Physical and neurophysiological maturation associated with ADHD among previously institutionalized children: a randomized controlled trial

Background: Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental outcome among children with a history of early institutional care. Prior research on institutionalized children suggested that accelerated physical growth in childhood is a risk factor for ADHD outcomes.

Methods: The current study examined physical and neurophysiological growth trajectories among institutionalized children randomized to foster care treatment (n = 59) or care as usual (n = 54), and never institutionalized children (n = 64) enrolled in the Bucharest Early Intervention Project (NCT00747396, clinicaltrials.gov). Participants completed physical and electroencephalography (EEG) assessments at six time points from infancy through adolescence, as well as structured diagnostic interviews at the 54-month and 12-year time points. A series of multilevel growth models and cross-lagged path models were estimated to examine associations among physical and neurophysiological maturation, treatment group, age of foster care placement, and ADHD diagnostic outcomes.

Results: Twenty-seven percent of the institutionalized children met research criteria for ADHD at one or both time points. Slowed, prolonged growth of height and head circumference were associated with both ADHD and delayed foster care placement. Placement in foster care versus care as usual, but not ADHD, was associated with maturation of the peak alpha frequency. Among children randomized to foster care, average theta-beta ratio was lower among those with ADHD. There was no evidence that rapid physical maturation led to atypical cortical activity.

Conclusions: Delayed, prolonged physical growth and atypical neurophysiology from infancy through adolescence is associated with ADHD among institutionalized children, over and above the protective effects of foster care.