“…On the other hand, the COMT gene, located on chromosome 22q11.2 [Grossman, Emanuel, & Budarf, ], encodes COMT, which contributes to the inactivation of catecholamines including adrenaline, noradrenaline, and dopamine. The COMT gene val158met polymorphism was found to be related to many physical as well as psychological diseases such as schizophrenia, depressive disorder, bipolar disorder, attention deficit, and hyperactivity and obsessive compulsive disorders [Barnett, Jones, Robbins, & Muller, ; Cao et al, ; Diaz‐Asper et al, ; He et al, ; Jones et al, ; Konishi et al, ; Lachman, Nolan, Mohr, Saito, & Volavka, ; Liu et al, ; Massat et al, ; Melo‐Felippe et al, ; Qian et al, ; Sampaio et al, ; Seok et al, ; Shimada et al, ; Tukel et al, ; Villemonteix et al, ; Wagner et al, ; Watanabe et al, ; Zhang et al, ]. Val158met polymorphism exerts a significant effect on COMT enzyme activity; the Val allele is associated with high enzymatic activity resulting in lower prefrontal dopamine levels in vivo [Lachman et al, ].…”