The MAOA and COMT Gene Polymorphisms in Patients with Schizophrenia Committed Homicide

Numerous studies have indicated that aggression and homicide are more frequent among people with schizophrenia than in the general population. There is considerable evidence that schizophrenia involves a dysbalance between subcortical and cortical dopaminergic systems. The major pathways for catecholamine degradation are oxidative deamination through the action of monoamine oxidase A (MAOA) and by methylation through the action of catechol-O-methyltransferase (COMT). Activity of both enzymes is encoded by the corresponding genes-MAOA and COMT. The aim of our study was to analyze the association between the COMT-Val158Met and MAOA-uVNTR polymorphisms and the risk of committing homicide by patients with schizophrenia. Methods: The study included 50 Caucasian male patients with paranoid schizophrenia (PS). All patients were divided into two groups: Group 1 consisted of 26 PS patients who have committed homicide; Group 2 consisted of 24 PS patients who did not have a history of socially violent behavior. The control group comprised 23 apparently healthy Caucasian men of the same age. All patients underwent clinical-psychopathological and clinical-anamnestic examinations. Molecular genetic studies were performed in the Shared Research Facility Center "High Technologies" at SFedU. Results: Our study revealed no direct correlation between the COMT-Val158Met and MAOA-uVNTR polymorphisms and risk of committing homicide by patients with schizophrenia. At the same time, we detected an association between high-activity gene variants, viz., the MAOA-4R allele and the COMT-158Met/158Met genotype, and the schizoid and unstable premorbid accentuation in patients who had committed murder, whereas the schizoid and unstable accentuation correlated with homicide behavior in patients with schizophrenia. Conclusion: The obtained findings suggest that genetic variation affects the homicidal behavior indirectly, through the various types of premorbid accentuation and confirm the validity of the well-known concept of "syndrome-person-situation," traced back to the mid-20th century, which explains the commission of serious offenses by patients with schizophrenia.