Serum Brain-derived neurotrophic factor (BDNF): the severity and symptomatic dimensions of depression.

INTRODUCTION: The aim of this study was to compare the concentration of serum Brain-derived neurotrophic factor (BDNF) in patients suffering from major depressive disorder (MDD) considering the severity of MDD episode defined by the Hamilton rating scale for depression (HAMD-17). The other aim was to research the connection between serum BDNF and the symptomatic dimensions of MDD. SUBJECTS AND METHODS: The study includes 139 participants with major depressive disorder (MDD). Diagnosis of MDD was set by DSM-IV-TR criteria. The severity of MDD was estimated with HAM-D-17 in the manner that mild episode was diagnosed if the score on HAMD-17 was up to 18, moderately severe 18-25 and severe over 25. Concentration of BDNF was determined by the ELISA method. RESULTS: This research could not find a difference in BDNF concentration considering the severity of the depressive disorder in groups suffering from mild, moderately severe and severe episodes of MDD (F=1.816; p=0.169). Factor analysis of HAMD-17 extracted four dimensions of depressive symptoms. None of the symptomatic dimensions was significantly related to BDNF concentration. CONCLUSION: Results of this study indicate that serum BDNF levels are not related to the severity of depression and its specific symptomatic dimensions. These findings support the idea of a complex relationship between BDNF concentration at the periphery and in the CNS.