Sleep disturbances and emotional dysregulation in young children with autism spectrum, intellectual disability, or global developmental delay

Objective: Sleep disturbance and emotional dysregulation (ED) are common and often functionally impairing in young children with neurodevelopmental disorders (NDD). This study investigated the relationship between sleep disturbance and ED in a sample of preschoolers with ASD, intellectual disability, or global developmental delay, and examined possible predictors of their persistence over time. Methods: All children under 6 years of age clinically referred between July 2018 and May 2022 to two neuropsychiatric specialized centers for NDD received a comprehensive diagnostic evaluation, including the Child Behavior Checklist 1.5-5 (CBCL), the Autism Diagnostic Observation Schedule-2 (ADOS-2), and standardized tests of cognitive and global development. Sleep disturbances were assessed with the CBCL-sleep score, and ED with the CBCL Attention, Aggression, and Anxious/Depressed scales (CBCL-AAA). A reassessment of sleep and ED was conducted after 6 months or longer, including the Child Sleep Habits Questionnaire (CSHQ). Multivariate analyses and mixed linear regression models were conducted. Results: A total of 136 children, 75.7% male, median age 38.27 months, IQR 15.39, 41.2% with global developmental disorder (GDD) or intellectual disability (ID) participated in the study. Of them, 64.7% were diagnosed with autism spectrum disorder (ASD) and 35.3% with other NDD (w/o ASD). Sleep disturbances (CBCL-Sleep) and ED (CBCL-AAA) were positively correlated (p < 0.001), after accounting for age, ID/GDD and autism symptom severity, in both the entire sample and separately in each diagnostic group (ASD and NDD w/o ASD). Seventy-five children (55%) were reassessed a mean 17.2 months afterwards. There was persistence of the positive correlation between sleep problems and ED (p < 0.001) in both the entire sample and each diagnostic group. The longitudinal mixed linear model showed that ED at follow-up was predicted by baseline sleep problems (p = 0.008), ED (p < 0.001), and ASD severity (p = 0.015). Conclusions: Sleep disturbances are significantly associated with ED in young children with NDD, either with or without ASD, both cross-sectionally and prospectively over time. Sleep problems represent an important comorbidity and a potential treatment target for improving emotional stability in NDD.