Serum Brain-derived Neurotrophic Factor Level In Depressive Patients And Relative Analysis

Objective: The aim of this study was to explore the difference of serum brain-derived neurotrophic factor level in patients with major depressive disorder and dysthymia disorder ,and the relationship between serum brain-derived neurotrophic factor level and depressive symptoms.Methods: 24 patients with dysthymia, 36 patients with major depressive disorder and 27 subjects without any psychiatric diagnosis and any psychiatric treatment were included in the study. The severity of depression was assessed with 24-item HAMD. Blood samples were collected at baseline. Serum BDNF was kept at - 80℃before testing, and assayed with an ELISA Kit (BOSTER), after dilution with the Block and Sample solution provided with the kit.The data were subjected to the analysis of variance and the analysis of correlation.Results: The BDNF serum concentrations of dysthymia group was significantly higher than that of major depressive disorder group,(16.2±0.9 )ng/ml vs(12.45±1.20) ng/ml (P=0.003), and it was not different from the level of the control group, (16.2±0.9 ) ng/ml vs(17.21±1.31) ng/ml (P>0.05). The serum brain-derived neurotrophic factor level of depressive groups was significantly negatively correlated with duration(r=-0.456,P=0.002), negatively correlated with the HAMD₂₄ scores (r=-0.828, P=0.000).Furthermore,it was negatively correlated with the cognitive disturbance (r= -0.804,P=0.001) and diurnal varation (r=-0.644.P=0.018).In cognitive disturbance ,it was significantly negatively correlated with suicide (r=-0.807,P=0.001),but have no correlation with others(P>0.05).Conclusion :The low level of BDNF in patients with dysthymic disorder seems to point out that dysthymia and major depressive disorder are heterogeneous.It suggests BDNF may play a critical role in the suicidal behaviour of depressed patients that the serum brain-derived neurotrophic factor level of depressive groups were significantly negatively correlated with suicide,serum brain-derived neurotrophic factor level can act as one of the marker of suicide.