Objective     To study the correlation between trait anxiety and serum brain-derived neurotrophic factor（BDNF）level in patients with combined anxiety and depression and analyze whether trait anxiety affects the therapeutic effect in such patients.      Methods     Sixty-four patients with combined anxiety and depression and 60 normal controls were enrolled in this study. Patients with combined anxiety and depression were treated with paroxetine or sertraline and their trait anxiety was assessed with the trait anxiety inventory (T-AI) scale in the state-trait anxiety inventory (S-TAI）before and 2

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12 weeks after treatment. Serum BDNF levels in patients with combined anxiety and depression and normal controls were measured by ELISA and analyzed using the SPSS18.0.      Results     The serum BDNF levels were lower and the trait anxiety scores were higher in patients with combined anxiety and depression than in normal controls before treatment（P0.05）. The recovery time of serum BDNF levels was longer in patients with combined anxiety and depression who had abnormal T-AI scores than in those who had normal T-AI scores（P0.05）. The trait anxiety in patients with combined depression and anxiety was negatively correlated with their serum BDNF levels（r=-0.502，P0.05）.      Conclusion     Trait anxiety in patients with combined depression and anxiety is negatively correlated with their serum BDNF levels and the action of drugs in them is relatively later.