or older), or a sample consisting entirely of late adolescents. In other words, including both mature adults and late adolescents/young adults in a sample could complicate gene-finding efforts due to the fact that different genetic factors are influential in different subgroups of the sample, a concern previously articulated by Hansell et al. (2009). One potential implication of this possibility is that the use of a phenotype based on a period of highest use – rather than age-specific use – should be carefully considered, as relevant genetic variants could differ depending on whether that period corresponds to adolescence versus adulthood. Furthermore, while the current study is limited to men, researchers should also be cognizant of the possibility that genetic differences in alcohol consumption exist across genders, and make an effort to account for such differences in gene identification studies.
