shared environmental influences and its substantial (but slighter lower) heritability estimate of 40%. It was also more similar than the EA model to findings reported in the few prior twin studies examining problem use, which produced heritability estimates of 41% for “getting into a situation you later regretted” (Fowler et al., 2007) and 78% for one or more AUD symptoms (Rhee et al., 2003). Of note, both Fowler et al.’s and Rhee et al.’s studies were conducted with adolescents, for whom there are significant environmental constraints on heavy use and even minor alcohol-related consequences are highly deviant. Environmental constraints on problem alcohol use may exert themselves in African Americans as well.
