A neurodevelopmental disorder, autism, include issues with linguistic, cognitive, and behavioral functioning. No many research with sizable sample sizes on sleep issues in China. Therefore, we conducted a one-week survey and sampled strictly in accordance with the ratio of 1:4, to investigate sleep problems and their correlations in a relatively large sample of children with ASD. Our findings demonstrated that sleep issues were prevalent in autistic kids, particularly in the severe group. The mean score of CSHQ in our study was 51.57 ± 7.16, higher than those reported in China [47.69 ± 9.2827]20, America [47.39 ± 8.212720、48.83 ± 9.682821]. Findings suggest that the severity and rate of sleep disturbances in Chinese children with ASD are comparable to, if not higher than, their counterparts in other countries20.
In a sample of 3–17 years old, sleep difficulties were highest at ages 6–9 for children with ASD21. Our results were the same: a mean age of 5.44 ± 2.87. Both cross-sectional22 and longitudinal23 evidence suggest that sleep disturbances in children with ASD can persist throughout childhood into later life. Early treatment for sleep disturbances for young children with ASD may be warranted8. We should identify sleep problems earlier and improve positively.
On the whole, the male-to-female ratio was 3.22 to 1. The ratio of mild to moderate group was 3.52:1 and 2.91:1 in severe ASD group. The male bias in ASD prevalence is most frequently reported as 4 males diagnosed to every 1 female24,25. Recently, a ‘female protective model’ has been proposed based on genetic studies. Further research needs to be done.
Some results suggest that children with ASD have more prevalent and severe sleep disturbances, consistent with previous studies23,26−30. As mentioned, the types of sleep problems differ. Common symptoms in childhood include difficulty in getting up and maintaining sleep, reduced total sleep time (TST), frequent night awakenings, resistance to bedtime, excessive daytime sleepiness, and behavioral insomnia 31. Studies largely confirm ASD children have increased sleep latency, frequent night waking, and shorter sleep duration 32–34. Their study and ours were comparable in that practically all ASD children had sleep issues, with sleep sweating and bedwetting being the most prevalent parasomnias in the mild to moderate group and sleep sweating and trouble falling asleep in the severe group, respectively. In addition, children with severe ASD were more likely than those with mild to moderate ASD to report sleep onset delay, night waking, parasomnias, sleep disordered breathing, and daytime sleepiness. It showed that high functioning ASD children are more likely to report severe parasomnias: the severe group had higher ratings than the mild to moderate group for issues such long night waking and insufficient sleep on weekdays and weekends. It serves as a reminder that we should focus more on these issues when discussing the sleeping habits of Chinese children with ASD and that future research should study the sleep habits of people with ASD in greater detail. Some results showed that those with low-functioning ASD tended to have longer sleep latency, increased duration of night waking, higher scores on the subscales for night waking and parasomnia, and a higher CSHQ total score than those with high-functioning ASD35. Our findings suggest the opposite: high-functioning ASD children tended to be difficulty in falling asleep, have more serious problems in interrupted sleep, molars at night, and sleep sweating, score higher in CSHQ. Although the mechanism is unclear at present, it need more studies to figure out in the future.
In the clinical setting, family structure is an important consideration. Nuclear family was a risk factor for sleep issues, according to Tables 3 and 4. Perhaps the nuclear family has fewer members and less time to spend with their kids and encourage the development of healthy sleep habits, which ultimately causes greater sleep disturbance.
Mothers' role as caregivers had a negative impact on sleep issues, as seen in Tables 3 and 4. Fathers, as caretakers, were, however, both positive and negative predictors of sleep disturbances. The traditional Chinese culture is mostly responsible for the phenomena. For instance, traditional Chinese moms frequently indulge their kids while also providing for their needs. Fathers are stern role models who instill in their kids the value of following the rules. It is imperative to encourage men to play an active role in their children's sleep education because doing so may be more rational than having mothers look after the kids by themselves.
As indicated in Tables 3 and 4, children are more likely to suffer sleep disturbances the more educated the caregivers are. Parents who have completed elementary school were more likely to experience less sleep issues. The more thorough long-term observation and documentation of sleep issues in ASD children, the greater the degree of caregivers may be associated. Compared to normal mood from our study, emotions that were either too cheerful or too sad during pregnancy are detrimental to sleep difficulties in autistic children. It emphasizes how crucial it is to keep mothers’ mood level during pregnancy.
The nurturing environment significantly influenced sleep issues. The severity of sleep issues increases with the quality of the nurturing environment. This study warns us to provide a supportive environment for ASD kids who have sleep issues. The nurturing environment has a crucial impact in the severity of both autism and particular sleep disorders, meriting clinical attention.
The severity of autism was also influenced by wake-up time, which had a positive linear correlation with CSHQ. It is a crucial sign of a poor prognosis for autism that exhibits a positive linear relationship with the severity of ASD and deserves professional attention. Therefore, enhancing the regulation of night wake time can lessen autistic symptoms. According to the report, night waking is typical of children with autism36, often associated with poor sleep hygiene or maladaptive sleep associations34. A delayed melatonin rhythm has been hypothesized to be associated with prolonged sleep latency, and low melatonin amplitude has been associated with night waking in children with ASD37. These studies have not been reported in previous, so strengthening the management of night and wake symptoms (such as whether taking melatonin improves the prognosis) is worth exploring.
In mild to moderate group, this study found mothers’ educational level and monthly income were also key factors. The more educated the mother, the less likely the child is to have trouble in sleeping. The higher the family's monthly income, the better the child's sleep performance. Notably, the more educated the mother is, the worse her child's sleep problems are. Similarly, we speculate that the higher the mother's education level, the more careful and systematic her observation and recording, and the higher the probability of finding sleep problems. Although children with mild to moderate ASD, highly educated mothers observed and recorded more carefully, and found that the proportion of sleep problems was higher than that of low educated mothers. However, the enthusiasm of timely and early treatment of sleep problems is also high, and the difficulty of treatment of sleep problems in mild to moderate children is relatively easy. It may be the result of early detection and intervention of sleep problems, and eventually become a protective factor. However, in children with severe ASD, early detection cannot change the outcome because it is very difficult to intervene sleep problems.
The relationship between autism severity and sleep disorders is worth thinking about. In a study, there was a positive relationship between the severity of ASD symptoms and problem behavior in patients with no or mild sleep disturbance, while there was no significant relationship between the severity of ASD symptoms and problem behavior in patients with moderate-to-severe sleep disturbance 38. Some studies have reported a significant positive association between autism severity and parent reported sleep problems 39–44. Studies have shown that increased ASD severity raises the likelihood of sleep problems and can worsen the severity of sleep problems45. These findings suggest that sleep problems are part of the autism symptom complex and increase with increasing autism severity46. Besides, the sleep problems may impact on autistic symptoms and emotional and behavior problems41 in children with autism, and also precipitate or aggravate sleep problems and psychological and physical distress of their parents47. Another study has suggested that increased autism severity predicts an increased likelihood of sleep problems40. Sleep disturbances may affect brain development, and even lead to abnormal behaviors that adversely influence normal life and learning. Results showed that ASD children with sleep disturbances had serious autistic behaviors, especially in the domains of daily living skills, social cognition, social communication and intelligence quotient. Sleep disturbances could aggravate autistic behaviors, such as social skill deficits, communication impairments48 and stereotypic behaviors49. May50 found that reduced sleep disturbances were associated with improved ASD symptoms like social ability. More evidence is needed to explore the causality.
Richdale and Schreck proposed that sleep problems in ASD might occur as a result of complex interactions between biological, psychological, social/environmental and family factors, including child rearing practices that are not conducive to good sleep. Any one or combination of these factors might contribute to sleep problems in children with ASD36. The causes of sleep disturbance in children and adolescents with ASD have not been clearly identified. Sleep disturbance is correlated with biological, psychological, and social/environmental factors. Abnormalities in melatonin synthesis, hypersensitivity to environmental stimuli, behavioral insomnia in childhood, delayed sleep phase syndrome, rapid eye movement sleep behavior disorder, and accompanying neurological and psychiatric disorders such as anxiety, depression, and epilepsy are considered as the main causes51. Additionally, neurophysiological and neurochemical abnormalities, abnormal timing of melatonin secretion, comorbid medical conditions and current medications, core ASD symptoms, child-rearing practices, and family stress have been suggested as causes of sleep disturbance52.