Patterns of Early Development in Children with ADHD

The primary aim of this study was to compare early trajectories of cognitive/motor development and adaptive functioning between school-aged children with attention-deficit/hyperactivity disorder (ADHD) and typically developing (TD) children. A secondary, more exploratory, aim was to determine whether groups differed in their eligibility for early intervention services at individual timepoints.

This study leveraged data from three prospective longitudinal studies of infants with and without a family history of autism. Our sample was majority male, White, and non-Hispanic. At 6, 12, 18, 24, and 36 months, cognitive/motor development was measured via direct assessment using the Mullen Scales of Early Learning, and adaptive functioning was measured via parent report using two editions of the Vineland Adaptive Behavior Scales (Vineland ABS, Vineland-II). At school age (~6-16 years), children were assigned outcomes of ADHD (n = 62) and TD (n = 123). Linear mixed-effects models were used to estimate subscale-level trajectories, while chi-squared or Fisher's exact tests were used to test for group differences in rates of service eligibility.

Trajectories often varied by group. Children with ADHD had lower estimated raw scores on all subscales of the Mullen Scales of Early Learning and nearly all subscales of the Vineland-II than TD children. Further, the ADHD group had higher rates of service eligibility in several domains, particularly communication and socialization.

These findings suggest that children with ADHD differ in early trajectories of cognitive/motor development and adaptive functioning, and that children at elevated likelihood for ADHD may benefit from increased screening and supports for delays.