Effortful Control Shares Genetic and Environmental Influences with Adolescent Internalizing and Externalizing Problems

The youth internalizing and externalzing problems are commonly co-occurring, which is due to common genetic and environmental influences. However, the underlying mechanisms linking these common influences on the two problem domains remains unclear. Using a sample of 2,632 twins (680 monozygotic and 636 dizygotic twin pairs; 51.1% girls) aged 9–19 (M = 13.71, SD = 2.41), this study conducted multivariate twin analyses. Findings suggest that effortful control shares both genetic and non-shared environmental influences with youth internalizing and externalizing problems. Effortful control partially accounted for the common genetic and environmental influences on two domains of problems. These findings underscore the important role of effortful control in explaining for genetic and environmental etiologies of co-occurring youth internalizing and externalizing problems.