Unconjugated bilirubin and acute psychosis: a five years retrospective observational and controlled study in patients with schizophrenia, schizoaffective and bipolar disorders

Investigating bilirubin concentrations in schizophrenia: A systematic review and meta-analysis

Schizophrenia, a severe mental disorder characterized by chronic disability and poor quality of life, has been shown to be associated with alterations in redox balance. Recent research has suggested a potential link between the antioxidant bilirubin and schizophrenia, although findings have been inconsistent. To address this gap, we conducted a systematic review and meta-analysis to evaluate possible alterations in bilirubin concentrations in schizophrenia. A comprehensive search of major databases was conducted to identify articles reporting total and unconjugated bilirubin in schizophrenic patients and healthy controls in case-control studies. Our meta-analysis included 18 studies investigating 16,245 participants. The pooled results did not reveal any significant association between schizophrenia and total bilirubin concentrations. Additionally, such effect was strongly influenced by the results of a single study in sensitivity analysis. Subgroup and meta-regression analyses based on various factors such as study design, sample size, and geographical region showed no significant associations with the effect size, nor they identified sources of heterogeneity. Furthermore, publication bias assessments were conducted to ensure the robustness of the findings. Overall, our findings summarize the available evidence regarding the possible role of bilirubin as a biomarker of schizophrenia and highlight the importance of conducting further research in this area.

The associations of psychopathology and metabolic parameters with serum bilirubin levels in patients with acute-episode and drug-free schizophrenia: a 5-year retrospective study using an electronic medical record system

BACKGROUND

The oxidative system plays an important role in the pathogenesis of schizophrenia. Inconsistent associations were found between hyperbilirubinemia and psychopathology as well as glycolipid metabolism in patients with schizophrenia at different episodes. This current study aimed to examine these associations in patients with acute-episode and drug-free (AEDF) schizophrenia.

METHODS

This is a retrospective study using 5 years of data from May 2017 to May 2022 extracted from the electronic medical record system of Chaohu Hospital of Anhui Medical University. Healthy controls (HCs) from the local medical screening center during the same period were also included. Participants' data of the bilirubin levels [total bilirubin (TB), conjugated bilirubin (CB), unconjugated bilirubin (UCB)], glycolipid metabolic parameters and the score of the Brief Psychiatric Rating Scale (BPRS) were collected.

RESULTS

A total of 1468 case records were identified through the initial search. After screening, 89 AEDF patients and 100 HCs were included. Compared with HCs, patients had a higher CB level, and lower levels of glycolipid metabolic parameters excluding high density lipoprotein-cholesterol (HDL-C) (all P < 0.001). Binary logistic regression analyses revealed that high bilirubin levels in the patients were independently associated with higher total and resistance subscale scores of BPRS, a higher HDL-C level, and lower total cholesterol and triglyceride levels (all P < 0.05).

CONCLUSION

Bilirubin levels are elevated in patients with AEDF schizophrenia. Patients with high bilirubin levels have more severe psychopathology and relatively optimized glycolipid metabolism. In clinical practice, regular monitoring of bilirubin levels in this patient population should be carried out.

Are There Any Differences in Clinical and Biochemical Variables between Bipolar Patients with or without Lifetime Psychotic Symptoms?

INTRODUCTION

Psychotic symptoms occur in more than half of patients affected by Bipolar Disorder (BD) and are associated with an unfavorable course of the disorder. The objective of this study is to identify the differences in the clinical and biochemical parameters between bipolar patients with or without psychotic symptoms.

METHODS

A total of 665 inpatients were recruited. Demographic, clinical, and biochemical data related to the first day of hospitalization were obtained via a screening of the clinical charts and intranet hospital applications. The two groups identified via the lifetime presence of psychotic symptoms were compared using t tests for quantitative variables and χ2 tests for qualitative ones; binary logistic regression models were subsequently performed.

RESULTS

Patients with psychotic BD (compared to non-psychotic ones) showed a longer duration of hospitalization (p < 0.001), higher Young Mania Rating Scale scores (p < 0.001), lower Global Assessment of Functioning scores (p = 0.002), a less frequent history of lifetime suicide attempts (p = 0.019), less achievement of remission during the current hospitalization (p = 0.028), and a higher Neutrophile to Lymphocyte Ratio (NLR) (p = 0.006), but lower total cholesterol (p = 0.018) and triglycerides (p = 0.013).

CONCLUSIONS

Patients with psychotic BD have a different clinical and biochemical profile compared to their counterparts, characterized by more clinical severity, fewer metabolic alterations, and a higher grade of inflammation. Further multi-center studies have to confirm the results of this present study.

Non-enzymatic antioxidants, macro-minerals and monocyte/high-density lipoprotein cholesterol ratio among patients with bipolar disorder

OBJECTIVE

Recent studies show that oxidative stress is related to the pathogenesis of BD. Non-enzymatic antioxidants, macro-minerals and MHR (monocyte divided by high-density lipoprotein cholesterol) participated oxidative stress and can be obtained quickly in hematological examination. This study used large-scale clinical data to investigate them between BD and healthy controls (HCs), as well as between psychotic and non-psychotic BD to explore their roles in disease progression.

METHODS

A total of 3442 BD-manic (BD-M) and 1405 BD-depression (BD-D) in acute stage and 5000 HCs were enrolled, including 1592 BD-M with psychotic symptoms (P-BD-M), 1850 BD-M without psychotic symptoms (NP-BD-M), 655 P-BD-D, 750 NP-BD-D. The differences in these biological parameter levels among different groups were compared, and the contributing factors for the occurrence of BD-M or BD-D and psychotic symptoms of BD were analyzed.

RESULTS

We found higher levels of Na and MHR, and lower levels of K, Ca and ALB in BD-M or BD-D compared with the HCs respectively; levels of K, Na, Ca, ALB and MHR have differences among P-BD-M, NP-BD-M and HC; levels of K, Na, Ca and ALB have differences among P-BD-D, NP-BD-D and HC. In multiple logistic regression, higher levels of MHR and Na were associated with BD-M; MHR was shown to be independently associated with P-BD-M; K, Na, ALB were shown to be independently associated with P-BD-D.

CONCLUSIONS

Our study highlights the role of oxidative stress in the pathophysiology of BD. There is heterogeneity between BD-M and BD-D, and different oxidative stress mechanisms of psychotic symptoms exist in BD-M and BD-D.

Relation Between Unconjugated Bilirubin and Peripheral Biomarkers of Inflammation Derived From Complete Blood Counts in Patients With Acute Stage of Schizophrenia

BACKGROUND

Inflammation and oxidative stress are the major leading hypothetical causes of schizophrenia. Unconjugated bilirubin (UCB) is an efficient endogenous plasma antioxidant. Inflammation is closely linked to oxidative stress. The relationship between UCB and inflammatory markers should be paid close attention in schizophrenia acute stage. In this paper, combined UCB and inflammatory markers were evaluated for their capability in predicting schizophrenia in the acute stage to find an easy and effective indicator to identify acute schizophrenia.

METHODS

A total of 6,937 acute schizophrenia patients and 6,404 healthy controls (HCs) were enrolled. UCB and peripheral biomarkers of inflammation derived from complete blood counts (CBC) were investigated in the subjects with acute schizophrenia, and the results were compared with HCs. Simultaneously, Spearman test was employed to assess the correlation between the variables, while logistic regression was adopted to determine the combined equation and receiver operating characteristic curve was used to evaluate the combined value of UCB and peripheral biomarkers of inflammation derived from CBC to predict schizophrenia in the acute stage.

RESULTS

The study indicates that white blood cells, neutrophil, monocyte, mean platelet volume (MPV), red cell distribution width (RDW), neutrophil/lymphocyte ratio (NLR), and monocyte/lymphocyte ratio (MLR) have significantly increased in schizophrenia (p < 0.05 for all), while platelet, lymphocyte, and platelet/lymphocyte ratio (PLR) in schizophrenia have significantly decreased (p < 0.05 for all). UCB exhibits negative correlation with MPV significantly (r = 0.121, p < 0.001), and no correlation with neutrophil and monocyte. The correlations between UCB and other peripheral biomarkers of inflammation derived from CBC are very weak. MPV, RDW, NLR, MLR, PLR, and UCB were taken as independent variables for a logistic regression analysis. The model was as follows: Logit  ( P 1 ) = - 6 . 141 + 0 . 827  MPV + 5 . 613  MLR - 0 . 005  PLR - 0 . 346  UBC . The combination demonstrates better effectiveness in predicting schizophrenia in the acute stage (AUC 0.831, 95% CI 0.825 to 0.837).

CONCLUSION

UCB has a protective effect on acute stage of schizophrenia, which is weak and indirect by affecting the proinflammatory processes. Our findings suggest that a combination of MLR, MPV, PLR, and UBC could be used to predict acute stage of schizophrenia.

Plasma bilirubin levels are reduced in first-episode psychosis patients and associates to working memory and duration of untreated psychosis

Schizophrenia is a severe mental disorder and one of its characteristics is cognitive impairments. Findings regarding levels of the heme metabolite and plasma antioxidant bilirubin in schizophrenia are inconclusive. However, a recently published study indicate that low levels of bilirubin may be implicated in the memory impairments seen in the disorder. The aim of this cross-sectional study was to investigate the levels of bilirubin in individuals with a first-episode psychosis (FEP) and to examine if bilirubin levels were associated to cognitive impairments, symptoms and duration of untreated psychosis (DUP). Bilirubin levels were reduced in 39 individuals with FEP compared with 20 HC (median [IQR]: 11.0 [9.0-13.0] µM vs. 15.0 [11.5-18.5] µM). In individuals with FEP, bilirubin levels were also positively correlated to two working memory tests (r = 0.40 and r = 0.32) and inversely correlated to DUP (r = - 0.36). Findings were not influenced by confounding factors. The results confirm the antioxidant deficit previously seen in schizophrenia, but also indicate that these changes may be related to DUP. The study also confirms that bilirubin may be implicated in the cognitive deficits that accompanies the disorder, here for the first time presented in individuals with FEP.

The Role of Bilirubin and the Other "Yellow Players" in Neurodegenerative Diseases

Bilirubin is a yellow endogenous derivate of the heme catabolism. Since the 1980s, it has been recognized as one of the most potent antioxidants in nature, able to counteract 10,000× higher intracellular concentrations of H2O2. In the recent years, not only bilirubin, but also its precursor biliverdin, and the enzymes involved in their productions (namely heme oxygenase and biliverdin reductase; altogether the "yellow players"-YPs) have been recognized playing a protective role in diseases characterized by a chronic prooxidant status. Based on that, there is an ongoing effort in inducing their activity as a therapeutic option. Nevertheless, the understanding of their specific contributions to pathological conditions of the central nervous system (CNS) and their role in these diseases are limited. In this review, we will focus on the most recent evidence linking the role of the YPs specifically to neurodegenerative and neurological conditions. Both the protective, as well as potentially worsening effects of the YP's activity will be discussed.