Chronotype characteristics in children diagnosed with autism spectrum disorder and the relationship between chronotype characteristics and clinical findings

In our study, we aimed to investigate the chronotype characteristics of children diagnosed with Autism Spectrum Disorder (ASD) and the relationship between these characteristics and the severity of autism symptoms. Additionally, we aimed to examine the relationship between sleep, which is closely related to the concept of chronotype, and the severity of autism symptoms. The study included 100 children aged 4-11 years who were diagnosed with ASD and followed up or newly diagnosed with ASD between July 2022 and July 2023 at the Child and Adolescent Psychiatry Department of Akdeniz University Faculty of Medicine Hospital. Exclusion criteria for participating ASD-diagnosed children were having another metabolic, neurogenetic, or neurological disorder. The ASD diagnoses of the children were made according to the DSM-5 diagnostic criteria, and the degree of autism was determined using the Childhood Autism Rating Scale (CARS). The study utilized several tools, including a sociodemographic data form to obtain sociodemographic information of children with ASD, the Autism Behavior Checklist (ABC) and the Childhood Autism Rating Scale (CARS) to assess the severity of autism symptoms, the Children's Sleep Habits Questionnaire (CSHQ) to evaluate sleep quality, and the Childhood Chronotype Questionnaire (CCQ) to assess chronotype characteristics. When examining the identified chronotype characteristics in children diagnosed with ASD, it was found that 21% of the children were morning types, 59% were intermediate types, and 20% were evening types. Children diagnosed with ASD who had evening chronotype characteristics showed more sleep problems compared to those with intermediate and morning chronotype characteristics (p<0.001). It was also observed that ASD-diagnosed children with sleep problems had higher severity of autism symptoms (p<0.01). ASD-diagnosed children with evening chronotype characteristics had higher severity of autism symptoms compared to those with intermediate chronotype characteristics (p<0.05). In terms of the areas assessed for the severity of autism symptoms, such as interaction with others (p=0.01), emotional responses (p<0.05), visual responses (p<0.05), fear or irritability (p=0.01), nonverbal communication (p<0.05), and activity level (p<0.05), it was found that children with evening chronotype characteristics experienced more severe difficulties compared to children with intermediate chronotype characteristics. It was also observed that ASD-diagnosed children who experienced difficulties in various areas, such as imitation (p<0.05), emotional responses (p<0.05), body use (p<0.05), object use (p<0.01), adaptation to change (p<0.05), visual responses (p<0.01), listening responses (p<0.01), taste, smell, touch responses and use (p<0.01), fear or irritability (p<0.01), nonverbal communication (p<0.05), activity level (p<0.01), and level and consistency of mental responses (p<0.01), had more sleep problems. In conclusion, although studies investigating the relationship between chronotype characteristics and the severity of autism symptoms are limited in both quantitative and qualitative aspects, we believe that this study will contribute to the literature in this field. Our study highlights the relationship between chronotype characteristics and the concept of sleep, which is closely related to chronotype, with the severity of autism symptoms. In this regard, ensuring optimal sleep quality and targeting the optimal functioning of the circadian rhythm may be important in alleviating the severity of autism symptoms, as suggested by our study. Therefore, it is important to routinely inquire about sleep characteristics in children diagnosed with autism during examinations. In order to develop comprehensive intervention programs for children with autism and their families, sleep and circadian rhythm disorders should be thoroughly evaluated and incorporated into behavioral and pharmacological management strategies. Keywords: autism, child, sleep, chronotype, circadian.