In order to test the theory that dependence on drugs of abuse may have similar genetic underpinnings to other consumptive disorders such as obesity, the results of the genome scan for “any drug dependence” was compared to a genome scan for body mass index (BMI). Evidence for linkage was found on chromosome 6q25.2-q25.3 for both the ‘any drug’ (LOD score = 3.3) and BMI (LOD score = 2.3) phenotypes. Bivariate analyses of the two phenotypes revealed a combined LOD score of 4.1 at that location with evidence of pleiotrophy (i.e., a single genetic locus influencing more than one trait). This result provides preliminary data suggesting that ‘consumption phenotypes’ may share common genetic determinants thus providing a potential explanation for the elevated rates of substance dependence and obesity in some Native American populations [17].
