The effect of adjunctive nutraceuticals in bipolar disorder: A systematic review of randomized placebo-controlled trials

Therapeutic Implications of the Microbial Hypothesis of Mental Illness

There is increasingly compelling evidence that microorganisms may play an etiological role in the emergence of mental illness in a subset of the population. Historically, most work has focused on the neurotrophic herpesviruses, herpes simplex virus type 1 (HSV-1), cytomegalovirus (CMV), and Epstein-Barr virus (EBV) as well as the protozoan, Toxoplasma gondii. In this chapter, we provide an umbrella review of this literature and additionally highlight prospective studies that allow more mechanistic conclusions to be drawn. Next, we focus on clinical trials of anti-microbial medications for the treatment of psychiatric disorders. We critically evaluate six trials that tested the impact of anti-herpes medications on inflammatory outcomes in the context of a medical disorder, nine clinical trials utilizing anti-herpetic medications for the treatment of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) or schizophrenia, and four clinical trials utilizing anti-parasitic medications for the treatment of schizophrenia. We then turn our attention to evidence for a gut dysbiosis and altered microbiome in psychiatric disorders, and the potential therapeutic effects of probiotics, including an analysis of more than 10 randomized controlled trials of probiotics in the context of schizophrenia, bipolar disorder (BD), and major depressive disorder (MDD).

The Effect of Adjunctive Probiotics on Markers of Inflammation and Oxidative Stress in Bipolar Disorder: A Double-blind, Randomized, Controlled Trial

BACKGROUND

Bipolar disorder (BD) is a chronic psychiatric illness. Concentrations of inflammatory cytokines are increased in BD. Supplementation with probiotics has shown promising effects in reducing inflammation and producing improvement in clinical symptoms in some psychiatric disorders. Therefore, we designed a clinical trial to assess the effects of adjunctive probiotics on markers of inflammation and oxidative stress in patients with BD.

METHODS

In this 8-week, double-blind, randomized study, 38 patients suffering from BD type I were given a probiotic or placebo capsule each day. Serum levels of interleukin-6 (IL-6), as the primary outcome measure, and of interleukin-10 (IL-10), tumor necrosis factor-α, and malondialdehyde, as the secondary outcome measures, were obtained before and after the intervention.

RESULTS

At the end of the study, the 2 groups showed no significant or clinically meaningful differences in the serum concentrations of IL-6 [Hedge g=0.02, 95% confidence interval (CI): -0.6; 0.64, P=0.936], tumor necrosis factor-α (Hedge g=-0.2, 95% CI: -0.82; 0.42, P=0.554), IL-10 (Hedge g=-0.072, 95% CI: -0.071; 0.56, P=0.827), and malondialdehyde (Hedge g=0.27, 95% CI: -0.37; 0.91, P=0.423).

CONCLUSIONS

This study did not find any significant or conclusive effects of probiotics supplementation on markers of inflammation and oxidative stress in patients with BD. Further studies are needed before a conclusion can be drawn about the efficacy of probiotics in the management of BD.

Effect of Probiotic Supplements on Oxidative Stress Biomarkers in First-Episode Bipolar Disorder Patients: A Randomized, Placebo-Controlled Trial

Background: Currently no study has examined the effects of probiotic administration on the symptoms of anxiety, depression, and mania, as well as their correlations with the biomarkers of oxidative stress in patients with bipolar disorder (BPD). The aim of this study is to determine the effects of probiotic supplementation on plasma oxidative stress-related biomarkers and different domains of clinical symptom in patients suffering from BPD.

Methods: Eighty first-episode drug-naive patients with BPD were recruited. The subjects were randomized to receive psychotropic drugs supplementing with either probiotic or placebo and scheduled to evaluate with follow-ups for clinical symptom improvements and changes in the oxidative stress biomarkers. The Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, and Young Mania Rating Scale were used to assess the clinical symptomatology. The panel of plasma oxidative stress biomarkers were determined by ultra-performance liquid chromatography–mass spectrometry (UPLC–MS/MS) at baseline and for 3 months of follow-up, i.e., at post-treatment month 1, 2, and 3.

Results: After 3 months of intervention, decreased levels of plasma lysophosphatidylcholines (LPCs) were found in both placebo and probiotic groups. However, six other oxidative stress biomarkers (i.e., creatine, inosine, hypoxanthine, choline, uric acid, allantoic acid) increased in BPD patients after the two types of therapies. In addition, a positive correlation between changes of LPC (18:0) and YMRS scale was found in BPD patients and this association only existed in the probiotic group. Additionally, the mania symptom greatly alleviated (pretreatment–posttreatment, odds ratio = 0.09, 95%CI = 0.01, 0.64, p= 0.016) in patients who received probiotic supplements as compared with the placebo group.

Conclusion: The changes in plasma biomarkers of oxidative stress in patients with BPD have a potential to be trait-like markers, and serve as prognostic indexes for bipolar patients. Daily intakes of probiotics have advantageous effects on BPD patients with certain clinical symptoms, especially manic symptoms. The treatment may be a promising adjunctive therapeutic strategy for BPD patients in manic episode.

Therapeutic Interventions to Mitigate Mitochondrial Dysfunction and Oxidative Stress–Induced Damage in Patients with Bipolar Disorder

Bipolar disorder (BD) is characterized by mood changes, including recurrent manic, hypomanic, and depressive episodes, which may involve mixed symptoms. Despite the progress in neurobiological research, the pathophysiology of BD has not been extensively described to date. Progress in the understanding of the neurobiology driving BD could help facilitate the discovery of therapeutic targets and biomarkers for its early detection. Oxidative stress (OS), which damages biomolecules and causes mitochondrial and dopamine system dysfunctions, is a persistent finding in patients with BD. Inflammation and immune dysfunction might also play a role in BD pathophysiology. Specific nutrient supplements (nutraceuticals) may target neurobiological pathways suggested to be perturbed in BD, such as inflammation, mitochondrial dysfunction, and OS. Consequently, nutraceuticals may be used in the adjunctive treatment of BD. This paper summarizes the possible roles of OS, mitochondrial dysfunction, and immune system dysregulation in the onset of BD. It then discusses OS-mitigating strategies that may serve as therapeutic interventions for BD. It also analyzes the relationship between diet and BD as well as the use of nutritional interventions in the treatment of BD. In addition, it addresses the use of lithium therapy; novel antipsychotic agents, including clozapine, olanzapine, risperidone, cariprazine, and quetiapine; and anti-inflammatory agents to treat BD. Furthermore, it reviews the efficacy of the most used therapies for BD, such as cognitive–behavioral therapy, bright light therapy, imagery-focused cognitive therapy, and electroconvulsive therapy. A better understanding of the roles of OS, mitochondrial dysfunction, and inflammation in the pathogenesis of bipolar disorder, along with a stronger elucidation of the therapeutic functions of antioxidants, antipsychotics, anti-inflammatory agents, lithium therapy, and light therapies, may lead to improved strategies for the treatment and prevention of bipolar disorder.

The Management of Prodromal Symptoms of Bipolar Disorder: Available Options and Future Perspectives

The onset of prodromal symptoms in subjects who are at familial or clinical risk for bipolar disorder could be considered as an important alarm bell for the development of the disease and should be carefully detected. The management of prodromes in bipolar high-risk patients appears to be an important means of prevention; nevertheless, at the moment, there aren’t clear and widely shared treatment indications. The aim of this review is to summarize the available treatment options (pharmacological, psychosocial and nutraceutical) for the management of prodromal symptoms in subjects who are at familial or clinical risk for bipolar disorder.

The effect of cocoa-rich products on depression, anxiety, and mood: A systematic review and meta-analysis

In the popular imaginary, cocoa-derived products, like chocolate, represent a panacea for mood and affectivity. However, whether this is a myth or a fact has yet to be clarified. A systematic review and meta-analysis were conducted according to the PRISMA guidelines to investigate the effect of cocoa-derived food on depressive and anxiety symptoms, positive and negative affect. We searched Web of Knowledge^TM and PsycINFO up to April 3, 2020. After screening 761 records, we selected nine studies. Two trials evaluated the long-term effects of cocoa consumption (>1 week), two studies the short-term effects (3 days), while five studies were conducted in acute (single administration). Random-effects meta-analyses found an overall significant effect of cocoa-rich products on depressive (Hedge's g = -0.42, 95% CI -0.67 to -0.17) and anxiety symptoms (Hedge's g = -0.49, 95% CI -0.78 to -0.19). Moreover, both positive (Hedge's g = 0.41, 95% CI 0.06 to 0.77) and negative affect (Hedge's g = -0.47, 95% CI -0.91 to -0.03) significantly improved. In all meta-analyses, the effect size was medium, while heterogeneity was low. Our findings suggest that the consumption of cocoa-rich products may improve affect and mood in the short term. However, given the short duration of trials, our results cannot be generalized to long-term intake of cocoa-derived food. Cautious interpretation is also needed due to the low number of participants and studies included in the meta-analyses.

Neutrophil-to-Lymphocyte Ratio, a Novel Inflammatory Marker, as a Predictor of Bipolar Type in Depressed Patients: A Quest for Biological Markers

(1) Background: Recent research suggests inflammation as a factor involved in the pathophysiology of mood disorders. Neutrophil-to-lymphocyte (NLR), monocyte-to-lymphocyte (MLR), platelet-to-lymphocyte (PLR), and systemic immune-inflammatory (SII) index ratios have been studied as peripheral markers of inflammation in bipolar and major depressive disorders. The purpose of this study is to comparatively analyze these inflammatory ratios among manic episodes of bipolar disorder, bipolar depression and unipolar depression. (2) Methods: 182 patients were retrospectively included in the study and divided into three groups: 65 manic patients, 34 patients with bipolar depression, and 83 unipolar depressive patients. White blood cells, neutrophils, monocytes, lymphocytes, and platelets were retrieved from the patients' database. NLR, MLR, PLR, and SII index were calculated using these parameters. (3) Results: Patients with manic episodes had elevated NLR (p < 0.001), MLR (p < 0.01), PLR (p < 0.05), and SII index (p < 0.001) compared to unipolar depression and increased NLR (p < 0.05) and SII index (p < 0.05) when compared to bipolar depression. NLR (p < 0.01) and SII index (p < 0.05) were higher in the bipolar depression than unipolar depression. NLR is an independent predictor of the bipolar type of depression in depressive patients. (4) Conclusions: The results confirm the role of inflammation in the pathophysiology of mood disorders and suggest the ability of NLR as a marker for the differentiation of bipolar from unipolar depression.

Gender Differences in Complete Blood Count and Inflammatory Ratios among Patients with Bipolar Disorder

Background: Evidence suggested that inflammation may be involved in the etiopathogenesis of bipolar disorder (BD), a chronic psychiatric condition affecting around 2–3% of the general population. However, little is known regarding potential gender differences in peripheral biomarkers of BD, such as neutrophil-to-lymphocyte (NLR), platelet-to-lymphocyte (PLR), and monocyte-to-lymphocyte (MLR) ratios. Methods: In total, 197 females and 174 males with BD in different phases (i.e., (hypo)mania, depression, euthymia) were recruited. A blood sample was drawn to perform a complete blood count (CBC). NLR, PLR, and MLR were subsequently calculated, and differences were computed according to the illness phase and gender. Results: PLR was consistently higher in (hypo)manic than depressed patients, in both males and females. No significant gender differences in PLR value were found when considering only (hypo)mania. Conversely, NLR was increased in (hypo)mania only among males, and gender differences were retrieved in the (hypo)manic subgroup. The findings related to MLR were only marginally significant. Higher platelets values were associated with (hypo)mania only in the female group. Basophils and eosinophils appeared gender- but not state-dependent. Conclusions: Our findings provide further evidence that increased PLR levels may be associated with (hypo)mania in bipolar patients, regardless of gender. Moreover, the usefulness of NLR as a peripheral biomarker of BD appeared limited to males while the role of platelets to females. As CBC represents a low-cost and easily accessible test, researchers should investigate in-depth its potential usefulness as a biomarker of BD and other psychiatric disorders.

The effects of psychobiotics on the microbiota-gut-brain axis in early-life stress and neuropsychiatric disorders

Psychobiotics are considered among potential avenues for modulating the bidirectional communication between the gastrointestinal tract and central nervous system, defined as the microbiota-gut-brain axis (MGBA). Even though causality has not yet been established, intestinal dysbiosis has emerged as a hallmark of several diseases, including neuropsychiatric disorders (NPDs). The fact that the microbiota and central nervous system are co-developing during the first years of life has provided a paradigm suggesting a potential role of psychobiotics for earlier interventions. Studies in animal models of early-life stress (ELS) have shown that they can counteract the pervasive effects of stress during this crucial developmental period, and rescue behavioral symptoms related to anxiety and depression later in life. In humans, evidence from clinical studies on the efficacy of psychobiotics at improving mental outcomes in most NPDs remain limited, except for major depressive disorder for which more studies are available. Consequently, the beneficial effect of psychobiotics on depression-related outcomes in adults are becoming clearer. While the specific mechanisms at play remain elusive, the effect of psychobiotics are generally considered to involve the hypothalamic-pituitary-adrenal axis, intestinal permeability, and inflammation. It is anticipated that future clinical studies will explore the potential role of psychobiotics at mitigating the risk developing NPDs in vulnerable individuals or in the context of childhood adversity. However, such studies remain challenging at present in terms of design and target populations; the profound impact of stress on the proper development of the MGBA during the first year of life is becoming increasingly recognized, but the trajectories post-ELS in humans and the mechanisms by which stress affects the susceptibility to various NPDs are still ill-defined. As psychobiotics are likely to exert both shared and specific mechanisms, a better definition of target subpopulations would allow to tailor psychobiotics selection by aligning mechanistic properties with known pathophysiological mechanisms or risk factors. Here we review the available evidence from clinical and preclinical studies supporting a role for psychobiotics at ameliorating depression-related outcomes, highlighting the knowledge gaps and challenges associated with conducting longitudinal studies to address outstanding key questions in the field.

A Systematic Review of Nutraceuticals for the Treatment of Bipolar Disorder

BACKGROUND

Certain nutrient supplements (nutraceuticals) may target neurobiological pathways perturbed in bipolar disorder (BD) such as inflammation, oxidative stress, and mitochondrial dysfunction. Nutraceuticals thus may have a potential role as adjunctive treatments for BD.

METHODS

A search of Embase via embase.com, PubMed via PubMed, Cumulated index to nursing and allied health literature (CINAHL) Complete via EBSCO, and Cochrane Central Register of Controlled Clinical Trials via cochranelibrary.com was conducted to identify published randomized controlled trials assessing the efficacy of nutraceuticals on mood symptomatology in adults with BD. Search terms for BD, nutraceuticals, and clinical trials (total search terms = 75) were used to search from inception to February 20, 2020. The Cochrane Collaboration's tool for assessing the risk of bias in randomized trials was used to assess the risk of bias.

RESULTS

A total of 1,712 studies were identified through the search. After rigorous screening, 22 studies were included in the review. There was large variability across the studies with 15 different nutraceutical agents assessed and as such insufficient homogeneity for a meta-analysis to be conducted (I² > 50%). Studies revealed promising, albeit conflicting, evidence for omega-3 fatty acids and N-acetylcysteine. Isolated positive results were reported for coenzyme Q10.

CONCLUSION

Given nutraceuticals are tolerable and accessible, they may be useful as potential adjunctive treatments for BD. Nutraceuticals targeting neuroinflammation or mitochondrial activity may have the most potential for the depressive phase. However, further studies are required to determine efficacy.

Mitochondrial dysfunction as a critical event in the pathophysiology of bipolar disorder

The understanding of the pathophysiology of bipolar disorder (BD) remains modest, despite recent advances in neurobiological research. The mitochondrial dysfunction hypothesis of bipolar disorder has been corroborated by several studies involving postmortem brain analysis, neuroimaging, and specific biomarkers in both rodent models and humans. Evidence suggests that BD might be related to abnormal mitochondrial morphology and dynamics, neuroimmune dysfunction, and atypical mitochondrial metabolism and oxidative stress pathways. Mitochondrial dysfunction in mood disorders is also associated with abnormal Ca2+ levels, glutamate excitotoxicity, an imbalance between pro- and antiapoptotic proteins towards apoptosis, abnormal gene expression of electron transport chain complexes, and decreased ATP synthesis. This paper aims to review and discuss the implications of mitochondrial dysfunction in BD etiology and to explore mitochondria as a potential target for novel therapeutic agents.

Neutrophil-to-Lymphocyte, Platelet-to-Lymphocyte and Monocyte-to-Lymphocyte Ratio in Bipolar Disorder

Background: Several inflammatory hypotheses have been suggested to explain the etiopathogenesis of bipolar disorder (BD) and its different phases. Neutrophil-to-lymphocyte (NLR), platelet-to-lymphocyte (PLR), and monocyte-to-lymphocyte (MLR) ratios have been proposed as potential peripheral biomarkers of mood episodes. Methods: We recruited 294 patients affected by BD, of which 143 were experiencing a (hypo)manic episode and 151 were in a depressive phase. A blood sample was drawn to perform a complete blood count. NLR, PLR, and MLR were subsequently calculated. A t-test was performed to evaluate differences in blood cell counts between depressed and (hypo)manic patients and a regression model was then computed. Results: Mean values of neutrophils, platelets, mean platelet volume, NLR, PLR, and MLR were significantly higher in (hypo)manic than depressed individuals. Logistic regression showed that PLR may represent an independent predictor of (hypo)mania. Conclusions: Altered inflammatory indexes, particularly PLR, may explain the onset and recurrence of (hypo)manic episodes in patients with BD. As inflammatory ratios represent economical and accessible markers of inflammation, further studies should be implemented to better elucidate their role as peripheral biomarkers of BD mood episodes.

Lipid and Glycemic Profiles in Patients with Bipolar Disorder: Cholesterol Levels Are Reduced in Mania

Background and Objectives: Bipolar disorder (BD) is a severe mental condition with a lifetime prevalence estimated around 2% among the general population. Due to risk factors, etiological mechanisms, and the chronic use of psychotropic medications, people with BD are frequently affected by medical comorbidities, such as metabolic syndrome (MetS), associated with altered blood levels of glucose, cholesterol, and triglycerides. Moreover, the lipid concentration may be associated with the severity of psychiatric symptoms. Materials and Methods: Five hundred and forty-two in- and outpatients (418 affected by BD and 124 affected by schizophrenia) were recruited in two Italian university hospitals. A blood examination assessing the fasting glucose, total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides was performed. Results: No significant differences were found in the lipid and glycemic profiles between patients with BD and schizophrenia. When considering only the BD sample, we found that patients experiencing a manic episode had significantly lower total cholesterol, HDL, and LDL than euthymic patients. Moreover, the total and LDL cholesterol levels were significantly lower in (hypo)manic than depressed patients. Mood episodes did not influence the triglyceride and glucose levels in our sample. Conclusions: Clinicians should pay attention to blood cholesterol levels in patients with BD, as differences in concentrations may predispose them to severe medical conditions and can be associated with the onset of mood episodes.

Diet and Neurocognition in Mood Disorders - An Overview of the Overlooked

Bipolar disorder and major depression are associated with significant disability, morbidity, and reduced life expectancy. People with mood disorders have shown higher ratios of unhealthy lifestyle choices, including poor diet quality and suboptimal nutrition. Diet and nutrition impact on brain /mental health, but cognitive outcomes have been less researched in psychiatric disorders. Neurocognitive dysfunction is a major driver of social dysfunction and a therapeutic target in mood disorders, although effective cognitive-enhancers are currently lacking. This narrative review aimed to assess the potential cognitive benefits of dietary and nutritional interventions in subjects diagnosed with mood disorders. Eight clinical trials with nutrients were identified, whereas none involved dietary interventions. Efficacy to improve select cognitive deficits has been reported, but results are either preliminary or inconsistent. Methodological recommendations for future cognition trials in the field are advanced. Current evidence and future views are discussed from the perspectives of precision medicine, clinical staging, nutritional psychiatry, and the brain-gut-microbiota axis.

Circulating exosomal microRNAs in bipolar disorder

INTRODUCTION

Emerging evidence suggests central roles of miRNAs in the pathogenesis of bipolar disorder (BD). Exosomes are membrane-bound vesicles acting as "biological cargo carriers" of various types of molecules including microRNAs. In this study, we aimed to investigate circulating exosomal microRNAs as potential diagnostic biomarkers for BD.

METHODS

The exosomes were precipitated from plasma samples of patients with BD (n = 69; 15 depressed, 27 manic, 27 euthymic) and healthy controls (n = 41). Total RNA was extracted from the exosomes and the levels of miRNAs were assayed by qPCR. Dysregulated miRNAs were subjected to Kyoto Encyclopedia of Genes and Genomes" (KEGG) pathway analysis by DIANA-miRPath v3.0 to identify the predicted targets and the related pathways.

RESULTS

Thirteen miRNAs showed significant differences between patients with BD and healthy individuals; among these, MiR-484, -652-3p, -142-3p remained significantly downregulated and miR-185-5p remained significantly upregulated after accounting for multiple comparisons and adjustments for potential confounders. There were no significant alterations among different states of BD. The KEEG analysis of four dysregulated miRNAs highlighted several target pathways including PI3K/Akt signaling, fatty acid biosynthesis/metabolism, extracellular matrix and adhesion pathways.

CONCLUSION

Our findings suggest that dysregulation of miRNAs might be involved in the underlying pathophysiology of BD through several biological pathways; and highlight the importance of the exosomal miRNAs for biomarker research in BD. Further longitudinal studies may clarify the roles of exosomal miRNAs and their targets in the neurobiology of BD.

Serum folate levels in bipolar disorder: a systematic review and meta-analysis

BACKGROUND

Bipolar disorder (BD) is a major psychiatric illness, however its physiopathology is unclear. The role of folate in the physiopathology of BD is controversial. We conducted this systematic review and meta-analysis to investigate the effect of folate in BD patients.

METHODS

We performed a thorough literature study of the PubMed, Embase, ScienceDirect, ClinicalKey, Cochrane Library, ProQuest, Web of Science, and ClinicalTrials.gov databases until December 21st, 2018. Random effects meta-analysis was conducted.

RESULTS

Six articles involving 481 patients with BD and 760 controls were included. The meta-analysis results suggested that serum folate levels in the patients with BD were significantly lower than those in the controls (Hedges' g = - 0.211, 95% confidence interval = - 0.391 to - 0.031, p = 0.021).

CONCLUSION

The current meta-analysis show it might be association between lower serum folate levels and patient with BD. However, we could not distinguish the potentially confounding effects of mood states on the folate levels. Further prospective studies including subjects with different mood states and possible physiopathology are warranted to investigate the association between folate deficiency and the etiology of BD.