Estimated serum BDNF means (s.d.)at admission and upon discharge were 48.1(24.5) and 51.3(22.6) in major depression; 45.4 (17.7) and 48.4 (20.0) in bipolar depression; 42.5 (20.7) and 53.1 (25.1) in manic episode; and 46.5 (21.8) and 49.1 (19.0) in schizophrenia (Table 3). Here, BDNF is linked to bipolar disorder.