Different neurocognitive functions regulating physical aggression and hyperactivity in early childhood

Background: There are strong parallels between early childhood and adolescent behavior problems. However, we do not know if behavioral symptoms associate with neurocognitive processes in very young children as they do in older children. Methods: We studied a population-based birth cohort of children (N= 1,950) whose developmental trajectories of physical aggression and hyperactivity were assessed between the ages of 17 and 41 months. We measured the following neurocognitive abilities at 41 months of age: Receptive vocabulary, visuospatial organization, and short-term memory. Results: After controlling for other neurocognitive abilities, frequent physical aggression was related specifically to receptive vocabulary deficits (p < .0001) while frequent hyperactivity was related specifically to deficits of visuospatial organization (p < .0001). The pattern of associations was robust despite controls for socioeconomic and perinatal status. Conclusions: The different neurocognitive correlates of physical aggression and hyperactivity problems observed during adolescence are apparent in earlv childhood. Whereas physical aggression problems are associated with language deficits, hyperactivity problems are related to non-verbal deficits.