This review began with a summary of quantitative genetic studies establishing the heritability of the substance misuse diagnoses as well as the increased heritability of a more severe form of alcohol and drug dependence characterized by symptoms of increased tolerance and withdrawal. The review then presented evidence from linkage analyses and candidate gene studies suggesting relations between specific genes and genomic regions and the substance misuse diagnoses. The reviewed linkage analyses suggest that the genes influencing risk for substance dependence and related phenotypes, such as body mass index, drug sensitivity/tolerance, EEG patterns and antisocial personality traits, are many and reside on several chromosomal regions (see table 1). It appears that these regions are not unique to Native Americans, as similar findings have been reported in studies in other ethnic (primarily Caucasian) groups. Some overlap in the gene locations for substance dependence and body mass index have been found suggesting the possibility of a common genetic substrate for disorders of consumption.
