Hostname: page-component-74656f9884-npj9w Total loading time: 0 Render date: 2026-11-06T23:22:22.802Z Has data issue: false hasContentIssue false

The codevelopment of internalizing symptoms, externalizing symptoms, and cognitive ability across childhood and adolescence

Published online by Cambridge University Press:  07 October 2019

Efstathios Papachristou*
Affiliation:
Department of Psychology and Human Development, UCL Institute of Education, University College London, London, UK
Eirini Flouri
Affiliation:
Department of Psychology and Human Development, UCL Institute of Education, University College London, London, UK
*
Author for Correspondence: Efstathios Papachristou, Department of Psychology and Human Development, UCL Institute of Education, University College London, 25 Woburn Square, London WC1H 0AA, UK; E-mail: efstathios.papachristou@ucl.ac.uk.
Rights & Permissions [Opens in a new window]

Abstract

Cognitive ability, externalizing symptoms, and internalizing symptoms are correlated in children. However, it is not known why they combine in the general child population over time. To address this, we used data on 17,318 children participating in the UK Millennium Cohort Study and followed-up five times between ages 3 and 14 years. We fitted three parallel-process latent growth curve models to identify the parallel unfolding of children's trajectories of internalizing symptoms, externalizing symptoms, and cognitive ability across this period. We also examined the effects of time-invariant (ethnicity, birth weight, maternal education and age at birth, and breastfeeding status) and time-varying covariates (maternal psychological distress and socioeconomic disadvantage) on the growth parameters of the trajectories. The results showed that the intercepts of the trajectories of cognitive ability and, particularly, externalizing symptoms were inversely correlated. Their linear slopes were also inversely correlated, suggesting parallel development. Internalizing symptoms were correlated positively with externalizing symptoms and inversely (and more modestly) with cognitive ability at baseline, but the slope of internalizing symptoms correlated (positively) only with the slope of externalizing symptoms. The covariates predicted 9% to 41% of the variance in the intercepts and slopes of all domains, suggesting they are important common risk factors. Overall, it appears that externalizing symptoms develop in parallel with both cognitive ability and internalizing symptoms from early childhood through to middle adolescence. Children on an increasing trajectory of externalizing symptoms are likely both increasing in internalizing symptoms and decreasing in cognitive skills as well, and are thus an important group to target for intervention.

Figure 0

Table 1. Unweighted estimates of internalizing symptoms, externalizing symptoms, cognitive ability, and covariates across sexes

Figure 1

Table 2. Mean growth parameter estimates (intraindividual development) of parallel-process latent growth curves of internalizing symptoms, externalizing symptoms, and cognitive ability adjusted for time-invariant and time-varying covariates

Figure 2

Table 3. Crude and adjusted residual variance estimates (interindividual differences) of parallel-process latent growth curves of internalizing symptoms, externalizing symptoms, and cognitive ability

Figure 3

Table 4. Unstandardized regression coefficients (SE) of covariates on the growth parameters of the fully adjusted parallel-process latent growth curve model of internalizing symptoms, externalizing symptoms, and cognitive ability

Figure 4

Figure 1. Predicted latent growth curve trajectories of internalizing symptom scores, externalizing symptom scores, and cognitive ability scores in males with time-varying and time-invariant covariates held to their mean (average) and to their extreme (low-risk and high-risk) values.

Figure 5

Figure 2. Predicted latent growth curve trajectories of internalizing symptom scores, externalizing symptom scores, and cognitive ability scores in females with time-varying and time-invariant covariates held to their mean (average) and to their extreme (low-risk and high-risk) values.

Figure 6

Figure 3. Linear and nonlinear trajectories of internalizing symptom scores, externalizing symptom scores, and cognitive ability scores in males.

Figure 7

Figure 4. Linear and nonlinear trajectories of internalizing symptom scores, externalizing symptom scores, and cognitive ability scores in females.