from a prospective, longitudinal, community sample of 250 Caucasian males who are part of the Child Development Project (Dodge, Bates, & Pettit, 1990). The effects of childhood maltreatment on behavior have been reported previously for this sample. Dodge, Bates, and Pettit (1990) reported adverse effects of pre-kindergarten physical maltreatment on classroom aggressive behavior. Lansford and colleagues (2002) found that aggression levels, reported at age 16, were nearly twice as high in individuals who had been maltreated before kindergarten as in non-maltreated children. Abused children were also more likely to be arrested as late juveniles or early adults (Lansford et al., 2007). Here we test for interaction effects between childhood maltreatment and MAOA uVNTR genotype in relation to a composite measure of externalizing behavior spanning childhood through early adulthood.
