NTRK2 and major depressive disorder: This may be relevant to clinical interests, since colleagues from Dr. Kelsoe's group have shown that the rs1387923 polymorphism near NTRK2 is associated with the effectiveness of lithium in preventing relapses of bipolar disorder (many relapses are depressive episodes,) and NTRK2 alleles may be associated with suicide [19,23,24].