Changes of Serum Concentrations of Brain-Derived Neurotrophic Factor (BDNF) during Treatment with Venlafaxine and Mirtazapine: Role of Medication and Response to Treatment

Introduction: Depression, stress and antidepressant treatment have been found to modulate the expression of brain-derived neurotrophic factor (BDNF). Recent research suggests that serum BDNF concentration is reduced in depression and that antidepressant treatment leads to an increase in serum BDNF concentration. Methods: We studied depressed patients receiving a randomized antidepressant treatment with either mirtazapine (n = 29) or venlafaxine (n = 27) for 28 days in a prospective design. Changes in the concentrations of serum neurotrophins in response to antidepressant treatment were assessed. Results: There was a significant treatment by medication interaction effect on BDNF serum concentrations that indicated a decline of BDNF in venlafaxine-treated patients (7.82 +/- 3.75-7.18 +/- 5.64 ng/ml), while there was an increase in mirtazapine-treated patients (7.64 +/- 6.23-8.50 +/- 5.37 ng/ml). There was a trend for a treatment by remission interaction with a favourable clinical course being related to increasing serum BDNF. Discussion: Changes in BDNF serum concentrations as a result of antidepressant therapy depend on the antidepressant and potentially on the clinical course.