Investigation of the relationship between the level of vasopressi̇n and oxytoci̇n on soci̇al cogni̇ti̇on i̇n schi̇zophreni̇a

Background: The social cognitive capacity in schizophrenia patients are known to be inadequate. There are many studies investigating the effects of oxytocin and vasopressin on social cognitive capacity. However, the results obtained from the studies are conflicting. In addition, studies have focused on the relationship between social cognition and disease, but not the family effect on social cognitive capacity. Also, there is no focus on the changes of the healthy siblings' social cognitive capacity who have same genetics and grow in the same environment with schizophrenia patients. Aim: In this study, our aim was to determine the level of social cognition in schizophrenia patients, and to compare them with their healthy siblings and healthy controls and also to investigate how blood oxytocin and vasopressin levels effect the social cognitive capacity. Materials and Methods: 35 schizophrenic patients and their siblings age, gender matched control group of 35 healthy people were included in the study. Sociodemographic data form, The Eyes test, WAIS-R vocabulary subtest, WCST have been applied to all subjects; in addition PANSS, BIS scale have been applied to the patients participating in the study. Before applying tests 10 mL of venous blood were taken from all participants and analyzed by ELISA. In the data obtained from biochemical analysis, above and below ± 2 SD values were excluded. Statistical analyzes were performed with the remaining data. Results: In patients and their healthy siblings social cognitive performance and neurocognitive capacity that affects social cognition were observed to be worse than healthy controls. But the difference between healthy siblings and healthy controls did not reach statistical significance. In healthy controls the social cognitive performance was found to be correlated with the blood levels of oxytocin. The finding about the worst social cognitive capacity in schizophrenia patients was consistent with the literature. The social cognitive capacity of the siblings was lower than the healthy controls and we empathized that the genetic and enviromental factors affect the social cognitive capacity and the neurodevelopmental process of the siblings were affected by these factors. There was no difference between the blood vasopressin levels of the participants and we did not find any correlation between social cognition and blood vasopressin levels and these findings were not consistent with the literature that declares the vasopressin effect on social cognition. The additional studies that investigate vasopressin effect on social cognition in schizophrenia patients are required. Conclusion: The social cognitive capacity of the schizophrenia patients was found worse than their helathy siblings and the healthy control. The correlation between the social cognitive capacity and blood oxytocin level was observed. The important role of the oxytocin in the development of the social cognitive capacity was considered and the oxytocin will be useful for modeling and understanding the behaviour. The blood vasopressin levels were not correlated with social cognitive capacity and this finding suggest that the role of vasopressin was suspicious. The knowledge of the factors affecting the social cognitive capacity gives direction to initiatives that aimed at increasing the social cognitive capacity and will benefit in many functional areas such as treatment compliance, social life adaptation of the patients.