Partial normalization of serum brain-derived neurotrophic factor in remitted patients after a major depressive episode.

We had previously reported decreased serum brain-derived neurotrophic factor (BDNF) levels in depressed patients. In the present study, we tested the hypothesis that antidepressant treatment would normalize serum BDNF levels, at least in a subgroup of patients. Major depressed patients (15 females and 11 males) diagnosed according to DSM-IV criteria and healthy controls (13 females and 13 males) participated in this study. Serum BDNF was assayed with the ELISA method for depressed and remitted patients and the severity of depression was evaluated with the Montgomery-Asberg Depression Rating Scale. An analysis of variance showed that treatment had an effect [F(1, 24) = 4.46, p = 0.045] on the normalization of serum BDNF levels. We also found a correlation between the severity of depression (r = 0.51, p = 0.008), the pretreatment BDNF levels (r = 0.62, p = 0.001) and the difference in serum BDNF levels after antidepressant treatment. These results suggest that antidepressant treatment has a positive effect on serum BDNF levels and support the hypothesis of neurotrophic factor involvement in affective disorders.