We found that these life events × GABRA2 interaction effects accounted for more variance in teacher reports of adolescent externalizing compared to the mother reports. Although this difference in magnitude was not initially hypothesized, our findings suggest that adolescents may act out at school in response to family-related changes and stressors to a greater degree than they act out at home, and that this varies as a function of genotype. It is also possible that teacher reports are more sensitive to variation in externalizing behavior because teachers have more expertise about the range of adolescents’ behavior or because the school situation elicits a wider range of externalizing behavior. We note that the G × E effects observed in CDP did not replicate at a statistically significant level in the FinnTwin12 sample; however, the pattern of the genotypic effects was in the same direction. There was reduced power to find effects in FinnTwin12 because there were a fewer number of total observations relative to CDP owing to the CDP’s longitudinal repeated measures design. As expected given the reduced degrees of freedom,
