Association of Interleukin-6 Polymorphisms with Schizophrenia and Depression: A Case-Control Study.

OBJECTIVE: Growing evidence suggests a crossover in genetic susceptibility to schizophrenia and depression. We aimed to investigate the association of the rs1800795 and rs1800796 polymorphisms of the IL-6 gene with schizophrenia and depression in the Han Chinese population, combined with IL-6 serum levels. METHODS: Gene sequencing and enzyme-linked immunosorbent assay were performed on 113 subjects with schizophrenia, 114 subjects with depression, and 110 healthy controls. RESULTS: Our findings showed that IL-6 concentrations in schizophrenia and depression groups were significantly higher than in the control group. The rs1800796 CC genotype and C allele were significantly associated with depression (P = .012 and P < .05, respectively). The rs1800796 CC and CG genotype was significantly associated with chronic schizophrenia (P = .020 and P = .009, respectively). Regarding the rs1800795 polymorphism, only one case of CG genotype was detected. The remainder were of the GG genotype. CONCLUSION: The IL-6 rs1800796 might serve as a protective factor for depression and schizophrenia in the Han Chinese population.