Differences Of Cognitive Impairment And Its Correlation With BDNF In First-diagnosed Depression And Bipolar Depression

Objective:The clinical symptoms of major depressive disorder(MDD)and depressive episodes of bipolar disorder(BD)are highly overlapping,and it is difficult to distinguish them.Comparing their differences in cognitive function is beneficial to distinguish the two diseases.In this study,we aim to explore the differences in cognitive function among MDD,BD patients and normal controls,as well as the relationships between serum brain-derived neurotrophic factor(BDNF)level and cognitive function.Method:This study is a cross-sectional study.A total of 82 first-diagnosed drug-naive patients with MDD,96 first-diagnosed drug-naive patients with BD,and 87 healthy controls were recruited.HAMD-17,YMRS were used to evaluate the clinical symptoms of the subjects,Repeatable Battery for the Assessment of Neuropsychological Status(RBANS)scale and Stroop color word test were used to evaluate the cognitive function of the subjects,and we detected serum BDNF levels in selected subjects.Statistical analysis was performed in SPSS25.Result:(1)Patients with MDD and BD have extensive cognitive dysfunction such as immediate memory,delayed memory,attention,visual span,executive function,etc.Attention deficits of patients with MDD is more severe than that of patients with BD(p=0.009).(2)Serum BDNF levels in the BD group is significantly lower than that in the MDD group(p=0.027)and the healthy control group(p=0.001),and there is no significant difference between the MDD group and the control group.(3)In the BD group,serum BDNF levels are positively correlated with visual span(r=0.379,p=0.010)and Stroop color words(r=0.333,p=0.027).In the MDD group,serum BDNF levels are positively correlated with language fluency(r=0.433,p=0.006).Conclusion:MDD and BD patients generally have extensive cognitive dysfunction,and the reduction of serum BDNF levels is associated with some cognitive deficits in MDD and BD patients.