Genotyping of 5-HTTLPR and functional single nucleotide polymorphism (SNP)(A-G) rs 25531 at the promoter region will be performed using polymerase chain reaction (PCR) followed by double restriction endonuclease digestion as reported previously (Wendland et al., 2006) . High resolution agarose gel will be used to determine four alleles: Sa-469 bp (uncut), Sg-402+67 bp, La- 512 bp (uncut), and Lg-402+110bp.