Third, in contrast to previous studies, we did not find evidence for an indirect effect from parental externalizing→life events→adolescent externalizing at the population level in the community-based CDP sample. Rather, this indirect effect was only observed for adolescents who were homozygous for the major allele at rs279871. Although analyses in Chassin’s sample of children of alcoholics and a demographically matched comparison group (Chassin et al., 1993) and in the population-based FinnTwin12 sample (reported here) find evidence for this indirect effect, others have reported null results (Hoffmann & Su, 1998a). We believe that the mixed findings for this effect underscore the need to test hypotheses regarding the individual difference factors (genetic or otherwise) that alter the strength of this intergenerational pathway.
