Study of the Association between Oxytocin Receptor Gene Polymorphism, Childhood Adversity, and Negative Symptoms of Schizophrenia

It is known that the neurohormone oxytocin plays an important role in the pathogenesis of mental illness and also models the relationship between stress factors, especially those acting in the early stages of development, and the development of mental disorders. On the basis of these data, we investigated the effects of the interaction of the environmental factor, in the capacity of which the childhood adversity (CA) and the oxytocin receptor (OXTR) genotypes in the polymorphic sites rs4686302 and rs7632287 were considered, on the severity of negative symptoms of schizophrenia. The study involved 592 patients with schizophrenia (code F20, according to ICD-10). Information about the presence of CA was obtained from case histories and patient interviews. Analysis of covariance (GML) was used for statistical data processing; in post hoc pairwise comparison, Tukey's test was used. A significant effect of the interaction between CA and OXTR gene polymorphism rs7632287 (G/A) on the severity of negative symptoms in patients with schizophrenia was revealed. In patients without CA, polymorphisms did not have a significant effect on the studied phenotype. Thus, our study showed for the first time that the rs7632287 (G/A) polymorphism and CA have a mutual effect on the severity of negative symptoms of schizophrenia.