Vitamin D and depression: mechanisms, determination and application.

Depression is the most common debilitating psychiatric disease, the pathological mechanisms of which are associated with multiple aspects of neural function. While recent evidence has consistently suggested that a suboptimal vitamin D status is frequently observed in patients with depression, the results concerning whether vitamin D insufficiency is a causal factor of depression or is secondary to depressive behavior are conflicting; additionally, the lack of consistency of the method of vitamin D determination between labs has further worsened this confusion. Herein, we reviewed the neuroactivities of vitamin D that may be associated with depression and the current studies and clinical investigations to provide a full overview on the use of vitamin D in the treatment and prevention of depression.