Serotonin Receptor 2A Gene Polymorphism (–1438A/G) and Short-Term Treatment Response to Citalopram

The 5-HTR2A gene is a candidate gene for influencing the clinical response to antidepressant treatment. The purpose of this study was to determine the relationship between the –1438A/G polymorphism in the 5-HTR2A gene and the response to citalopram in a Korean population with major depressive disorder (MDD). Citalopram was administered for 4 weeks to the 71 patients who completed this study. We found significant differences in genotype, allele, and carrier distribution between the normal group and MDD patients (genotypes: χ 2 = 6.473, d.f. = 2, p = 0.039; alleles: χ 2 = 5.589, d.f. = 1, p = 0.018; OR = 0.618, 95% CI = 0.414–0.922; allele carriers: χ 2 = 5.383, d.f. = 1, p = 0.020; OR = 0.473, 95% CI = 0.249–0.879). The frequency of the –1438G allele was much higher in MDD patients than in the normal group (allele carriers: χ 2 = 5.383, d.f. = 1, p = 0.020; OR = 0.473, 95% CI = 0.249–0.879). There were also significant differences in response to citalopram according to the –1438A/G variation of 5-HTR2A in MDD patients. The group of remitters carried a higher frequency of the GG allele than of the AA and AG alleles. More of nonremitters carried the A allele than were without it (genotype: χ 2 = 8.016, p = 0.018; allele carrier: χ 2 = 4.512, p = 0.034; OR = 0.324, 95% CI = 0.112–0.936). The response to citalopram differed with the –1438A/G polymorphism genotype and allele carriers. The –1438G/–1438G genotype appeared to be associated with a better response to citalopram, with especially the G allele being related to core depressive symptoms and psychic anxiety improvement (p