Plasma unconjugated bile acids as novel biomarker for schizophrenia

In this study, we measured conjugated and unconjugated free bile acids (BAs) in plasma from patients with schizophrenia and healthy subjects to examine the possibility of BA as a biomarker for schizophrenia. Although the levels of each BA conjugate showed no significant differences, significant differences for three unconjugated bile acids were observed in the plasma between patients with schizophrenia and healthy subjects. Additionally, a more than three times difference between patients and healthy subjects was observed in the mean value of the total concentrations of primary BAs. These results indicate that cholic acid and chenodeoxycholic acid levels in plasma may be novel diagnostic markers for a sub-population of patients with schizophrenia. Thus, future studies should elucidate the relationship between this increase in BA levels and the pathology of schizophrenia and verify the potential of unconjugated BA in plasma as biomarkers for schizophrenia. [Display omitted] •Unconjugated bile acid (BA) levels in plasma of schizophrenic patients were significantly increased.•The levels of conjugated BA showed no significant differences in plasma of schizophrenic patients.•There are positive correlations among unconjugated BA level in plasma of schizophrenic patients.•The primary BA levels in plasma may be novel diagnostic markers for a sub-population of schizophrenia.