mBDNF exerts biological effects on neurons by binding to its receptor tyrosine kinase B (TrkB), which subsequently elicits various intracellular signaling pathways, including mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MAPK/ERK), causing oxidative stress and inflammation in depression [9,10]. This evidence concerns the gene NTRK2 and depressive symptom measurement.