Differences in verbal and spatial working memory in patients with bipolar II and unipolar depression: an MSI study

Background Depressive symptoms could be similarly expressed in bipolar and unipolar disorder. However, changes in cognition and brain networks might be quite distinct. We aimed to find out the difference in the neural mechanism of impaired working memory in patients with bipolar and unipolar disorder. Method According to diagnostic criteria of bipolar II disorder of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and assessments, 13 bipolar II depression (BP II), 8 unipolar depression (UD) patients and 15 healthy controls (HC) were recruited in the study. We used 2-back tasks and magnetic source imaging (MSI) to test working memory functions and get the brain reactions of the participants. Results Compared with HC, only spatial working memory tasks accuracy was significantly worse in both UD and BP II (p = 0.001). Pearson correlation showed that the stronger the FCs’ strength of MFG-IPL and IPL-preSMA, the higher accuracy of SWM task within left FPN in patients with UD (r = 0.860, p = 0.006; r = 0.752, p = 0.031). However, the FC strength of IFG-IPL was negatively correlated with the accuracy of SWM task within left FPN in patients with BP II (r = − 0.591, p = 0.033). Conclusions Our study showed that the spatial working memory of patients with whether UD or BP II was impaired. The patterns of FCs within these two groups of patients were different when performing working memory tasks.

Peripheral Uric Acid as a Biomarker in Individuals With Bipolar Disorder: A Case Control Study

Background: At present, no well-established biomarkers were ever found to distinguish unipolar disorder (UD) and bipolar disorder (BD). This study aimed to explore whether uric acid (UA) could be a biomarker to distinguish UD and BD. Methods: Peripheral UA of 119 patients with BD in acute stage (AS) and 77 in remission stage (RS), and 95 patients with UD in AS and 61 in RS were measured, so were 180 healthy controls. Differences in continuous variables among groups were assessed by the independent samples t-test and one-way analysis of variance. The chi-square test was applied to categorical data such as gender. Results: UA levels in BD group were higher than UD and HC groups regardless of the AS or RS, while differences in UA levels between UD group and HC group were not significant. Differences of UA levels between BD-M (bipolar mania/hypomania) and BD-D (bipolar depression) subgroups were not significant, and UA levels of BD-M and BD-D subgroups were higher than UD and HC groups. Only in UD group, UA levels of drug-use subgroup were higher than drug-naïve/free subgroup, but differences disappeared when analyzed stratified by sex; whether in drug-use or drug-naïve/free subgroup, differences of UA levels between BD-M and BD-D groups were not significant.Conclusion: The study suggests UA levels may be a biomarker of BD to distinguish from UD.

Peripheral Uric Acid as a Biomarker in Individuals with Bipolar Disorder

Background: At present, no well-established biomarkers were ever found to distinguish unipolar disorder (UD) and bipolar disorder (BD). This study aimed to explore whether uric acid (UA) could be a biomarker to distinguish UD and BD. Methods: Peripheral UA of 119 patients with BD in acute stage (AS) and 77 in remission stage (RS), and 95 patients with UD in AS and 61 in RS were measured, so were 180 healthy controls. Results: UA levels in BD group were higher than UD and HC groups regardless of the AS or RS, while differences in UA levels between UD group and HC group were not significant. Differences of UA levels between BD-M and BD-D subgroups were not significant, and UA levels of BD-M and BD-D subgroups were higher than UD and HC groups. Only in UD group, UA levels of drug-use subgroup were higher than drug-naïve/free subgroup, but differences disappeared when analyzed stratified by sex; whether in drug-use or drug-naïve/free subgroup, differences of UA levels between BD-M and BD-D groups were not significant.Conclusion: The study suggests UA levels may be a biomarker of BD to distinguish from UD.