Intellectual Disability and Child Behavior Problems in Early Childhood

Background: School-aged children and adolescents with intellectual disability (ID) are more likely to have psychosocial and behavioral problems; however, it is unknown when these disparities emerge. This study sought to identify behavioral disparities among young children with and without ID using a nationally-representative, population-based contemporary cohort of US infants.

Methods: Data are from 8,490 infants participating in the 9-month wave of the Early Childhood Longitudinal Study, Birth Cohort. ID was defined by the lowest 10% of mental scale scores from the Bayley Short Form-Research Edition. Child behavior was measured using the Infant/Toddler Symptom Checklist (ITSC). Multivariable regression examined child behavior by ID status, with a specific focus on sociodemographic and maternal health characteristics.

Results: 8.6% of infants exhibited ID at 9 months. Infants with ID were more likely to be male, born small-for-gestational age or low birthweight, have a chronic health condition, and live in poverty than infants without ID. Behavior problems did not differ between infants with and without ID. In adjusted analyses, maternal depressive symptoms (Beta=1.9; p-value<.001) and poor maternal health (Beta=0.9; p-value<.001), but not ID were associated with child behavior problems. Adverse gestational outcomes, poverty, socioeconomic status, and family structure were not associated with early child behavior problems.

Conclusions: Disparities in behavior problems among children with ID are not evident in early childhood. Poor maternal health is a risk factor for behavior problems among all children. Behavioral screening for children with ID should begin at an early age when interventions may be most effective.