
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