Correlations between brain-derived neurotrophic factor and clinical symptoms in medicated patients with major depression

Abstract

Brain-derived neurotrophic factor (BDNF) is a member of the nerve growth factor family and plays a critical role in growth, differentiation, maintenance and synaptic plasticity of neuronal systems. Previous studies have demonstrated lower serum BDNF concentrations in major depressive disorder (MDD), with concentrations negatively correlating with the severity of the disease. However, few investigations have examined the relationship between serum BDNF and detailed clinical symptoms. The aim of present study was to clarify the magnitudes of the relationships between various depressive symptom and serum BDNF. Serum BDNF concentrations were evaluated from 109 inpatients with MDD and 163 healthy controls. Depressive symptoms were assessed using the Hamilton rating scale for depression (HAM-D), and symptoms were categorized into four groups: "anxiety somatization"; "cognitive disturbance"; "retardation"; and "sleep disturbance". Serum BDNF concentration was significantly lower in patients with MDD compared to controls (p<0.001). We identified significant negative correlations between serum BDNF concentration and both total score (R=-0.19, p=0.044) and "anxiety somatization" sub-score (R=-0.32, p=0.001) from the HAM-D in patients with MDD. All patients in the present study were on antidepressant medications. These results suggest that serum BDNF level may offer a biological marker for anxiety symptoms in medicated patients with MDD.