The Spearman’s correlation test results showed that the serum level of mBDNF (n = 30, r = −0.438, P = 0.015, Fig. 4e) and the lymphocyte/serum level of TrkB (lymphocyte: n = 27, r = −0.394, P = 0.042, Fig. 4d; serum: n = 30, r = −0.398, P = 0.029, Fig. 4f) were negatively correlated with the daily ethanol consumption in the alcohol dependence group. Here, NTRK2 is linked to alcohol dependence.