genetic and environmental influences impact substance use may vary in AA populations, just as the rates of alcohol use vary in AA populations.30 In other words, the etiological pathways that influence risk for complex behavioral outcomes could vary across groups. Ignoring the heterogeneity within and across populations and assuming a “one size fits all” developmental model based largely on research conducted in EAs is unlikely to accurately represent the etiological factors operating in AAs and/or populations other than EAs. With the limited number of AA twins available for study it remains unknown to what extent genetic and environmental factors are important in impacting alcohol use milestones and outcomes in AAs. One could imagine that the disproportionate burden of environmental stressors experienced by AAs in our society could lead to a difference in the relative importance of the environment, as compared to genetic predispositions, in impacting substance use outcomes.
