Among the studied polymoorphisms, the G/G genotype and G allele of c.804‐7C>A—TPH1, the T/T homozygote of c.803+221C>A—TPH1, the A/A genotype and A allele of c.1668T>A—TPH1, the G/G homozygote and G allele of c.‐844G>T—TPH2, and the C/A heterozygote and A allele of c.‐1449C>A—TPH2 were associated with the occurrence of depression. This evidence concerns the gene TPH2 and major depressive disorder.