The Effects of Probiotic and Selenium Co-supplementation on Clinical and Metabolic Scales in Chronic Schizophrenia: a Randomized, Double-blind, Placebo-Controlled Trial

Ferroptosis in schizophrenia: Mechanisms and therapeutic potentials (Review)

Schizophrenia, a complex psychiatric disorder, presents with multifaceted symptoms and important challenges in treatment, primarily due to its pathophysiological complexity, which involves oxidative stress and aberrant iron metabolism. Recent insights into ferroptosis, a unique form of iron‑dependent cell death characterized by lipid peroxidation and antioxidant system failures, open new avenues for understanding the neurobiological foundation of schizophrenia. The present review explores the interplay between ferroptosis and schizophrenia, emphasizing the potential contributions of disrupted iron homeostasis and oxidative mechanisms to the pathology and progression of this disease. The emerging evidence linking ferroptosis with the oxidative stress observed in schizophrenia provides a compelling narrative for re‑evaluating current therapeutic strategies and exploring novel interventions targeting these molecular pathways, such as the glutathione peroxidase 4 pathway and the ferroptosis suppressor protein 1 pathway. By integrating recent advances in ferroptosis research, the current review highlights innovative therapeutic potentials, including N‑acetylcysteine, selenium, omega‑3 fatty acids and iron chelation therapy, which could address the limitations of existing treatments and improve clinical outcomes for individuals with schizophrenia.

Dysbiosis is associated with the behavioral phenotype observed in the triple-hit Wisket rat model of schizophrenia

Comorbidities between gastrointestinal diseases and psychiatric disorders have been widely reported, with the gut-brain axis implicated as a potential biological basis. Thus, dysbiosis may play an important role in the etiology of schizophrenia, which is barely detected. Triple-hit Wisket model rats exhibit various schizophrenia-like behavioral phenotypes. The present study aimed to compare the diversity and abundance of gut microbiota in Wisket model and control rats; furthermore, to correlate the microbial taxonomic profiles to indices of behavioral change. Tail-flick and Ambitus tests were used to assess acute heat pain sensitivity, and record exploration and locomotor activity along with motivation in young adult, control and Wisket model rats. Fecal microbiota composition was profiled by deep sequencing of bacterial 16S rRNA, and it was correlated to behavioral phenotype. Wisket rats exhibited significantly decreased pain sensitivity, lower locomotor activity and exploration, and impaired motivation compared with controls. No significant differences were observed in bacterial alpha diversity between the groups; however, clear differences in community structure were observed. Wisket rats showed decreases in several genera of Firmicutes and Saccharimonas, and increases in Bacteriodetes and Helicobacter phyla compared with controls. Correlation analysis revealed significant associations between the microbiota profile and the behavioral phenotype. This is the first demonstration that fecal microbiota composition is markedly altered in a triple-hit schizophrenia rat model, suggesting the contribution of the microbiota-gut-brain axis in the development of the schizophrenia-like behavioral phenotype. Thus targeting the gut microbiota may be a novel approach to treat such impairments.

Impact of probiotic treatment on clinical symptom reduction in schizophrenia: A systematic review and meta-analysis

INTRODUCTION

Recent research has identified gut microbiota dysbiosis as a potential contributing factor in schizophrenia, leading to growing interest in exploring probiotics as a complementary approach to traditional antipsychotic treatments. This study aims to systematically evaluate the current evidence on the efficacy of probiotics in improving clinical symptoms of schizophrenia, offering a novel perspective into their potential role as an adjunctive strategy.

METHODS

A systematic search was conducted to review randomized clinical trials, adhering to the PRISMA guidelines. A meta-analysis was also performed to assess the primary outcome, which was the impact of probiotic supplementation on clinical symptoms measured by the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Of the 76 studies initially identified, 5 were finally included. Regarding the symptomatology measured through the PANSS total score, the average effect was significant after the probiotic supplementation (standardized mean difference [SMD] = -0.608, (95% CI -1.314; -0.047), p = .035.

CONCLUSION

The synthesis of available data suggests that probiotic supplementation may effectively reduce clinical symptoms in schizophrenia. However, the limited number of studies prevents the formation of robust conclusions. Further clinical trials with more rigorous experimental designs are necessary before making definitive recommendations.

Effect of Probiotics on C-Reactive Protein Levels in Schizophrenia: Evidence from a Systematic Review and Meta-Analysis

BACKGROUND

Inflammatory markers play a pivotal role in schizophrenia, as they provide insight into the neuroinflammatory processes occurring in the context of the disorder. Elevated levels of these markers, particularly C-reactive protein (CRP), can indicate an underlying immune system dysregulation, potentially influencing symptom severity and progression. Recognizing these markers has led to investigate the use of probiotics as an adjuvant to improve the treatment of schizophrenia. The main objective of this study is to rigorously evaluate the efficacy of probiotics in reducing plasma levels of CRP in patients with schizophrenia.

METHODS

A systematic search and meta-analysis were conducted to review randomized clinical trials following the PRISMA methodology. The following search strategy ((SCHIZO* OR PSYCHOTIC OR PSYCHOSES) AND (PROBIOTIC* OR BIFIDOBACTER* OR LACTOBACILL*)) was used for searching publications between June-December 2024 on the PubMed, Web of Science, and APA PsycINFO databases. Individual study quality was assessed with the Cochrane risk of bias (RoB2) and the certainty of total evidence was assessed with the GRADE system.

RESULTS

The primary outcome assessed was the impact of probiotic supplementation on plasma CRP levels. Out of 78 studies initially identified, 4 were finally included in the meta-analysis. Three out four studies found a significant reduction in high-sensitivity C-reactive protein levels in the supplemented compared with the placebo group. The pooled analysis revealed a significant reduction in CRP levels with probiotic supplementation, with a standardized mean difference (SMD) of -0.46, (95% CI -0.719; -0.201; p = 0.001).

CONCLUSIONS

The synthesis and meta-analysis of available literature provide evidence for the potential role of probiotics in the reduction of serum CRP in schizophrenia compared with placebo. However, more clinical trials with better control of experimental design are needed before a clear recommendation as adjuvant therapy can be made.

Nutraceuticals and phytoceuticals in the treatment of schizophrenia: a systematic review and network meta-analysis "Nutra NMA SCZ"

Sub-optimal response in schizophrenia is frequent, warranting augmentation strategies over treatment-as-usual (TAU). We assessed nutraceuticals/phytoceutical augmentation strategies via network meta-analysis. Randomized controlled trials in schizophrenia/schizoaffective disorder were identified via the following databases: PubMed, MEDLINE, EMBASE, Scopus, PsycINFO, CENTRAL, and ClinicalTrials.gov. Change (Standardized Mean Difference = SMD) in total symptomatology and acceptability (Risk Ratio = RR) were co-primary outcomes. Secondary outcomes were positive, negative, cognitive, and depressive symptom changes, general psychopathology, tolerability, and response rates. We conducted subset analyses by disease phase and sensitivity analyses by risk of bias and assessed global/local inconsistency, publication bias, risk of bias, and confidence in the evidence. The systematic review included 49 records documenting 50 studies (n = 2384) documenting 22 interventions. Citicoline (SMD =-1.05,95%CI = -1.85; -0.24), L-lysine (SMD = -1.04,95%CI = -1.84; -0.25), N-acetylcysteine (SMD = -0.87, 95%CI = -1.27; -0.47) and sarcosine (SMD = -0.5,95%CI = -0.87-0.13) outperformed placebo for total symptomatology. High heterogeneity (tau2 = 0.10, I2 = 55.9%) and global inconsistency (Q = 40.79, df = 18, p = 0.002) emerged without publication bias (Egger's test, p = 0.42). Sarcosine improved negative symptoms (SMD = -0.65, 95%CI = -1.10; -0.19). N-acetylcysteine improved negative symptoms (SMD = -0.90, 95%CI = -1.42; -0.39)/general psychopathology (SMD = -0.76, 95%CI = -1.39; -0.13). No compound improved total symptomatology within acute phase studies (k = 7, n = 422). Sarcosine (SMD = -1.26,95%CI = -1.91; -0.60), citicoline (SMD = -1.05,95%CI = -1.65;-0.44), and N-acetylcysteine (SMD = -0.55,95%CI = -0.92,-0.19) outperformed placebo augmentation in clinically stable participants. Sensitivity analyses removing high-risk-of-bias studies confirmed overall findings in all phases and clinically stable samples. In contrast, the acute phase analysis restricted to low risk-of-bias studies showed a superior effect vs. placebo for N-acetylcysteine (SMD = -1.10, 95%CI = -1.75,-0.45), L-lysine (SMD = -1.05,95%CI = -1.55, -0.19), omega-3 fatty acids (SMD = -0.83,95%CI = -1.31, -0.34) and withania somnifera (SMD = -0.71,95%CI = -1.21,-0.22). Citicoline (SMD = -1.05,95%CI = -1.86,-0.23), L-lysine (SMD = -1.04,95%CI = -1.84,-0.24), N-acetylcysteine (SMD = -0.89,95%CI = -1.35,-0.43) and sarcosine (SMD = -0.61,95%CI = -1.02,-0.21) outperformed placebo augmentation of TAU ("any phase"). Drop-out due to any cause or adverse events did not differ between nutraceutical/phytoceutical vs. placebo+TAU. Sarcosine, citicoline, and N-acetylcysteine are promising augmentation interventions in stable patients with schizophrenia, yet the quality of evidence is low to very low. Further high-quality trials in acute phases/specific outcomes/difficult-to-treat schizophrenia are warranted.

IUPHAR themed review: The gut microbiome in schizophrenia

Gut microbial dysbiosis or altered gut microbial consortium, in schizophrenia suggests a pathogenic role through the gut-brain axis, influencing neuroinflammatory and neurotransmitter pathways critical to psychotic, affective, and cognitive symptoms. Paradoxically, conventional psychotropic interventions may exacerbate this dysbiosis, with antipsychotics, particularly olanzapine, demonstrating profound effects on microbial architecture through disruption of bacterial phyla ratios, diminished taxonomic diversity, and attenuated short-chain fatty acid synthesis. To address these challenges, novel therapeutic strategies targeting the gut microbiome, encompassing probiotic supplementation, prebiotic compounds, faecal microbiota transplantation, and rationalised co-pharmacotherapy, show promise in attenuating antipsychotic-induced metabolic disruptions while enhancing therapeutic efficacy. Harnessing such insights, precision medicine approaches promise to transform antipsychotic prescribing practices by identifying patients at risk of metabolic side effects based on their microbial profiles. This IUPHAR review collates the current literature landscape of the gut-brain axis and its intricate relationship with schizophrenia while advocating for integrating microbiome assessments and therapeutic management. Such a fundamental shift in proposing microbiome-informed psychotropic prescriptions to optimise therapeutic efficacy and reduce adverse metabolic impacts would align antipsychotic treatments with microbiome safety, prioritising 'gut-neutral' or gut-favourable drugs to safeguard long-term patient outcomes in schizophrenia therapy.

The efficacy of Lactobacillus and Bifidobacterium in patients with schizophrenia: a meta-analysis

The modulation of gut microbiota through probiotics holds promise as a novel avenue for schizophrenia treatment. This study aims to analyze probiotic complementary therapy on individuals with schizophrenia systematically, to investigate probiotic efficacy, potential mechanisms, and implications for clinical practice. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched in Medline, Web of Science, Embase, ClinicalTrials.gov, CNKI, VIP, and WanFang databases using keywords ("probiotics" OR "prebiotics" OR "synbiotics" OR "Lactobacillus" OR "Bifidobacterium") AND ("schizophrenia"), focused on randomized controlled trials published before July 1, 2023. Among the identified studies, 8 randomized controlled trials met the inclusion criteria, encompassing a total of 342 participants in the intervention group and 306 participants in the control group. Our analysis revealed a statistically significant reduction (p = 0.03) in the total Positive and Negative Syndrome Scale (PANSS) scores following probiotic treatment in individuals with schizophrenia. While no statistical significance was observed in individual subscales (P > 0.05), significant improvements were noted in insulin levels, Insulin Resistance Index (IRI), and glucose levels. Additionally, the Quantitative Insulin Sensitivity Check Index (QUICKI) demonstrated a significant increase (all P < 0.05). The probiotic intervention significantly reduced gastrointestinal discomfort among schizophrenia patients (P = 0.003). This study suggests that probiotics could hold therapeutic potential for addressing clinical symptoms, abnormal glucose metabolism, and gastrointestinal discomfort in individuals with schizophrenia. Future research should encompass comparative trials employing robust experimental designs to explore the differential effects of various probiotic strains on schizophrenia treatment to provide evidence-based therapeutic approaches. TRIAL REGISTRATION: This review protocol was pre-registered on PROSPERO (No. CRD42023455273).

Probiotic Formulation for Patients With Bipolar or Schizophrenia Spectrum Disorder: A Double-Blind, Randomized Placebo-Controlled Trial

BACKGROUND AND HYPOTHESIS

Probiotic augmentation offers a promising treatment for bipolar disorder (BD) and schizophrenia spectrum disorder (SSD). By targeting microbiome deviations, they may improve both gut and brain health.

STUDY DESIGN

In this double-blind, randomized, placebo-controlled trial with the multi-strain probiotic formulation Ecologic BARRIER, we aimed to improve psychiatric and cognitive symptoms, intestinal permeability, and gastrointestinal symptoms in patients with BD or SSD. A total of 131 patients were randomized 1:1 to receive either the probiotic supplement (n = 67) or a placebo (n = 64) for 3 months, in addition to treatment-as-usual. The primary outcomes were symptom severity assessed by the Brief Psychiatric Rating Scale and cognitive functioning by the Brief Assessment of Cognition in Schizophrenia.

STUDY RESULTS

No significant effect of probiotics was observed on psychiatric symptoms, but borderline significant improvement was observed in the cognition category of verbal memory (Linear Mixed Model (LMM) 0.33; adjusted P = .059). Probiotics beneficially affected markers of intestinal permeability and inflammation, including zonulin (LMMserum = -18.40; adjusted P = .002; LMMfecal = -10.47; adjusted P = .014) and alpha-1 antitrypsin (LMM 9.26; adjusted P = .025). Indigestion complaints significantly decreased in male participants in the probiotics group (LMM = -0.70; adjusted P = .010). Adverse events were similar between groups.

CONCLUSIONS

Our study observed significant advantages of probiotics for gut health in BD and SSD, with excellent safety and tolerability. A borderline effect on verbal memory was also indicated. These results underscore the need for further research into microbiome-targeted interventions for patients with complex brain disorders.

Using Selenium-enriched Mutated Probiotics as Enhancer for Fertility Parameters in Mice

Increasing fertility rates have become one of the factors that concern all people in the world. Therefore, the study aims to use two mutated strains of probiotics enriched with selenium (PSe40/60/1 and BSe50/20/1) to improve fertility. Thirty Swiss albino male mice were divided into three groups; control, LP + S was given Lactobacillus plantarum PSe40/60/1 plus selenium, and BL + S was given Bifidobacterium longum BSe50/20/1 plus selenium. Free testosterone, LH, and FSH were measured in serum by biochemical analysis. Testicular tissues were examined by histopathological analysis. The count and motility of sperm, and sperm abnormalities were determined by microscopic examination. The method of qRT-PCR was used to detect gene expression of Tspyl1, Hsd3b6, and Star genes. The biochemical results showed that serum content of free testosterone (FT) hormone had significantly increase in the BL + S and LP + S groups compared with control. Levels of LH and FSH hormones were the highest in the BL + S group. The treated groups showed all developmental stages of spermatogenesis, including spermatogenesis, spermatocytes, and seminiferous tubule spermatids, as well as intact Sertoli cells and Leydig cells without changes. When compared to the control group, sperm count and motility increased in the BL + S group, while sperm abnormalities decreased. The expression of Tspyl1 gene in testicular tissues decreased in the LP + S and BL + S groups, while the expression of Star and Hsd3b6 genes was higher in the BL + S group and lower in the LP + S group compared with the control group. Therefore, Bifidobacterium longum BSe50/20/1 enriched with selenium could be useful in enhancing male fertility.

Therapeutic modulation of the kynurenine pathway in severe mental illness and comorbidities: A potential role for serotonergic psychedelics

Mounting evidence points towards a crucial role of the kynurenine pathway (KP) in the altered gut-brain axis (GBA) balance in severe mental illness (SMI, namely depression, bipolar disorder, and schizophrenia) and cardiometabolic comorbidities. Preliminary evidence shows that serotonergic psychedelics and their analogues may hold therapeutic potential in addressing the altered KP in the dysregulated GBA in SMI and comorbidities. In fact, aside from their effects on mood, psychedelics elicit therapeutic improvement in preclinical models of obesity, metabolic syndrome, and vascular inflammation, which are highly comorbid with SMI. Here, we review the literature on the therapeutic modulation of the KP in the dysregulated GBA in SMI and comorbidities, and the potential application of psychedelics to address the altered KP in the brain and systemic dysfunction underlying SMI and comorbidities. Psychedelics might therapeutically modulate the KP in the altered GBA in SMI and comorbidities either directly, via altering the metabolic pathway by influencing the rate-limiting enzymes of the KP and affecting the levels of available tryptophan, or indirectly, by affecting the gut microbiome, gut metabolome, metabolism, and the immune system. Despite promising preliminary evidence, the mechanisms and outcomes of the KP modulation with psychedelics in SMI and systemic comorbidities remain largely unknown and require further investigation. Several concerns are discussed surrounding the potential side effects of this approach in specific cohorts of individuals with SMI and systemic comorbidities.

Altered gut microbiota and systemic immunity in Chinese patients with schizophrenia comorbid with metabolic syndrome

BACKGROUND

Metabolic syndrome (MetS) is highly prevalent in individuals with schizophrenia (SZ), leading to negative consequences like premature mortality. Gut dysbiosis, which refers to an imbalance of the microbiota, and chronic inflammation are associated with both SZ and MetS. However, the relationship between gut dysbiosis, host immunological dysfunction, and SZ comorbid with MetS (SZ-MetS) remains unclear. This study aims to explore alterations in gut microbiota and their correlation with immune dysfunction in SZ-MetS, offering new insights into its pathogenesis.

METHODS AND RESULTS

We enrolled 114 Chinese patients with SZ-MetS and 111 age-matched healthy controls from Zhejiang, China, to investigate fecal microbiota using Illumina MiSeq sequencing targeting 16 S rRNA gene V3-V4 hypervariable regions. Host immune responses were assessed using the Bio-Plex Pro Human Cytokine 27-Plex Assay to examine cytokine profiles. In SZ-MetS, we observed decreased bacterial α-diversity and significant differences in β-diversity. LEfSe analysis identified enriched acetate-producing genera (Megamonas and Lactobacillus), and decreased butyrate-producing bacteria (Subdoligranulum, and Faecalibacterium) in SZ-MetS. These altered genera correlated with body mass index, the severity of symptoms (as measured by the Scale for Assessment of Positive Symptoms and Scale for Assessment of Negative Symptoms), and triglyceride levels. Altered bacterial metabolic pathways related to lipopolysaccharide biosynthesis, lipid metabolism, and various amino acid metabolism were also found. Additionally, SZ-MetS exhibited immunological dysfunction with increased pro-inflammatory cytokines, which correlated with the differential genera.

CONCLUSION

These findings suggested that gut microbiota dysbiosis and immune dysfunction play a vital role in SZ-MetS development, highlighting potential therapeutic approaches targeting the gut microbiota. While these therapies show promise, further mechanistic studies are needed to fully understand their efficacy and safety before clinical implementation.

Investigating the Impacts of Diet, Supplementation, Microbiota, Gut-Brain Axis on Schizophrenia: A Narrative Review

Schizophrenia is a disease with a complex etiology that significantly impairs the functioning of patients. In recent years, there has been increasing focus on the importance of the gut microbiota in the context of the gut-brain axis. In our study, we analyzed data on the gut-brain axis in relation to schizophrenia, as well as the impacts of eating habits, the use of various supplements, and diets on schizophrenia. Additionally, the study investigated the impact of antipsychotics on the development of metabolic disorders, such as diabetes, dyslipidemia, and obesity. There may be significant clinical benefits to be gained from therapies supported by supplements such as omega-3 fatty acids, B vitamins, and probiotics. The results suggest the need for a holistic approach to the treatment of schizophrenia, incorporating both drug therapy and dietary interventions.

Nutrition and schizophrenia: associations worthy of continued revaluation

BACKGROUND

Accumulating evidence have shown that diet and nutrition play significant roles in mental illness, such as depression, anxiety and bipolar disorder. However, comprehensive evaluation of the relationship between nutrition and schizophrenia is lacking.

OBJECTIVE

The present review aims to synthetic elaborate the associations between nutrition and schizophrenia. Relevant studies on dietary patterns, macronutrients, micronutrients were performed through a literature search to synthesize the extracted data.

SUMMARY

Dietary interventions may help prevent the occurrence of schizophrenia, or delay symptoms: Healthy diets like nutritious plant-based foods and high-quality protein, have been linked to reducing the risk or symptoms of schizophrenia. Moreover, diet high in saturated fat and sugar is linked to more serious outcomes of schizophrenia. Additionally, when N-acetylcysteine acts as an adjuvant therapy, the overall symptoms of schizophrenia are significantly reduced. Also nascent evidence showed mental disorders may be related to intestinal microbiota dysfunction. Our study offered important insights into the dietary habits of patients with schizophrenia and the potential impact of nutritional factors on the disease. We also emphasized the need for further research, particularly in the form of large randomized double-blind controlled trials, to better understand the effects of nutrients on schizophrenia symptoms in different populations and disease types.

The relationship between the gut microbiota and oxidative stress in the cognitive function of schizophrenia: A pilot study in China

Cognitive impairment is a core symptom of schizophrenia. The gut microbiota (GM) and oxidative stress may play important roles in the pathophysiological mechanisms of cognitive impairment. This study aimed to explore the relationship between GM and oxidative stress in the cognitive function of schizophrenia. GM obtained by 16S RNA sequencing and serum superoxide dismutase (SOD) levels from schizophrenia patients (N = 68) and healthy controls (HCs, N = 72) were analyzed. All psychiatric symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS). Cognitive function was assessed using the MATRICS Consensus Cognitive Battery (MCCB). Correlation analysis was used to explore the relationship between GM, SOD, and cognitive function. Machine learning models were used to identify potential biomarkers. Compared to HCs, the relative abundances of Collinsella, undefined Ruminococcus, Lactobacillus, Eubacterium, Mogibacterium, Desulfovibrio, Bulleidia, Succinivibrio, Corynebacterium, and Atopobium were higher in patients with schizophrenia, but Faecalibacterium, Anaerostipes, Turicibacter, and Ruminococcus were lower. In patients with schizophrenia, the positive factor, general factor, and total score of MCCB positively correlated with Lactobacillus, Collinsella, and Lactobacillus, respectively; SOD negatively correlated with Eubacterium, Collinsella, Lactobacillus, Corynebacterium, Bulleidia, Mogibacterium, and Succinivibrio, but positively correlated with Faecalibacterium, Ruminococcus, and MCCB verbal learning index scores; Faecalibacterium and Turicibacter were positively correlated with MCCB visual learning index scores and speed of processing index scores, respectively. Our findings revealed a correlation between SOD and GM and confirmed that cognitive dysfunction in patients with schizophrenia involves abnormal SOD levels and GM changes.

Effectiveness of Psychobiotics in the Treatment of Psychiatric and Cognitive Disorders: A Systematic Review of Randomized Clinical Trials

In this study, a systematic review of randomized clinical trials conducted from January 2000 to December 2023 was performed to examine the efficacy of psychobiotics-probiotics beneficial to mental health via the gut-brain axis-in adults with psychiatric and cognitive disorders. Out of the 51 studies involving 3353 patients where half received psychobiotics, there was a notably high measurement of effectiveness specifically in the treatment of depression symptoms. Most participants were older and female, with treatments commonly utilizing strains of Lactobacillus and Bifidobacteria over periods ranging from 4 to 24 weeks. Although there was a general agreement on the effectiveness of psychobiotics, the variability in treatment approaches and clinical presentations limits the comparability and generalization of the findings. This underscores the need for more personalized treatment optimization and a deeper investigation into the mechanisms through which psychobiotics act. The research corroborates the therapeutic potential of psychobiotics and represents progress in the management of psychiatric and cognitive disorders.

Nutraceuticals in Psychiatric Disorders: A Systematic Review

Correct nutrition and diet are directly correlated with mental health, functions of the immune system, and gut microbiota composition. Diets with a high content of some nutrients, such as fibers, phytochemicals, and short-chain fatty acids (omega-3 fatty acids), seem to have an anti-inflammatory and protective action on the nervous system. Among nutraceuticals, supplementation of probiotics and omega-3 fatty acids plays a role in improving symptoms of several mental disorders. In this review, we collect data on the efficacy of nutraceuticals in patients with schizophrenia, autism spectrum disorders, major depression, bipolar disorder, and personality disorders. This narrative review aims to provide an overview of recent evidence obtained on this topic, pointing out the direction for future research.

Probiotic, prebiotic, synbiotic and fermented food supplementation in psychiatric disorders: A systematic review of clinical trials

The use of probiotics, prebiotics, synbiotics or fermented foods can modulate the gut-brain axis and constitute a potentially therapeutic intervention in psychiatric disorders. This systematic review aims to identify current evidence regarding these interventions in the treatment of patients with DSM/ICD psychiatric diagnoses. Forty-seven articles from 42 studies met the inclusion criteria. Risk of bias was assessed in all included studies. Major depression was the most studied disorder (n = 19 studies). Studies frequently focused on schizophrenia (n = 11) and bipolar disorder (n = 5) and there were limited studies in anorexia nervosa (n = 4), ADHD (n = 3), Tourette (n = 1), insomnia (n = 1), PTSD (n = 1) and generalized anxiety disorder (n = 1). Except in MDD, current evidence does not clarify the role of probiotics and prebiotics in the treatment of mental illness. Several studies point to an improvement in the immune and inflammatory profile (e.g. CRP, IL6), which may be a relevant mechanism of action of the therapeutic response identified in these studies. Future research should consider lifestyle and dietary habits of patients as possible confounders that may influence inter-individual treatment response.

Are probiotics effective in reducing the metabolic side effects of psychiatric medication? A scoping review of evidence from clinical studies

The psychopharmacological treatment of patients with schizophrenia or depression is often accompanied by serious side effects. In particular, the clinical findings of weight gain are worrying, as this side effect can lead to various medical sequelae in the future. However, the treatment of metabolic changes in psychiatric patients is often neglected or unsuccessful. An improved knowledge of possible therapeutic approaches is needed. The aim of this study was to provide an overview of the utilisation and effectiveness of probiotics in reducing weight gain in patients with severe mental illness. A scoping review of studies published until 15 June 2022 was conducted to identify studies using probiotics in people with schizophrenia or depression. We systematically searched the databases EMBASE, PubMed (MEDLINE), Web of Science and SCOPUS with a predefined search string. In addition, reference lists of relevant publications were examined for additional studies. The studies were assessed by two reviewers. The primary outcomes were weight-related measurements. The secondary outcomes were metabolic blood parameters and gut microbiota. Four studies ultimately met the inclusion criteria. Two studies in which probiotics were administered did not find significant effects on pharmacologically induced weight gain. The other two studies examined the effects of synbiotics (a combination of probiotics and prebiotics). Interestingly, less weight gain was observed in individuals with this combined intervention. Adjustments in diet can be helpful and are generally well-accepted interventions in the fight against pharmacologically induced weight gain. The clinical use of probiotics and prebiotics (or synbiotics) as dietary interventions may represent a promising additional strategy in this regard. However, the few studies available showed no clear conclusions.

Nutraceuticals and phytoceuticals in the treatment of schizophrenia: a systematic review and network meta-analysis

Background

Sub-optimal response in schizophrenia is frequent, warranting augmentation strategies over treatment-as-usual (TAU).

Methods

We assessed nutraceuticals/phytoceutical augmentation strategies via network meta-analysis. Randomized controlled trials in schizophrenia/schizoaffective disorder were identified via the following databases: PubMed, MEDLINE, EMBASE, Scopus, PsycINFO, CENTRAL, and ClinicalTrials.gov. Change (Standardized Mean Difference=SMD) in total symptomatology and acceptability (Risk Ratio=RR) were co-primary outcomes. Secondary outcomes were positive, negative, cognitive, and depressive symptom changes, general psychopathology, tolerability, and response rates. We conducted subset analyses by disease phase and sensitivity analyses by risk of bias and assessed global/local inconsistency, publication bias, risk of bias, and confidence in the evidence.

Results

The systematic review included 49 records documenting 50 studies (n=2,384) documenting 22 interventions. Citicoline (SMD=-1.05,95%CI=-1.85; -.24), L-lysine (SMD=-1.04,95%CI=-1.84;-.25), N-acetylcysteine (SMD=-.87,95%CI=-1.27;-.47) and sarcosine (SMD=-.5,95%CI=-.87-.13) outperformed placebo for total symptomatology. High heterogeneity (tau2=.10, I2=55.9%) and global inconsistency (Q=40.79, df=18, p=.002) emerged without publication bias (Egger's test, p=.42). Sarcosine improved negative symptoms (SMD=-.65, 95%CI=-1.10; -.19). N-acetylcysteine improved negative symptoms (SMD=-.90, 95%CI=-1.42; -.39)/general psychopathology (SMD=-.76, 95%CI=-1.39; -.13). No compound improved total symptomatology within acute phase studies (k=7, n=422). Sarcosine (SMD=-1.26,95%CI=-1.91; -.60), citicoline (SMD=-1.05,95%CI=-1.65;-.44), and N-acetylcysteine (SMD=-.55,95%CI=-.92,-.19) outperformed placebo augmentation in clinically stable participants. Sensitivity analyses removing high-risk-of-bias studies confirmed overall findings in all phases and clinically stable samples. In contrast, the acute phase analysis restricted to low risk-of-bias studies showed a superior effect vs. placebo for N-acetylcysteine (SMD=-1.10,95%CI=-1.75,-.45), L-lysine (SMD=-1.05,95%CI=-1.55,-.19), omega-3 fatty acids (SMD=-.83,95%CI=-1.31,-.34) and withania somnifera (SMD=-.71,95%CI=-1.21,-.22). Citicoline (SMD=-1.05,95%CI=-1.86,-.23), L-lysine (SMD=-1.04,95%CI=-1.84,-.24), N-acetylcysteine (SMD=-.89,95%CI=-1.35,-.43) and sarcosine (SMD=-.61,95%CI=-1.02,-.21) outperformed placebo augmentation of TAU ("any phase"). Drop-out due to any cause or adverse events did not differ between nutraceutical/phytoceutical vs. placebo+TAU.

Conclusions

Sarcosine, citicoline, and N-acetylcysteine are promising augmentation interventions in stable patients with schizophrenia, yet the quality of evidence is low to very low. Further high-quality trials in acute phases/specific outcomes/difficult-to-treat schizophrenia are warranted.

Evaluating the association of vitamin D3, parathyroid hormone, and C-reactive protein serum levels in patients with an acute psychotic episode: a cross-sectional study in tertiary centre in Iran

BACKGROUND

The high impact of vitamin D on brain development and its relationship with inflammatory markers in the clinical course of psychiatric disorders have compelled researchers to investigate the potential association between vitamin D levels, C-reactive protein (CRP) levels, and the incidence of mental disorders. In the present study, we aimed to compare the serum levels of vitamin D and its related markers, including calcium, phosphorus, and parathyroid hormone (PTH), along with CRP, in 3 groups of patients with acute psychotic episodes, including schizophrenia, bipolar disorder, and methamphetamine-induced psychosis, with a standard control group of the Iranian population.

METHODS

This descriptive cross-sectional study was conducted at a psychiatric hospital in Tehran, Iran, and involved a total of 185 subjects. The subjects included four groups: acute phase of schizophrenia (n = 49), acute manic episodes of bipolar disorder (n = 43), methamphetamine-induced psychotic disorder (n = 46), and control group (n = 47). Among 138 patients in acute psychotic episodes, 33 patients were in their first episode of psychosis, while 105 patients were in acute exacerbation of their chronic psychotic disorders. The Brief Psychiatric Rating Scale (BPRS) was measured by an expert attending psychiatrist for all patients. Then, serum levels of calcium, phosphorus, parathormone, vitamin D, and CRP were assessed in all study groups.

RESULTS

Among our 185 study subjects, it was observed that individuals with higher education levels and those who were married had a lower prevalence of mental disorders. In all patient groups, the serum levels of CRP were significantly higher, and PTH levels were significantly lower than in the control group (p < 0.001). The serum levels of calcium, phosphorus, and vitamin D were not statistically significantly different between the patient and control groups of the study. In chronic psychotic patients, CRP levels were significantly higher (p < 0.031), and vitamin D levels were significantly lower (p < 0.044) compared to first-episode psychotic patients.

CONCLUSION

This study suggests that CRP levels are significantly higher and PHT level is significantly lower in acute psychotic patients. Moreover, vitamin D levels were significantly lower in chronic psychotic patients compared to first-episode psychotic patients.

The synergistic effect of Levilactobacillus brevis IBRC-M10790 and vitamin D3 on Helicobacter pylori-induced inflammation

Background

Owing to the emergence and spread of multidrug resistance mechanisms in Helicobacter pylori, achieving a successful eradication has become exceedingly difficult. Thus, this study for the first time determines the effect of a combination of vitamin D3 and probiotic on the pathogenesis and treatment of H. pylori.

Methods

We established an in vitro experimental system using AGS human gastric carcinoma cells and explored the synergistic effect of Levilactobacillus brevis IBRC-M10790 and vitamin D3 on H. pylori. Live and pasteurized L. brevis, L. brevis-derived membrane vesicles (MVs), and L. brevis cell-free supernatant (CFS), as well as their combination with vitamin D3 were used during this study. We assessed the anti-inflammatory and anti-oxidative effects of these combinations using RT-qPCR and ELISA, respectively. We further performed an adhesion assay to evaluate the influence of L. brevis and vitamin D3 on the adherence rate of H. pylori to AGS cells.

Results

Our results demonstrated that L. brevis and vitamin D3 possess anti-inflammatory and anti-oxidative effects against H. pylori infection in AGS cells. The combination of vitamin D3 with the probiotic strain (particularly live L. brevis and its CFS) can more efficiently reduce the expression of pro-inflammatory cytokines IL-6, IL-8, IFN-γ, and TNF-α in the AGS cells. Moreover, vitamin D3 and L. brevis exhibited an additive impact preserving the integrity of the epithelial barrier by increasing the expression of the tight junction protein ZO-1. Furthermore, this combination can potentially reduce H. pylori adherence to AGS cells.

Conclusions

This study indicates the advantage of combining vitamin D3 and probiotic to attenuate H. pylori-induced inflammation and oxidative stress. Consequently, probiotic and vitamin D3 co-supplementation can be considered as a novel therapeutic approach to manage and prevent H. pylori infection.

Effects of Probiotic and Selenium Co-supplementation on Lipid Profile and Glycemia Indices: A Systematic Review and Meta-analysis of Randomized Clinical Trials

PURPOSE OF REVIEW

The current systematic review and meta-analysis was done to evaluate the effects of selenium and probiotic co-supplementation on lipid profile and glycemia indices of the adult population using randomized controlled clinical trials (RCTs).

RECENT FINDINGS

Five studies involving 282 participants with a sample size ranging from 38 to 79 were eligible to be enrolled in the current study. Co-supplementation with probiotic and selenium reduced fasting plasma glucose (WMD =  -4.02 mg/dL; 95% CI: -5.87 to -2.18; P < 0.001), insulin (WMD =  -2.50 mIU/mL; 95% CI: -3.11 to -1.90; P < 0.001), homeostatic model assessment for insulin resistance (WMD =  -0.59; 95% CI: -0.74 to -0.43; P < 0.001), quantitative insulin sensitivity check index (WMD = 0.01; 95% CI: 0.01 to 0.02; P < 0.001), total cholesterol (WMD =  -12.75 mg/dL; 95% CI: -19.44 to -6.07; P < 0.001), low-density lipoprotein cholesterol (WMD =  -7.09 mg/dL; 95% CI: -13.45 to -0.73; P = 0.029), and triglyceride (WMD =  -14.38 mg/dL; 95% CI: -23.13 to -5.62; P = 0.001). The findings of the current systematic review and meta-analysis suggested that co-supplementation with probiotics and selenium may benefit adults in terms of glycemia indices and lipid profile. However, due to the small number of included studies, further trials are needed to confirm our findings.

Clinical significance of microbiota changes under the influence of psychotropic drugs. An updated narrative review

Relationship between drugs and microbiota is bilateral. Proper composition thus function of microbiota is a key to some medications used in modern medicine. However, there is also the other side of the coin. Pharmacotherapeutic agents can modify the microbiota significantly, which consequently affects its function. A recently published study showed that nearly 25% of drugs administered to humans have antimicrobial effects. Multiple antidepressants are antimicrobials,. and antibiotics with proven antidepressant effects do exist. On the other hand, antibiotics (e.g., isoniaside, minocycline) confer mental phenotype changes, and adverse effects caused by some antibiotics include neurological and psychological symptoms which further supports the hypothesis that intestinal microbiota may affect the function of the central nervous system. Here we gathered comprehensively data on drugs used in psychiatry regarding their antimicrobial properties. We believe our data has strong implications for the treatment of psychiatric entities. Nevertheless the study of ours highlights the need for more well-designed trials aimed at analysis of gut microbiota function.

Reviewing the Potential Therapeutic Approaches Targeting the Modulation of Gastrointestinal Microflora in Schizophrenia

Schizophrenia (SCZ) is a severe brain disorder characterized by an intriguing clinical panel that has begun to gain interest due to its particular phenotype. Having considered the role of gut microflora in psychiatry, the latest discoveries might offer further insight into the underlying mechanisms. Thus, we aimed to offer an updated overview of the therapeutic potential of microorganism-derived supplements alongside dedicated protocols that target the re-establishment of the host's eubiosis. Based on combinations of specific keywords, we performed searches in four databases (PubMed/Medline, ISI Web of Knowledge, Scopus, and ScienceDirect) for the established interval (2018-2022) and identified twenty two eligible cases, restricted only to human patients' experiences. Up until the writing of this manuscript, it has been revealed that the administration of specific lactic acid bacteria strains (Lactobacillus and Bifidobacterium), or those combined with vitamin D and selenium, maintain the integrity of the gut flora, preventing antagonistic effects including inflammation, antipsychotic-related body weight gain (olanzapine) and other metabolic dysfunctionalities. However, there are multiple antipsychotics that exert a potent effect upon gut flora, influencing a plethora of pathways and creating a dysbalance ratio between beneficial and opportunistic pathogens. Risperidone, amisulpride, and clozapine are just a few examples, but the current literature is unfortunately inconsistent and reported data is contradictory, which is why we support additional studies in this context. Moreover, we further argue the utility of studying how distinct controlled substances influence microbial communities, considering that ketamine is proved to alleviate depressive-like behavior as opposed to amphetamine and phencyclidine, which are known substances to trigger SCZ-like symptoms in experimental models. Probiotics may be regarded as the most consequential vehicle through which the gut flora can be successfully influenced, in adequate doses exerting a beneficial role as an alternative approach to alleviate SCZ symptoms.

Genetic association between circulating selenium level and the risk of schizophrenia in the European population: A two-sample Mendelian randomization study

Background

The association between circulating the selenium level and the risk of schizophrenia remains unclear.

Objective

To determine the relationship between the circulating selenium level and the risk of schizophrenia, using the Mendelian Randomization method in the European population.

Methods

Single nucleotide polymorphisms (SNPs) associated with the circulating selenium level were identified at p < 5 × 10⁻⁸. The inverse variance weighted (IVW) method was used as the principal MR analysis, and MR Egger, weighted median, and MR PRESSO were used to determine the accuracy of IVW results. The Cochran's Q-test and Leave-One-Out sensitivity analysis were performed to evaluate the heterogeneity and stability of genetic variants on schizophrenia.

Results

The circulating selenium level was associated with decreased risk of schizophrenia by the IVW method (OR: 0.906, 95% CI:0.867–0.947). MR Egger, weighted median, and MR PRESSO methods got similar results. No heterogeneity was detected by the Cochran's Q-test, and no single SNP was driving the overall effect by leave-one-out analysis.

Conclusion

Our study provides support for the genetic relationship between the circulating selenium level and schizophrenia; the decreased circulating selenium level was associated with an elevated risk of schizophrenia.

Gut microbiome in schizophrenia and antipsychotic-induced metabolic alterations: a scoping review

Schizophrenia (SCZ) is a severe mental disorder with high morbidity and lifetime disability rates. Patients with SCZ have a higher risk of developing metabolic comorbidities such as obesity and diabetes mellitus, leading to increased mortality. Antipsychotics (APs), which are the mainstay in the treatment of SCZ, increase the risk of these metabolic perturbations. Despite extensive research, the mechanism underlying SCZ pathophysiology and associated metabolic comorbidities remains unclear. In recent years, gut microbiota (GMB) has been regarded as a 'chamber of secrets', particularly in the context of severe mental illnesses such as SCZ, depression, and bipolar disorder. In this scoping review, we aimed to investigate the underlying role of GMB in the pathophysiology of SCZ and metabolic alterations associated with APs. Furthermore, we also explored the therapeutic benefits of prebiotic and probiotic formulations in managing SCZ and AP-induced metabolic alterations. A systematic literature search yielded 46 studies from both preclinical and clinical settings that met inclusion criteria for qualitative synthesis. Preliminary evidence from preclinical and clinical studies indicates that GMB composition changes are associated with SCZ pathogenesis and AP-induced metabolic perturbations. Fecal microbiota transplantation from SCZ patients to mice has been shown to induce SCZ-like behavioral phenotypes, further supporting the plausible role of GMB in SCZ pathogenesis. This scoping review recapitulates the preclinical and clinical evidence suggesting the role of GMB in SCZ symptomatology and metabolic adverse effects associated with APs. Moreover, this scoping review also discusses the therapeutic potentials of prebiotic/probiotic formulations in improving SCZ symptoms and attenuating metabolic alterations related to APs.

Role of the gut microbiome in three major psychiatric disorders

Major depressive disorder (MDD), bipolar disorder (BD) and schizophrenia-spectrum disorders (SSD) are heterogeneous psychiatric disorders, which place significant burden on patient's well-being and global health. Disruptions in the gut-microbiome may play a role in these psychiatric disorders. This review presents current data on composition of the human gastrointestinal microbiota, and its interaction mechanisms in the gut-brain axis in MDD, BD and SSD. Diversity metrics and microbial relative abundance differed across studies. More studies reported inconsistent findings (n = 7) or no differences (n = 8) than studies who reported lower α-diversity in these psychiatric disorders (n = 5). The most consistent findings across studies were higher relative abundances of the genera Streptococcus, Lactobacillus, and Eggerthella and lower relative abundance of the butyrate producing Faecalibacterium in patients with psychiatric disorders. All three increased genera were associated with higher symptom severity. Confounders, such as medication use and life style have not been accounted for. So far, the results of probiotics trials have been inconsistent. Most traditional and widely used probiotics (consisting of Bifidobacterium spp. and Lactobacillus spp.) are safe, however, they do not correct potential microbiota disbalances in these disorders. Findings on prebiotics and faecal microbiota transplantation (FMT) are too limited to draw definitive conclusions. Disease-specific pro/prebiotic treatment or even FMT could be auspicious interventions for prevention and therapy for psychiatric disorders and should be investigated in future trials.

The microbiome, guard or threat to infant health

Despite improvements in survival for very low birthweight (VLBW) premature infants, there continues to be significant morbidity for these infants at remarkable cost to the healthcare system. Concurrent development of the preterm infant intestine alongside the gut microbiome in the clinical setting rather than in the protected in utero environment where it would usually occur creates significant vulnerabilities for the infant's immature intestine and immune system, resulting in devastating illness and neurological injury. However, the microbiome also has the capacity to promote healthy development. Studies of parallel gut microbiome and preterm infant development have given key insight into the impact of the microbiome on intestinal as well as neural development and may provide potential therapeutic targets to prevent preterm infant morbidities.