The results of this study support the idea that DRD2 is implicated in inhibition and impulsivity. First, individual SNPs rs4648317 and rs12364283, as well as the haplotype block consisting of those SNPs, were associated with better performance on the response inhibition task in a drug-free condition and lower scores on self-reported measurement of impulsivity. Second, analyses of responses to d-amphetamine according to DRD2 showed a significant interaction between the drug and rs12364283 on a response inhibition task, although the groups did not differ in subjective ratings of mood.
