In summary, these analyses explore the dynamic nature of genetic effects on alcohol consumption from adolescence to adulthood in a population-based sample of male twins. We report evidence of two latent genetic factors: one that is influential during mid-adolescence to early adulthood, but whose effects decline thereafter; and a second whose effects are modest during adolescence and increase gradually into adulthood. Consistent with previous reports, shared environmental influences decrease over time. While early unique environmental factors are largely time-specific in their influence, by early adulthood, these factors’ effects are influential across epochs. These findings have important implications in gene identification efforts for alcohol related phenotypes, and could also inform research on the continuity or discontinuity of behavioral phenotypes across development, as they indicate that different genetic factors can underlie the same phenotype from adolescence into adulthood.
