Background
Haplotype analysis is hypothesized as having better power than individual SNPs in detecting the association between genotype and phenotype, but this approach has rarely been used in studies of the genetics of violent behavior in schizophrenia. The aim of this study was to further examine the role of the COMT gene in violent behavior.
Material and Method
Both individual SNP and haplotype were used to explore associations between COMT polymorphisms and violent behavior in 252 patients with violent behavior and 332 patients without violent behavior of Chinese Han schizophrenics. Then the association between a three-marker haplotype (SNPs rs4680, rs737865, and rs165599) and violent behavior was explored by performing haplotype analysis using SHEsis and PHASE. Finally, the Modified Overt Aggression Scale (MOAS) was used to assess the aggressive or violent behaviors of the patients.
Results
No association was found between the individual SNPs and violent behavior in schizophrenia. However, an association was found between haplotypes and violent behavior. The frequency of the haplotype A-A-G was higher in the case group and that of haplotype G-G-A was higher in the control group. Furthermore, the patients with haplotype A-A-G scored higher on the "physical aggression against objects" subscale of the MOAS than those with the haplotype G-G-A in the case group.
Conclusions
There is an association between COMT gene and violent behavior in Chinese schizophrenics. The haplotypes A-A-G and G-G-A may be used to predict violent behavior in Chinese schizophrenics.

Keywords: Schizophrenia - physiopathology, Psychiatric Status Rating Scales, Polymorphism, Single Nucleotide, Haplotypes, Genotype, Genetic Predisposition to Disease, Catechol O-Methyltransferase - genetics, Asian Continental Ancestry Group - genetics, Adolescent, Violence, young adult