The study of brain-derived neurotrophic factor (BDNF) in mood disorders and other psychiatric disorders is increasing. Of particular interest is whether or not BDNF can be a marker for psychiatric disorders. The aim of this study was to review the published findings on BDNF in stress-related mood disorders. Searches were conducted of the PubMed and Psikiyatri Dizini databases to access international and national publications, respectively. Database searches were conducted with the keywords BDNF, and stress and mood disorders. BDNF plays a role in the physiopathology of stress-related changes and is supposedly related to a decrease in the number and size of neurons. Additionally, it has been suggested that serum levels of BDNF are lower in depressive patients than in the healthy controls. Nonetheless, BDNF levels increase after antidepressant treatment, along with symptom recovery, to those seen in healthy control subjects. This increase cannot be achieved in patients that do not respond to antidepressant treatment. On the other hand, in patients with stress-related non-depressive psychiatric disorders, serum BDNF is also low. To date, even though consistent findings of reduced BDNF levels have been reported, the specificity of these findings is doubtful. Serum BDNF might be considered a marker for stress-related mood disorders.