of externalizing behavior emerged: a stable, high externalizing class and a moderate, decreasing externalizing-behavior class. The GABRA2 gene was associated with class membership, with subjects who showed persistent increased trajectories of externalizing behavior more likely to carry the genotype previously associated with increased risk of adult alcohol dependence. A significant interaction with parental monitoring emerged; the association of GABRA2 with externalizing trajectories diminished with high levels of parental monitoring.43
