Single nucleotide polymorphism rs1497571 of the GABRG1 gene was associated with both level of response to alcohol and drinking patterns and alcohol problems. Level of response was, in turn, associated with drinking patterns and alcohol problems. This pattern of results led us to test a follow-up mediational model in which the effects of SNP rs1497571 of GABRG1 on drinking behavior are mediated by level of response to alcohol. Analyses used Baron and Kenny’s (1986) conceptual approach and formal tests of the significance of the indirect effects based on Preacher and Hayes’s (2004) bootstrapping estimation approach. This approach is appropriate for small sample sizes because it avoids distributional assumptions and calculates a reliable estimate of the indirect effect and its significance by taking a large number of samples from the data (Preacher and Hayes, 2004).
