Follow-up mediational analyses did not support models in which level of response to alcohol mediated the relationship between this SNP (rs1497571) of the GABRG1 gene and drinking behaviors in our sample. It is possible that the effects of this SNP on drinking behavior may be mediated through alternative risk mechanisms, such as conduct disorder, for example, which has also associated with variation in the GABRA2 (Agrawal et al., 2006; Dick et al., 2006b). This study could not directly test the mediating role of conduct disorder, or more broadly, antisocial traits. However, future genetic studies testing such mediational models seem warranted. These models have the potential to advance the field from the identification of genes that are related to psychiatric phenotypes to understanding how specific genes are involved in the development of psychiatric disorders, which represents an important challenge and future direction in the field of psychiatric genetics (Dick et al., 2006d).
