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

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.

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.

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.

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.