Current state of biomarkers in bipolar disorder.

Bipolar disorder (BD) is a chronic psychiatric illness of which the etiology remains unknown. Extensive research has provided some hypotheses for the pathophysiology of this disorder; however, there are no molecular tests available to help support the diagnosis obtained by self-report and behavioral observations. A major requirement is to identify potential biomarkers that could be used for early diagnosis in patients susceptible to the disease and for its treatment. The most recently published findings regarding alterations in BD were found to be related to oxidative stress, inflammatory and trophic factor deregulation, and also polymorphisms of genes that are associated with the development of BD. Many of these targets are potential biomarkers which could help to identify the BD subgroups and to advance treatment strategies, which would beneficiate the quality of life of these patients. Therefore, the main objective of this review is to examine the recent findings and critically evaluate their potential as biomarkers for BD.