Notably, reduced levels of BDNF are among the most prevalent and effective biomarkers for depression [117], while the upregulation of BDNF mRNA expression in the HIP and cortex resembles the antidepressant response observed with traditional antidepressants such as selective serotonin reuptake inhibitors (SSRIs) [118]. The gene discussed is BDNF; the disease is major depressive disorder.