Codevelopment of externalizing and internalizing problems in early childhood.

Using cross-domain latent growth modeling, we examined trajectories of externalizing and internalizing problems in disadvantaged boys followed from ages 2 to 6 years (N = 303). On average, externalizing problems gradually decreased and internalizing problems gradually increased. However, we found significant variability in individual-level trajectories. Higher levels of externalizing problems were associated with higher levels of internalizing problems; rates of change were also positively correlated across domains. In addition, high levels of externalizing problems predicted rapid increases in internalizing problems. In follow-up analyses involving child and parenting factors, the combination of high negative emotionality, low fearfulness, and high negative maternal control preceded high, nondecreasing externalizing trajectories. The combination of high negative emotionality, high fearfulness, and high negative maternal control preceded high, increasing internalizing trajectories. Taken together, the results indicate both general and specific processes in the development of early externalizing and internalizing problems.