Structural equation modeling (SEM) was applied to CBCL data from 5418, 3562, and 1971 Dutch twin pairs at ages 7, 10, and 12 years.
The CBCL-JBD phenotype occurs in 1%of children at each age. Among the children who meet criteria for the CBCL-AP phenotype ( 5%), between 13 and 20%also meet criteria for CBCL-JBD. The best SEM for CBCL-JBD includes additive genetic, shared and unique environmental factors. The best SEM for CBCL-AP includes dominant and additive genetic and unique environmental factors.
These data suggest that CBCL-JBD is common, and even more common among children who have severe attention problems. CBCL-JBD shows familial aggregation due to both genetic and shared environmental factors.