The dynamics of internalizing and externalizing comorbidity across the early school years

Abstract

High rates of comorbidity are observed between internalizing and externalizing problems, yet the developmental dynamics of comorbid symptom presentations are not yet well understood. This study explored the developmental course of latent profiles of internalizing and externalizing symptoms across kindergarten, first grade, and second grade. The sample consisted of 336 children from an urban, low-income community, selected based on relatively high (61%) or low (39%) aggressive/oppositional behavior problems at school entry (64% male; 70% African American, 20% Hispanic). Teachers reported on children's symptoms in each year. An exploratory latent profile analysis of children's scores on aggression/oppositionality, hyperactivity/inattention, anxiety, and social withdrawal symptom factors revealed four latent symptom profiles: comorbid (48% of the sample in each year), internalizing (19%-23%), externalizing (21%-22%), and well-adjusted (7%-11%). The developmental course of these symptom profiles was examined using a latent transition analysis, which revealed remarkably high continuity in the comorbid symptom profile (89% from one year to the next) and moderately high continuity in both the internalizing and externalizing profiles (80% and 71%, respectively). Internalizing children had a 20% probability of remitting to the well-adjusted profile by the following year, whereas externalizing children had a 25% probability of transitioning to the comorbid profile. These results are consistent with the hypothesis that a common vulnerability factor contributes to developmentally stable internalizing-externalizing comorbidity, while also suggesting that some children with externalizing symptoms are at risk for subsequently accumulating internalizing symptoms.

Figure 1

LTA model relative information criteria for 2- through 6-profile solutions Notes. BIC = Bayesian Information Criterion; aBIC = sample-size adjusted Bayesian Information Criterion; AIC = Akaike’s Information Criterion.

Figure 2

Factor score means within profiles for the LTA 4-profile solution. Notes. AGG = aggression/oppositionality; HYP = hyperactivity/inattention; ANX = anxiety; WITH = withdrawal.

Figure 3

Schematic diagram of transition pathways between latent profiles. Notes. The size of each circle approximates the prevalence of the profile, and the position of each circle approximates the severity of internalizing and externalizing symptoms within the profile. Transitions between profiles having probabilities greater than 10% are represented with thick arrows and transitions having probabilities between 5% and 10% are represented with thin arrows. AGG = aggression/oppositionality, HYP = hyperactivity/inattention, ANX = anxiety, WITH = withdrawal.