Variation in DRD2 has been investigated for its effect on bupropion treatment response (David et al. 2007). David et al. (2007) found that smokers with the A2/A2 genotype at Taq1A who received bupropion (150 mg/day for the first 3 days, then 300 mg/day) were three times more likely to abstain from smoking at the end of the trial compared to A2/A2 subjects receiving placebo. This difference was not observed for the other genotypic groups.
