Longitudinal data on Dutch mono- and dizygotic twin pairs (N = 8013 pairs) are analyzed to decompose the stability of the CBCL-JBD phenotype into genetic and environmental contributions.
Heritability of the CBCL-JBD increases with age (from 63%to 75%), whereas the effects of shared environment decrease (from 20%to 8%). The stability of the CBCL-JBD phenotype is high, with correlations between .66 and .77 across ages 7, 10, and 12 years. Genetic factors account for the majority of the stability of this phenotype. There were no sex differences in genetic architecture.
Roughly 80%of the stability in childhood CBCL-JBD is a result of additive genetic effects.