association between GABRA2 and an elevated persistent trajectory of externalizing behavior across adolescence and emerging adulthood (Dick et al., 2009). However, that study used a latent class approach to test for genetic association with a relatively extreme phenotype; in contrast, we used dimensional measures of externalizing. The fact that we did not find main effects for GABRA2 in CDP or FinnTwin12 samples may be attributable to differences in ascertainment and measurement strategies.
