Genotypes and relative reduction of Hamilton Depression Rating Scale (HAM-D) score in the patients treated with desipramine and fluoxetine. Histograms represent mean and standard error of mean for relative reduction of HAM-D21 score in major depressive disorder (MDD) patients who completed 8-week antidepressant treatment with desipramine (n = 68) or fluoxetine (n = 79) by genotypes (light blue, homozygous for minor allele; orange, heterozygote; dark blue, homozygous for major allele). A general linear model was used to detect allelic additive effects on treatment response after adjustment for age, sex and baseline HAM-D21 score. The analyses were performed using all treated patients (a), desipramine-treated patients (b) and fluoxetine-treated patients (c).