Although the pathophysiology of depression remains enigmatic, brain-derived neurotrophic factor (BDNF) and its specific receptor, tropomyosin-receptor-kinase B (TrkB), plays a key role in depression, as well as the therapeutic mechanisms of antidepressants20, 21, 22, 23, 24, 25, 26. This evidence concerns the gene BDNF and depressive symptom measurement.