Biomarkers and detection methods of bipolar disorder.

Bipolar disorder is one of the severe mental diseases. Its high misdiagnosis rate and long-time delayed diagnosis are related to the fact that the diagnosis procedure is mainly conducted by doctors' subjective judgment. The diagnosis methods of bipolar disorder mainly include the International Classification of Diseases (ICD) or the Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria and clinical guidelines based on clinical performance. To help psychiatrists make a more accurate diagnosis, in vitro diagnostic (IVD) techniques for bipolar disorder have been developed as the biomarkers research on bipolar disorder steadily increases. Here, we systematically review the recent studies in this area, summarizing the development of instant test products, potentially benefiting clinicians and their patients. The controversy over these biomarkers is discussed, pointing out that multilevel testing with more than one biomarker may provide better confidence in diagnoses. In some cases, more attention should be paid to the different reference values of some biomarkers in terms of age, gender, etc. The review on biomarkers for bipolar disorder may open new doors for the development of point-of-care testing (POCT) and instructing the R&D of future products.