The effect of electroconvulsive therapy on brain derived neurotrophic factor levels in depressed patients

Objectives: The therapeutic mechanism of electroconvulsive therapy (ECT) are not fully understood. Preliminary studies support the neurotrophic effect of ECT. The aims of this study was to investigate serum and plasma brain-derived neurotrophic factor (BDNF) levels of depressed patients and healty controls, the effects of ECT on serum and plasma BDNF levels in patients in relation to clinical outcome and its relationship to neurocognitive function.Methods: Serum BDNF (S-BDNF) levels were measured using an enzyme-linked immunosorbent assay (ELISA) method in 30 depressed patients and 33 healthy controls before ECT (T0), after ECT (T1) and one month after the end of ECT. Also, plasma BDNF (P-BDNF) levels were measured in subgroup of this population consisting 17 patients and 19 controls.Results: S-BDNF levels of patients were not different than those found in control subjects at T0 and no change occured between T0, T1 and T2 despite of prominent clinical improvement after ECT. On the contrary, P-BDNF levels of patients were significantly lower than those of control subjects at T0 and significant increase has been identified parallel with the clinical improvement between T0, T1 and T2. We did not find a significant association between BDNF levels and cognitive test score, even though patients performed signi ? cantly worse on all cognitive tests as compared to controls.Conclusion: This study suggests that P-BDNF supports neurotrophic hypothesis of depression and neurotrophic mechanism of ECT, and S-BDNF is a nonspesific trait marker of depression. Our study has limited cognitive tests focused on memory which may explain the lack of association between serum/plasma BDNF levels and neurocognitive function, even though cognitive performance in patients was overall signi ? cantly worse as compared to healthy controls.