NTRK2 and alcohol dependence: The lymphocyte mRNA levels of BDNF (t = −2.804, P = 0.01, Student’s t-test; Fig. 1c) and TrkB (t = 5.733, P < 0.001, Student’s t-test; Fig. 1d) were significantly reduced in the alcohol dependence group (n = 28) compared to the control group (n = 46).