Differences Of Brain-Derived Neurotrophic Factor In Patients With Common Mental Disorders

Objective: To investigate the diffenences of serum levels of brain-derived neurotrophic factor(BDNF) in patients with depression and schizophrenia, and provide evidence for clinical reasearch of those mechanisms and the possibility of BDNF as an effective biological marker of depression and schizophrenia.Methods: 48 patients with depression were enrolled and severity assessments were performed with Hamilton Depression Scale(HAMD) and Hamilton Anxiety Scale(HAMA), eliminating depression patients associated with anxiety disorders; 44 patients with schizophrenia were enrolled and severity assessments were performed with Positive and Negative Syndrome Scale (PANSS). Serum samples were collected from normal controls and patients with depression and schizophrenia and BDNF levels were doubly detected by ELISA. All data were analyzed by SPSS18.0.Results: (1)Serum BDNF levels of patients with depression and schizophrenia were lower than those of normal controls(P<0.01; P<0.01); (2)No statistical difference of BDNF levels was observed between patients with depression and schizophrenia(P>0.05), but serum BDNF levels of the latter were lower than those of the other;(3)Duration and HAMD scores of patients with depression were negatively correlated with serum BDNF levels(r= -0.43, P<0.01; r= -0.57, P<0.01), sex showed no effect on serum BDNF levels(P>0.05), and serum BDNF levels had little correlation with age(r=0.287, P<0.05); (4)No significant relations between duration, PANSS scores and BDNF levels were observed among patients with schizophrenia(r= -0.10, P>0.05; r=0.08, P>0.05).Conclusion: (1) Serum BDNF levels are lower in both patients with depression and schizophrenia than those in normal controls, thus they can be considered as one optional index in differential diagnosis of depression and schizophrenia; (2) No obvious difference was observed in serum BDNF levels between patients with depression and schizophrenia, but serum BDNF levels of the latter were lower than those of the other and further research with larger sample size may be warranted before serum BDNF levels used in differential diagnosis of depression and schizophrenia; (3) Our study shows that serum BDNF levels of patients with depression vary from 6-19ng/ml, while these levels vary from 4-18ng/ml in patients with schizophrenia, and a multinational multicentre research will be necessary to determine the range of serum BDNF levels used in differential diagnosis of depression and schizophrenia.