Bipolar Disorder Research Roundup: December 1, 2023

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In this Research Roundup, we explore new studies on bipolar disorder, bipolar depression, and potential connections between the manic symptomatology in the disorder and vitamin D metabolites.

Sex-Specific Biomarkers for Anhedonia in Unipolar, Bipolar Depression
This study investigated sex-specific associations between immune-inflammatory markers, lipoprotein profiles, and anhedonia in 227 patients with unipolar and bipolar depression. Male patients in the anhedonia group exhibited higher levels of CD3, CD4, and CD8, and lower levels of Lp (a) compared with the non-anhedonia group, whereas no significant differences were observed in females. Logistic regression analysis suggested that CD3, CD4, CD8, and Lp (a) levels collectively served as a potential biomarker for identifying anhedonia in male patients with depression.

“These findings provide valuable insights for understanding sex-specific biomarkers and molecular mechanisms of anhedonia in patients with unipolar and bipolar depression,” the investigators concluded. “If verified, this study has considerable implications in precision medicine.”

Reference

Lin S, Liu R, Zhang Z, et al. Sex-specific immune-inflammatory markers and lipoprotein profile in patients with anhedonia with unipolar and bipolar depression. BMC Psychiatry. 2023;23(1):879.

Population Pharmacokinetics Models of Lithium for Bipolar Disorder
This study evaluated the clinical applicability of published population pharmacokinetic (popPK) models for lithium in the treatment of bipolar disorder. Testing these models on 2 external datasets revealed limited predictive performance, with most models showing a lack of predictability and underestimating observed concentrations. The absence of crucial covariates, such as renal status, in the majority of models highlights the need for improvement, potentially through methodologies like metamodeling for enhanced precision dosing in lithium treatment.

“Most of lithium’s PopPK models had limited predictive performances related to the absence of covariates of interest included, such as renal status,” the investigators concluded. “A solution to this problem could be to improve the models with methodologies such as metamodeling. This could be useful in the perspective of model-informed precision dosing.”

Reference

Aurélie L, Andréa B, Gauvind K, et al. External evaluation of population pharmacokinetics models of lithium in the bipolar population. Pharmaceuticals (Basel). 2023;16(11):1627.

Potential Connections Between Vitamin D Metabolites and Manic Symptomatology in Bipolar Disorder
In this cross-sectional study involving 170 outpatients with bipolar disorder (BD) and 138 healthy controls, the concentrations of vitamin D metabolites were analyzed, including 25(OH)D and 24,25(OH)2D, along with the vitamin D metabolite ratio (VMR). Although there were no significant differences in vitamin D levels between patients and controls, negative correlations were observed between the Young Mania Rating Scale and 24,25(OH)2D, as well as the VMR, suggesting a potential association between specific vitamin D metabolites and manic symptomatology in patients with BD.

“Based on the small effect size and the predominantly euthymic sample, further exploration in individuals with manic symptoms would be needed to confirm this association,” the investigators concluded. “In addition, long-term clinical markers and an assessment in different phases of the disease may provide additional insights.”

Reference

Späth Z, Tmava-Berisha A, Fellendorf FT, et al. Vitamin D status in bipolar disorder. Nutrients. 2023;15(22):4752.

Note: This Research Roundup was prepared with the assistance of ChatGPT.

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