Biomarkers for bipolar disorder

Abstract Biomarkers can be used in medicine for diagnosis, prognosis, or treatment guidance. In bipolar disorder, biomarkers have been studied not only to identify specific features associated with the diagnosis but also to detect illness activity related to mood episodes. Although the clinical use of biological markers is not possible yet, biomarker research in bipolar disorder has helped advance understanding of the pathophysiology and the neurobiological processes underlying this complex illness. With the increasing shift in psychiatry toward personalized medicine, biomarkers may aid in developing improved tools for risk assessment and treatment selection. In this chapter, we review candidate biomarkers studied in bipolar disorder, exploring evidence for the peripheral molecules (including BDNF, inflammatory markers, oxidative stress markers, and hypothalamic-pituitary-adrenal axis markers), “omics,” and neuroimaging markers, both structural and functional.