An additive, continuous genetic efficacy (AGES) score was calculated for each locus (range 0–2) based on the number of putative ‘efficacy’ alleles for moderation of bupropion efficacy for smoking cessation (i.e., [COMT: 0 = GG, 1 = GA; 2 = AA]; [DRD2: 0 = AA, 1 = AG, 2 = GG]; [DRD4: 0 = SS; 1 = SL; 2 = LL]; [SLC6A3: 0 = 99; 1 = 9*; 2 = **]) (23). An AGES quotient was calculated for each participant based on the number of efficacy alleles they possessed divided by the total number of possible alleles (range: 0–8). The quotient adjusts for missing genetic data such that the denominator would be 8 if data for all 4 polymorphisms was available but would only be 6 if one of the genotypes were not available. The AGES quotient was calculated only for participants with genotype data available for two or more polymorphisms (see Table 1). The same algorithm for coding AGES was used in both studies.
