As we elaborate and extend these molecular genetic approaches, it seems likely that the number of genes with variants that contribute to individual differences in human vulnerabilities to addiction and related phenotypes will continue to grow, and that many of the genes listed here will receive additional support. By the time that this review is printed, more detailed data from arrays that contain markers for almost 1 million SNP and 1 million copy number variant probes will enhance the picture that we present here (Liu et al, in preparation). These studies will add power to detect differences in many of the genes and intragenic regions that are not well studied using the 500 – 600k datasets analyzed in this review, and to allow us to understand potential roles of copy number variation in these addiction and related phenotypes. More and more such studies will provide more and more ability to both better understand, better prevent and better treat these common and debilitating conditions.
