Tumor necrosis factor-alpha -1031T/C polymorphism is associated with cognitive deficits in chronic schizophrenia patients versus healthy controls.

Recent compelling research has demonstrated a pathophysiologic role for proinflammatory cytokines of microglial origin in decreasing neurocognitive function. Psychiatric diseases are already known to have reduced cognitive function and are also associated with increased inflammation. To elaborate on these data, our study aims to investigate how a particular polymorphism of the tumor necrosis factor gene, TNF-α -1031T/C, affects neurocognitive performance in patients with schizophrenia. We recruited 905 patients with schizophrenia and 571 healthy control subjects. We employed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to test for neurocognitive function and the positive and negative syndrome scale to evaluate schizophrenia severity. The -1031T/C polymorphism was genotyped in both healthy controls and schizophrenic patients. Our results demonstrate that patients with the C allele (either T/C or C/C) possessed increased immediate memory index, visuospatial/constructional index, and RBANS total scores as compared to patients without it (p < .05). In healthy controls, there was no significant difference across genotypes (p > .05). Our findings demonstrate that the TNF-α -1031T/C polymorphism may not play a role in the susceptibility of schizophrenia itself, but may be involved in the cognitive deficits of schizophrenia. This suggests an important role for cytokine signaling in mediating the severity of cognitive dysfunction in schizophrenia.