Review and meta-analysis of antidepressant pharmacogenetic findings in major depressive disorder

This systematic review summarizes pharmacogenetic studies on antidepressant response and side effects. Out of the 17 genes we reviewed, 8 genes were entered into the meta-analysis (SLC6A4, HTR1A, HTR2A, TPH1, gene encoding the beta-3 subunit, brain-derived neurotrophic factor (BDNF), HTR3A and HTR3B). TPH1 218C/C genotype (7 studies, 754 subjects) was significantly associated with a better response (odds ratio, OR = 1.62; P = 0.005) with no heterogeneity between ethnicities. A better response was also observed in subjects with the Met variant within the BDNF 66Val/Met polymorphism (4 studies, 490 subjects; OR = 1.63, P = 0.02). Variable number of tandem repeats polymorphism within intron 2 (STin2) 12/12 genotype showed a trend toward a better response in Asians (STin2: 5 studies, 686 subjects; OR = 3.89, P = 0.03). As for side effects, pooled ORs of serotonin transporter gene promoter polymorphism (5-HTTLPR) I (9 studies, 2642 subjects) and HTR2A - 1438G/G (7 studies, 801 subjects) were associated with a significant risk modulation (OR = 0.64, P = 0.0005) and (OR = 1.91, P = 0.0006), respectively. Interestingly, this significance became more robust when analyzed with side effect induced by selective serotonin reuptake inhibitors only (5-HTTLPR: P = 0.0001, HTR2A: P < 0.0001). No significant result could be observed for the other variants. These results were not corrected for multiple testing in each variant, phenotype and subcategory. This would have required a Bonferroni significance level of P < 0.0023. Although some heterogeneity was present across studies, our finding suggests that 5-HTTLPR, STin2, HTR1A, HTR2A, TPH1 and BDNF may modulate antidepressant response. Molecular Psychiatry (2010) 15, 473-500; doi:10.1038/mp.2008.116; published online 4 November 2008