In conducting the present study, we expected that possession of the ALDH2*2 allele would be associated with lower levels of alcohol use, and that this association would become stronger over the course of adolescence and into early adulthood. We predicted, further, that the environmental effects of parent and elder sibling alcohol use, and level of deviant peer behavior, would each moderate the effect of ALDH2 genotype, and that these interactive effects would also increase with the age of the target participants. By studying adopted individuals, we were able to assess the environmental effect of parent and sibling drinking upon ALDH2 effect, unconfounded by shared genetic influences.
