Understanding the biological and environmental etiologies underlying alcohol-use phenotypes is critical for the development of effective prevention programming and treatment strategies. In particular, the use of twin and family studies to delineate dynamic genetic influences on these phenotypes across time can inform gene identification efforts: in the event that a single genetic factor influences an alcohol-related outcome differentially over time, it might be possible to ascertain a sample based on the age range within which those genetic influences are most prominent. Alternatively, if twin studies suggest that qualitatively distinct genetic factors influence the same alcohol phenotype during different time-frames, gene identification studies should be designed that limit the age range of the sample so as to minimize genetic heterogeneity underlying the phenotype of interest. The aim of the current analyses was to use a genetically informative, population-based sample of male twins to determine whether genetic influences on alcohol consumption change, quantitatively (i.e. genetic attenuation) and/or qualitatively (i.e. genetic innovation), from early adolescence into mid-adulthood.
