The present study brings together the literatures on mechanisms of intergenerational continuity in externalizing disorders (Chassin et al., 1993; Sher et al., 1997; Thornberry et al., 2003) and gene-environment interplay (Dick, 2011; Feder, Nestler, & Charney, 2009), and offers a new perspective on central questions regarding the factors that promote intergenerational continuity versus discontinuity in externalizing psychopathology. Using longitudinal data from the CDP sample, we found evidence for an indirect effect whereby parental externalizing behavior (as indexed by measures of antisocial behavior and alcohol dependence symptoms) predicts a greater number of life events, which in turn predict higher adolescent externalizing behavior for those with a specific GABRA2 genotype. The association between life events and subsequent externalizing behavior was stronger for adolescents who were homozygous for the major allele compared to those who were heterozygous or homozygous for the minor allele. A similar interaction was found in the FinnTwin12 sample, although the effects did not replicate at a statistically significant level of p < .05.
