The levels of the six serum proteins (tPA, PAI-1, BDNF, proBDNF, TrkB and p75NTR) and the value of BDNF/proBDNF in SZ, MDD, BM, BD and PD patients and HCs were shown in Figs 1 and 2. The gene discussed is NGFR; the disease is major depressive disorder.