Is BDNF biological link between depression and type 2 diabetes mellitus?

Epidemiological and clinical studies have demonstrated a strong association between depression and diabetes. Of note, depression is a risk factor for the development of type 2 diabetes mellitus (T2DM), while most patients with T2DM also have depression. Despite the abundance of evidence showing an epidemiological link between depression and T2DM, the cause of this association is still unknown. Brain-derived neurotrophic factor (BDNF) is widely expressed in the brain. Biological and clinical studies have repeatedly shown that BDNF is important in the pathogenesis of depression and T2DM. Therefore, we propose that BDNF may play an important role linking depression and T2DM. Studies examining the components of the BDNF system in patients with T2DM and depression may provide new understanding into the link between depression and T2DM. Such studies might also help us to identify potential treatment targets for these two common disorders.