Effects of catechol-O-methyltransferase Val158Met polymorphism on the cognitive stability and aggression in the first-onset schizophrenic patients

We assessed catechol-O-methyltransferase (COMT) polymorphism in 132 first-onset schizophrenic patients and 80 healthy controls. The relationship between COMT polymorphism and cognitive function, aggression and psychiatric symptoms was tested in the schizophrenic group. COMT^L carrier had higher digit span score and lower similarity score than COMT^H homozygote. COMT^L carrier had higher attention and delusion scores and lower inappropriate affect scores than COMT^H homozygote. Attention and delusion scores of COMT^L allele were higher than COMT^H allele. COMT^L group had higher aggression than COMT^H homozygote. Our results support the theory that COMT ^L allele was related with increased tonic dopamine activity and cognitive 'stability', which may induce cognitive inflexibility in schizophrenia.