A three SNP haplotype consisting of rs9479757, rs2075572, and rs10485057 was significantly associated with smoking initiation in a European-American cohort, while rs2075572 alone was also associated with nicotine dependence [71]. In the same study, A118G was not associated with nicotine dependence, a finding which was replicated in an independent case-control analysis [71, 72]. Although A118G was not found to be associated with nicotine dependence, other research has linked the variant to a variety of physical responses to nicotine. After smoking, A/A individuals have increased cerebral blood flow to areas of the brain associated with craving [73]. A/A patients also report increased reward from nicotine under negative mood induction and women with the A/A genotype find smoking to be for reinforcing than those with the A/G or G/G genotypes [74, 75]. In contrast to these findings, carriers of the G allele were found to experience more dopamine release in the striatum following smoking [76].
