Within‐ and between‐person associations among internalizing and externalizing problems during middle childhood

Abstract Internalizing and externalizing problems are likely to co‐occur in childhood and are related to concurrent and prospective mental health outcomes. We examined the longitudinal relations among internalizing and externalizing problems during middle childhood utilizing the Random Intercept – Cross Lagged Panel Model. We investigated three research questions: (1) how overall levels of internalizing and externalizing problems are related, (2) whether internalizing and externalizing problems predict each other longitudinally, and (3) whether girls and boys show different longitudinal associations among internalizing and externalizing problems. Mother‐reported internalizing and externalizing problems were used through first to sixth grade (N = 1364). Results showed positive random intercepts and positive within‐time correlations of internalizing and externalizing problems. Further, internalizing problems predicted externalizing problems at the within‐person level. Although previous research mostly has shown a significant effect from externalizing problems to internalizing problems, the current study shows that when within‐ and between‐person variance are disentangled, internalizing problems also may predict externalizing problems.