The DRD2 rs1799732 [ − 141delC] was genotyped in the same manner using a custom designed TaqMan assay [forward primer: 5′ CAA AAC AAG GGA TGG CGG AAT C; reverse primer 5′ CCA CCA AAG GAG CTG TAC CT; reporter 1 sequence (VIC): 5′ TAC CCG TTC CAG GCC G; reporter 2 sequence (FAM): 5′ CTA CCC GTT CAG GCC G].