Meta-analysis of BDNF Val66Met polymorphism association with treatment response in patients with major depressive disorder.

The aim of our meta-analysis was to assess the association between BDNF Val66Met polymorphism and treatment response in patients with MDD. 8 studies that included data from 1115 subjects were identified. We tested two phenotypes: response rate and remission rate. OR was used as a measure of the effect of the association in a fixed/random effect model. Meta-analysis was performed for genotypes Met/Met versus Val/Val, Val/Met versus Val/Val, Met/Met versus Val/Met, Val/Met+Met/Met versus Val/Val, Met/Met versus Val/Val+Val/Met, and Met allele versus Val allele. When all groups were pooled, a significant association of Val/Met genotype and increased response rate was found in comparison to Val/Val in overall population (OR=1.66, 95%CI=1.07-2.57, P=0.02). In the subgroup analysis, similar result was shown in Asian population (OR=1.83, 95%CI=1.03-3.26, P=0.04), but not in Caucasian population. We didn't observe a significant association of BDNF Val66Met polymorphism with remission rate. This meta-analysis demonstrates the association between BDNF Val66Met polymorphism and treatment response in patients with MDD, and Val66Met heterozygous patients have a better response rate in comparison to Val/Val homozygote patients, especially in Asian population. Copyright 2009 Elsevier B.V. All rights reserved.