Can Brain-Derived Neurotrophic Factor Be Considered a Biomarker for Bipolar Disorder? An Analysis of the Current Evidence

Abstract

Brain-derived neurotrophic factor (BDNF) plays a key role in brain development, contributing to neuronal survival and neuroplasticity. Previous works have found that BDNF is involved in several neurological or psychiatric diseases. In this review, we aimed to collect all available data on BDNF and bipolar disorder (BD) and assess if BDNF could be considered a biomarker for BD. We searched the most relevant medical databases and included studies reporting original data on BDNF circulating levels or Val66Met polymorphism. Only articles including a direct comparison with healthy controls (HC) and patients diagnosed with BD according to international classification systems were included. Of the 2430 identified articles, 29 were included in the present review. Results of the present review show a reduction in BDNF circulating levels during acute phases of BD compared to HC, which increase after effective therapy of the disorders. The Val66Met polymorphism was related to features usually associated with worse outcomes. High heterogeneity has been observed regarding sample size, clinical differences of included patients, and data analysis approaches, reducing comparisons among studies. Although more studies are needed, BDNF seems to be a promising biomarker for BD.

Biological correlates of treatment resistant depression: a review of peripheral biomarkers

“…The BDNF belongs to the family of neurotrophins, a group of growth factors that support the survival, development, and function of neurons in the brain and peripheral nervous system ( 78 ). Inflammation, which is associated with increased cytokines production, affects BDNF expression, although the exact biological pathway is not fully elucidated ( 79 ). Chronic stress induces a reduction in BDNF concentration ( 80 ), but studies analyzing serum BDNF levels in TRD conveyed conflicting results ( 81 ).…”