Developmental multi-trajectory of irritability, anxiety, and hyperactivity as psychological markers of heterogeneity in childhood aggression.

Background: A growing body of evidence suggests that child aggression is likely to be driven by multiple developmental pathways. However, little is known about the complex interactions between developmental trajectories of child psychological factors (such as anxiety, irritability, and hyperactivity/impulsivity dimensions) and their associations with aggression from childhood to adolescence. Therefore, the current study aimed to identify clusters of individuals with different developmental multi-trajectory, investigate their early risk factors, and describe their longitudinal associations with physical aggression.

Method: The sample comprised 4898 children derived from the Fragile Families and Child Wellbeing Study. A parallel process growth mixture model was used to identify developmental multi-trajectory groups at 5, 9 and 15 years old. Associations between multi-trajectory group membership and physical aggression were examined with Generalized Estimating Equations models. Finally, multinomial logistic regression was performed to assess perinatal and early risk factors for multi-trajectory groups.

Results: Multi-trajectory groups differed in the magnitude of risk for exhibiting physical aggression, compared to typically developing children. The risk for physical aggression was the most prominent in children who were hyperactive/impulsive and irritable [odds ratio (OR) 6.47; 95% confidence interval (CI) 5.44-7.70] and hyperactive/impulsive, irritable, and anxious (OR 7.68; CI 6.62-8.91). Furthermore, maternal cigarette and alcohol use during pregnancy and maternal depression consistently predicted multi-trajectory groups characterized by problematic levels of at least two co-occurrent psychological symptoms.

Conclusions: Identified combinations of developmental trajectories of psychological characteristics were associated with different magnitude in risk for exhibiting physical aggression. These results may highlight the heterogeneity of developmental trajectories associated with childhood aggression.