It has been shown that a decreased BDNF expression underlies the stress and depression and, conversely, the use of antidepressants causes enhanced BDNF expression that could mediate the beneficial effects in the hippocampus and prefrontal cortex (Duman and Monteggia, 2006; Krishnan and Nestler, 2008). The gene discussed is BDNF; the disease is depressive symptom measurement.