Objectives: Dysfunctions of the "social brain" belong to the core features of schizophrenia. The neurohormone oxytocin (OXT), mediated through its specific receptor (OXTR), is involved in the regulation of social behaviour and social cognition. Previous research has suggested a role of OXT system genes in disorders of social reciprocity. Preliminary evidence points to an association of peripheral OXT levels as well as OXT and OXTR gene polymorphisms with psychotic symptoms and treatment response in schizophrenia. This study aims to determine a possible contribution of OXT and OXTR genetic variations to schizophrenia susceptibility.
Methods: Using n = 406 individuals diagnosed with schizophrenia according to DSM-IV and n = 406 healthy controls matched for age and gender in a case-control design, two single nucleotide polymorphisms (SNPs) within the OXT gene (rs2740204, rs2740210) and four SNPs within the OXTR gene (rs53576, rs237880, rs237885, rs237902) that were previously investigated in other studies were genotyped.
Results: Chi(2)-testing suggested significant associations of OXTR SNPs rs53576(A > G) (P = 0.008) and rs237885(T > G) (P = 0.025) with a diagnosis of schizophrenia. Post-hoc ANCOVA revealed significant associations of OXTR SNPs rs53576 with general psychopathology and rs237902 with negative symptom scores in schizophrenic patients.
Conclusions: Our findings support hypotheses about an involvement of oxytocinergic gene variants in schizophrenia vulnerability and warrant independent replication.