Infection and inflammation in schizophrenia and bipolar disorder

Physical multimorbidity is not independently associated with cognitive performance in patients with older-age bipolar disorder (OABD)

OBJECTIVES

Cognitive impairment is common in bipolar disorder (BD), especially in older age (≥50 years). Underlying causes of BD-related cognitive impairment are not fully elucidated. This study investigates the association between physical multimorbidity and subjective and objective cognitive performance in patients with older age bipolar disorder (OABD).

DESIGN

Cross-sectional design.

SETTING

Dutch Older Bipolars (DOBi) dynamic cohort.

PARTICIPANTS

170 outpatients with BD aged ≥ 50 years.

MEASUREMENTS

Chronic physical diseases were assessed in a structured interview. Objective cognitive performance was measured with neuropsychological tests, subjective cognitive performance with the Cognitive Failures Questionnaire (CFQ). Linear regression analyses were performed between multimorbidity, defined as two or more affected physical disease domains, and 1) objective cognitive performance, 2) subjective cognitive functioning, and 3) four cognitive domain scores (attention, learning and memory, verbal fluency, executive functioning). Analyses were hierarchically adjusted for demographic, lifestyle, and psychiatric characteristics.

RESULTS

Multimorbidity was significantly associated with a lower composite cognitive score (B=-0.205, p = 0.040), but after full adjustment statistical significance disappeared (B=-0.044, p = 0.633). Controlled for demographics only, multimorbidity was not significantly associated with higher CFQ (B=6.009, p = 0.053). Multimorbidity was associated with worse executive functioning (B=-0.279, p = 0.018), but statistical significance disappeared after full adjustment (B=-0.085, p = 0.469).

CONCLUSIONS

In OABD physical multimorbidity is not independently associated with poorer cognitive performance and subjective functioning. Rather, shared risk factors, such as demographics, psychiatric characteristics, and lifestyle factors might lead to both the presence of physical diseases and worse cognitive performance in OABD.

Increased Herpes simplex virus 1, Toxoplasma gondii and Cytomegalovirus antibody concentrations in severe mental illness

Infections with Cytomegalovirus (CMV), Herpes simplex virus 1 (HSV1) and Toxoplasma gondii (TG) have been implicated in severe mental illness. All three pathogens have high seroprevalence in the human population, are neurotropic and establish a persistent infection. We hypothesized that exposed (seropositive) patients with severe mental illness would show higher immunoglobulin G (IgG) concentrations than exposed healthy controls (HC). We included 765 patients with severe mental illness (schizophrenia n = 515, bipolar disorder n = 250) and 541 HC. CMV, HSV1 and TG IgG seropositivity and concentrations were measured with immunoassays (seropositivity: CMV, n = 447 patients vs. 296 HC; HSV1, n = 355 vs. 238; and TG, n = 159 vs. 126). Among seropositive participants, patients had higher HSV1 (p < 0.001) and TG (p = 0.003) IgG concentrations than HC. Stratifying by diagnosis, both schizophrenia (p = 0.001) and bipolar disorder (p = 0.001) had higher HSV1 IgG concentrations, while schizophrenia only had higher TG (p = 0.009) and CMV (p = 0.045) IgG concentrations than HC. In SZ, higher HSV1 IgG concentrations were associated with higher psychotic (p = 0.030) and manic (p = 0.008) symptom scores, but only among CMV- or TG-infected patients which suggests synergistic effects. Among all participants, HSV1 IgG concentrations were inversely associated with interleukin-18 (p < 0.001) and positively associated with high-sensitivity C-reactive protein (p = 0.002) and B cell-activating factor (p = 0.004), possibly indicating T cell exhaustion, enhanced inflammation, and increased B-cell response, respectively. Patients with severe mental illness exhibit a heightened immune system response to HSV1, TG, and CMV infections suggesting immune system dysfunction and/or a more severe infection. For HSV1, higher IgG concentrations were linked to a greater clinical burden.

Nuclear GAPDH in cortical microglia mediates cellular stress-induced cognitive inflexibility

We report a mechanism that underlies stress-induced cognitive inflexibility at the molecular level. In a mouse model under subacute cellular stress in which deficits in rule shifting tasks were elicited, the nuclear glyceraldehyde dehydrogenase (N-GAPDH) cascade was activated specifically in microglia in the prelimbic cortex. The cognitive deficits were normalized with a pharmacological intervention with a compound (the RR compound) that selectively blocked the initiation of N-GAPDH cascade without affecting glycolytic activity. The normalization was also observed with a microglia-specific genetic intervention targeting the N-GAPDH cascade. At the mechanistic levels, the microglial secretion of High-Mobility Group Box (HMGB), which is known to bind with and regulate the NMDA-type glutamate receptors, was elevated. Consequently, the hyperactivation of the prelimbic layer 5 excitatory neurons, a neural substrate for cognitive inflexibility, was also observed. The upregulation of the microglial HMGB signaling and neuronal hyperactivation were normalized by the pharmacological and microglia-specific genetic interventions. Taken together, we show a pivotal role of cortical microglia and microglia-neuron interaction in stress-induced cognitive inflexibility. We underscore the N-GAPDH cascade in microglia, which causally mediates stress-induced cognitive alteration.

Toxoplasma gondii IgG serointensity and cognitive function in bipolar disorder

BACKGROUND

Alongside affective episodes, cognitive dysfunction is a core symptom of bipolar disorder. The intracellular parasite T. gondii has been positively associated with both, the diagnosis of bipolar disorder and poorer cognitive performance, across diagnostic boundaries. This study aims to investigate the association between T. gondii seropositivity, serointensity, and cognitive function in an euthymic sample of bipolar disorder.

METHODS

A total of 76 participants with bipolar disorder in remission were tested for T. gondii-specific IgG and IgM antibodies and for cognitive performance using neuropsychological test battery. Cognitive parameters were categorized into three cognitive domains (attention and processing speed, verbal memory, and executive function). Statistical analysis of associations between continuous indicators of cognitive function as dependent variables in relationship to T. gondii, included multivariate analyses of co-variance for seropositivity, and partial correlations with IgG serointensity in IgG seropositives. All analyses were controlled for age and premorbid IQ.

RESULTS

In seropositives (n = 27), verbal memory showed significant inverse partial correlations with IgG antibody levels (short delay free recall (r=-0.539, p = 0.005), long delay free recall (r=-0.423, p = 0.035), and immediate recall sum trial 1-5 (r=-0.399, p = 0.048)). Cognitive function did not differ between IgG seropositive and seronegative individuals in any of the cognitive domains (F (3,70) = 0.327, p = 0.806, n = 76). IgM positives (n = 7) were too few to be analyzed.

CONCLUSIONS

This investigation is the first to show an association between T. gondii IgG serointensity and memory function in a well-diagnosed bipolar disorder sample. It adds to the existing literature on associations between latent T. gondii infection and cognition in bipolar disorder, while further research is needed to confirm and expand our findings, eliminate potential sources of bias, and establish cause-effect relationships.

Comparison of Extracellular Vesicles from Induced Pluripotent Stem Cell-Derived Brain Cells

The pathophysiology of many neuropsychiatric disorders is still poorly understood. Identification of biomarkers for these diseases could benefit patients due to better classification and stratification. Exosomes excreted into the circulatory system can cross the blood-brain barrier and carry a cell type-specific set of molecules. Thus, exosomes are a source of potential biomarkers for many diseases, including neuropsychiatric disorders. Here, we investigated exosomal proteins produced from human-induced pluripotent stem cells (iPSCs) and iPSC-derived neural stem cells, neural progenitors, neurons, astrocytes, microglia-like cells, and brain capillary endothelial cells. Of the 31 exosome surface markers analyzed, a subset of biomarkers were significantly enriched in astrocytes (CD29, CD44, and CD49e), microglia-like cells (CD44), and neural stem cells (SSEA4). To identify molecular fingerprints associated with disease, circulating exosomes derived from healthy control (HC) individuals were compared against schizophrenia (SCZ) patients and late-onset Alzheimer's disease (LOAD) patients. A significant epitope pattern was identified for LOAD (CD1c and CD2) but not for SCZ compared to HC. Thus, analysis of cell type- and disease-specific exosome signatures of iPSC-derived cell cultures may provide a valuable model system to explore proteomic biomarkers for the identification of novel disease profiles.

From gut to brain: A network model of intestinal permeability, inflammation, and psychotic symptoms in schizophrenia

Impaired intestinal permeability has recently been suggested as a possible source of chronic inflammation in schizophrenia, but its association with specific psychopathological features remains uncertain. This study aimed to explore the interaction between intestinal permeability, inflammation, and positive and negative symptoms in schizophrenia using a network analysis approach. The study sample comprised 281 adults with schizophrenia (age 40.29 ± 13.65 years, 63.0 % males), enrolled in a cross-sectional observational study assessing intestinal permeability. We estimated the network with a Gaussian graphical model, incorporating scores from 14 individual items of the Positive and Negative Syndrome Scale (PANSS), along with body mass index (BMI), and plasma C-reactive protein (CRP) and lipopolysaccharide-binding protein (LBP) levels. We calculated strength centrality and expected influence and used bridge centrality statistics to identify the bridge nodes. Distinct but highly interconnected clusters emerged for positive and negative symptoms. The biological variables were closely associated with each other. LBP was positively linked with CRP and BMI, but only indirectly connected to psychopathology. CRP exhibited direct positive relationships with various PANSS items and bridged LBP and BMI with psychopathology. Bridge nodes included Conceptual Disorganisation (P2), Active Social Avoidance (G16), Suspiciousness/Persecution (P6), and CRP. These findings support the role of gut-derived inflammation as a mechanism underlying greater symptom severity in schizophrenia and emphasise the importance of addressing dietary habits not only to enhance physical health but also to contribute to improving psychotic symptoms.

Association of common infections with cognitive performance in the Baltimore Epidemiologic Catchment Area study follow-up

INTRODUCTION

Growing evidence suggests that some common infections are causally associated with cognitive impairment; however, less is known about the burden of multiple infections.

METHODS

We investigated the cross-sectional association of positive antibody tests for herpes simplex virus, cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella zoster virus (VZV), and Toxoplasma gondii (TOX) with Mini-Mental State Examination (MMSE) and delayed verbal recall performance in 575 adults aged 41-97 from the Baltimore Epidemiologic Catchment Area Study.

RESULTS

In multivariable-adjusted zero-inflated Poisson (ZIP) regression models, positive antibody tests for CMV (p = .011) and herpes simplex virus (p = .018) were individually associated with poorer MMSE performance (p = .011). A greater number of positive antibody tests among the five tested was associated with worse MMSE performance (p = .001).

DISCUSSION

CMV, herpes simplex virus, and the global burden of multiple common infections were independently associated with poorer cognitive performance. Additional research that investigates whether the global burden of infection predicts cognitive decline and Alzheimer's disease biomarker changes is needed to confirm these findings.

Changes in Inflammatory Biomarkers in Patients with Schizophrenia: A 3-Year Retrospective Study

Objective

Accumulating evidence suggested that immune system activation might be involved in the pathophysiology of schizophrenia. The neutrophil/lymphocyte ratio (NLR), monocyte/lymphocyte ratio (MLR), platelet/lymphocyte ratio (PLR) and systemic immune-inflammation index (SII) can measure inflammation. This study aimed to investigate the inflammatory state in patients with schizophrenia by using these indicators.

Methods

In this study, the complete blood count data for 187 continuing hospitalized patients with schizophrenia and 187 age- and sex-matched healthy participants was collected annually from 2017 to 2019. Platelet (PLT), lymphocyte (LYM), monocyte (MON) and neutrophil (NEU) counts were aggregated and NLR, MLR, PLR, and SII were calculated. Using a generalized linear mixed model, we assessed the impact of age, sex, diagnosis, and sampling year on the above indicators and evaluated the interaction between the factors.

Results

According to the estimation results of the generalized linear mixed model, the NLR increased by 0.319 (p = 0.004), the MLR increased by 0.037 (p < 0.001), and the SII increased by 57.858 (p = 0.018) in patients with schizophrenia. Data after two years of continuous antipsychotic treatment showed that the NLR and MLR were higher in patients with schizophrenia than those in healthy controls, while the PLT and LYM counts were decreased in patients with schizophrenia. The schizophrenia diagnosis was correlated to the MON and LYM count, NLR, MLR, and SII (p < 0.05).

Conclusion

The differences in these markers were stable and cannot be eliminated by a full course of treatment. This study provides impetus for the inflammatory hypothesis of schizophrenia.

Acute Onset of Mania and Psychosis in the Context of Long-COVID: A Case Study

Acute phase COVID-19 has been associated with an increased risk for several mental health conditions, but less is known about the interaction of long COVID and mental illness. Prior reports have linked long COVID to PTSD, depression, anxiety, obsessive compulsive symptoms, and insomnia. This case report describes a novel presentation of mania arising in the context of long COVID symptoms with attention given to possible interacting etiological pathways. The case report also highlights the need for integrated, multidisciplinary treatment to support patients whose alarming, confusing, and multidetermined symptoms increase risk of psychological deterioration.

Construction of a Diagnostic Model and a lncRNA-Associated ceRNA Network Based on Apoptosis-Related Genes for Schizophrenia

Methods

Gene expression profiles and apoptosis-related data were downloaded from the Gene Expression Omnibus and Molecular Signature databases, respectively. Apoptosis-related differentially expressed mRNAs (DEGs) and miRNAs (DEMs) from blood samples between the schizophrenia and healthy control individuals were screened. A diagnostic model was developed using the data from univariate and least absolute shrinkage and selection operator (LASSO) regression analyses, followed by validation using the GSE38485 dataset. Cases were divided into low-risk (LR) and high-risk (HR) groups based on the risk score of the model, and differences in immune gene sets and pathways between these two groups were compared. Finally, a ceRNA network was constructed by integrating long non-coding RNAs (lncRNAs), DEMs, and DEGs.

Results

A diagnostic model containing 15 apoptosis-related genes was developed and its diagnostic efficiency was found to be robust. The HR group was correlated with higher immune scores of chemokines, cytokines, and interleukins; it was also significantly involved in pathways such as pancreatic beta cells and early estrogen response. A ceRNA network composed of 2 lncRNAs, 14 miRNAs, and 5 mRNAs was established.

Conclusions

The established model is a potential tool to improve the diagnostic efficiency of patients with schizophrenia, and the nodes included in the ceRNA network might serve as biomarkers and therapeutic targets for schizophrenia.

Association between gut permeability, brain volume, and cognition in healthy participants and patients with schizophrenia spectrum disorder

INTRODUCTION

The barrier function of the gut is important for many organs and systems, including the brain. If gut permeability increases, bacterial fragments may enter the circulation, giving rise to increased systemic inflammation. Increases in bacterial translocation are reflected in higher values of blood markers, including lipopolysaccharide binding protein (LBP) and soluble cluster of differentiation 14 (sCD14). Some pioneer studies showed a negative association between bacterial translocation markers and brain volumes, but this association remains scarcely investigated. We investigate the effect of bacterial translocation on brain volumes and cognition in both healthy controls and patients with a schizophrenia spectrum disorder (SSD).

MATERIALS AND METHODS

Healthy controls (n = 39) and SSD patients (n = 72) underwent an MRI-scan, venipuncture and cognition assessments. We investigated associations between LBP and sCD14 and brain volumes (intracranial volume, total brain volume, and hippocampal volume) using linear regression. We then associated LBP and sCD14 to cognitive function using a mediation analysis, with intracranial volume as mediator.

RESULTS

Healthy controls showed a negative association between hippocampal volume and LBP (b = -0.11, p = .04), and intracranial volume and sCD14 (b = -0.25, p = .07). Both markers were indirectly associated with lower cognitive functioning in healthy controls (LBP: b = -0.071, p = .028; sCD14: b = -0.213, p = .052), mediated by low intracranial volume. In the SSD patients, these associations were markedly less present.

CONCLUSION

These findings extend earlier studies suggesting that increased bacterial translocation may negatively affect brain volume, which indirectly impacts cognition, even in this young healthy group. If replicated, this finding stresses the importance of a healthy gut for the development and optimal functioning of the brain. Absence of these associations in the SSD group may indicate that other factors such as allostatic load, chronic medication use and interrupted educational carrier had larger impact and attenuated the relative contribution of bacterial translocation.

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).

Infections and schizophrenia

This paper provides a critical review of the literature, demonstrating a certain pathogenetic role of various infections, primarily viruses from the herpes and chlamydia groups, in the development and progression of schizophrenia, including published results of the authors’ own long-term studies.

COVID-19-induced psychosis: two case reports and narrative literature review

Introduction: SARS-CoV-2 infection might be presented in many various specific and non-specific manifest and symptoms from different systems. Also, the psychotic symptoms are documented but the explanation for their pathophysiology remains debatable and a complex matter. The main objective of this paper is to present cases of patients without a history of psychiatric disorders who developed the first episode of psychosis during the SARS-CoV-2 infection.

Material and methods: Two cases of not-related patients with no previous psychiatric history developed psychotic episodes during COVID-19 infection. In both cases chronologically first they experienced symptoms of infection, secondly, delusions and psychomotor agitation that required psychiatric hospitalization. Full remission was observed after antipsychotic treatment in both cases.

Results: Even though the pathophysiology of the post-COVID-19 psychiatric symptoms remains unclear, some reports that indicate associations between the infection and the onset of such symptoms. The infection itself, by the induction of cytokine storm followed by the excessive release of pro-inflammatory cytokines, is considered to stimulate the potential onset of the psychosis, however, other factors such as medications used during treatment (with a particular emphasis on glucocorticosteroids) or psychological factors should be considered as well.

Conclusions: Patients infected with SARS-CoV-2 might develop serious psychotic episodes even without a prior psychiatric history. Besides, psychiatric symptoms might be the first the even the only manifestations associated with the active SARSCoV-2 infection which seems to be very challenging especially in cases of rapid psychotic episodes without any clear respiratory symptoms.

Association between toxoplasmosis and bipolar disorder: A systematic review and meta-analysis

BACKGROUND

The relationship between toxoplasma gondii (T. gondii) infection and bipolar disorder (BD) is poorly understood. This review explores this relationship by estimating the strength of the association between the two conditions using data from published studies.

METHODS

Following PRISMA guidelines, we performed a review and meta-analysis of published articles obtained from a systematic search of PubMed, PsycINFO, EMBASE and the Cochrane library up to January 10th, 2021. We included observational studies that compared seroprevalence of IgG class antibodies against T. gondii in patients with a diagnosis of BD with healthy controls. We excluded studies that included <10 participants in each study arm and patients with a serious concomitant medical illness. Discrepancies between the two independent researchers were resolved by consulting a third experienced researcher. Summary data were extracted from published reports. Analysis was conducted using both fixed-effects and random-effects models. The study is registered with PROSPERO number CRD42021237809.

FINDINGS

The search yielded 23 independent studies with a total of 12690 participants (4021 with BD and 8669 controls). Persons with BD had a greater odd of seropositivity with toxoplasmosis than controls, both in the fixed-effects model (OR = 1.34 [95%CI: 1.19 to 1.51]) and the random-effects model (OR = 1.69 [95%CI: 1.21 to 2.36]). No publication bias was detected but reported results showed a high heterogeneity (I2 = 84% [95%CI:77%-89%]).

INTERPRETATION

The findings support the relationship between toxoplasmosis infection and BD and suggests a need for studies designed to explore possible causal relationship. Such studies may also improve our understanding of the pathophysiology of BD and open other avenues for its treatment.

FUNDING

P.O.R. Sardegna F.S.E. 2014-2020.

Could CRP be a differential biomarker of illness stages in schizophrenia? A systematic review and meta-analysis

BACKGROUND

Patients with schizophrenia display peripheral inflammation but the impact of illness phase is not clear. Our meta-analysis investigated the difference in CRP levels between patients with schizophrenia and controls according to their illness phase.

METHODS

After a systematic search, all studies measuring CRP in patients with schizophrenia and controls were included. Standardized mean differences were calculated between patients and controls according to illness phase. The influence of sociodemographic and clinical variables on our results was investigated using a meta-regression analysis.

RESULTS

Fifty studies were included in this meta-analysis. Patients with schizophrenia had higher CRP levels than controls in the acute (p < 0.00001) and stable (p < 0.00001) stage of their disease. Patients with acute exacerbation of schizophrenia had higher CRP levels than stable patients (p = 0.02) but this difference did not persist when considering antipsychotic-medicated patients in both phases. Meta-regressions found that the increase of CRP in acutely ill patients as compared to controls was influenced by age (p < 0.01), BMI (p = 0.01) and first episode (p = 0.02), whereas the increase in CRP levels of stable patients as compared to controls was moderated by BMI (p = 0.004).

CONCLUSIONS

In conclusion, this meta-analysis provides strong evidence that patients with schizophrenia have higher CRP levels than controls, but also show an increase in inflammatory response in the acute stage of the disease as compared to the stable stage. CRP could thus be considered as a state marker and a trait marker of the disease.

Antibody indices of infectious pathogens from serum and cerebrospinal fluid in patients with schizophrenia spectrum disorders

Introduction

Infectious and immunological theories of schizophrenia have been discussed for over a century. Contradictory results for infectious agents in association with schizophrenia spectrum disorders (SSDs) were reported. The rationale of this study was to investigate intrathecal antibody synthesis of the most frequently discussed neurotropic pathogens using a pathogen-specific antibody index (AI) in patients with SSD in comparison to controls.

Methods

In 100 patients with SSD and 39 mentally healthy controls with idiopathic intracranial hypertension (IIH), antibodies against the herpesviruses EBV, CMV, and HSV 1/2 as well as the protozoan Toxoplasma gondii, were measured in paired cerebrospinal fluid (CSF) and serum samples with ELISA-kits. From these antibody concentrations the pathogen-specific AIs were determined with the assumption of intrathecal antibody synthesis at values > 1.5.

Results

No significant difference was detected in the number of SSD patients with elevated pathogen-specific AI compared to the control group. In a subgroup analysis, a significantly higher EBV AI was observed in the group of patients with chronic SSD compared to patients with first-time SSD diagnosis (p = 0.003). In addition, two identified outlier EBV patients showed evidence for polyspecific immune reactions (with more than one increased AI).

Conclusions

Evidence for the role of intrathecal EBV antibody synthesis was found in patients with chronic SSD compared to those first diagnosed. Apart from a possible infectious factor in SSD pathophysiology, the evidence for polyspecific immune response in outlier patients may also suggest the involvement of further immunological processes in a small subgroup of SSD patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-022-00355-7.

Effect of Cytomegalovirus on the Immune System: Implications for Aging and Mental Health

Human cytomegalovirus (HCMV) is a major modulator of the immune system leading to long-term changes in T-lymphocytes, macrophages, and natural killer (NK) cells among others. Perhaps because of this immunomodulatory capacity, HCMV infection has been linked with a host of deleterious effects including accelerated immune aging (premature mortality, increased expression of immunosenescence-linked markers, telomere shortening, speeding-up of epigenetic "clocks"), decreased vaccine immunogenicity, and greater vulnerability to infectious diseases (e.g., tuberculosis) or infectious disease-associated pathology (e.g., HIV). Perhaps not surprisingly given the long co-evolution between HCMV and humans, the virus has also been associated with beneficial effects, such as increased vaccine responsiveness, heterologous protection against infections, and protection against relapse in the context of leukemia. Here, we provide an overview of this literature. Ultimately, we focus on one other deleterious effect of HCMV, namely the emerging literature suggesting that HCMV plays a pathophysiological role in psychiatric illness, particularly depression and schizophrenia. We discuss this literature through the lens of psychological stress and inflammation, two well-established risk factors for psychiatric illness that are also known to predispose to reactivation of HCMV.

Quantitative detection of methylated SOCS-1 in schizophrenia and bipolar disorder considering SOCS-1 -1478CA/del polymorphism and clinical parameters

BACKGROUND

We aimed to investigate the quantitative detection of methylated suppressor of cytokine signaling-1 (SOCS-1) in schizophrenia (SCZ) and bipolar disorder (BD), considering SOCS-1 -1478CA/del polymorphism and clinical parameters.

METHODS

Our research is a case-control study in which 114 patients with SCZ, 86 patients with BD, and 80 volunteers as a healthy group participated. Bisulfite-converted DNA samples were analyzed using the real-time quantitative methylation-specific PCR (qMS-PCR) method to measure the methylation level of the SOCS-1 gene. In addition, SOCS-1 -1478CA/del gene polymorphism was analyzed with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

When the SOCS-1 promoter methylation levels of SCZ and BD patients were compared with the control group, the methylation levels of SCZ and BD were significantly lower than the control group. An earlier age of illness onset was significantly related to the SOCS-1 promoter hypermethylation in DNA samples of SCZ patients. Again, SOCS-1 promoter hypermethylation was significantly associated with the higher Young Mania Rating Scale (YMRS) score in BD patients. While the SOCS-1 CA/CA genotype frequency was significantly higher in the control group than in the BD group, the del/del genotype was significantly related to a higher frequency of rapid cycling and a lower frequency of family history in the BD patient group.

CONCLUSION

In summary, the methylated SOCS-1 quantity in DNA samples of SCZ and BD patients were significantly lower than in control samples. Whereas the SOCS-1 -1478CA/del polymorphism was not related to SCZ, it may be associated with the BD.

Effect of Cytomegalovirus Infection on the Central Nervous System: Implications for Psychiatric Disorders

Cytomegalovirus (CMV) is a common herpesvirus that establishes lifelong latent infections and interacts extensively with the host immune system, potentially contributing to immune activation and inflammation. Given its proclivity for infecting the brain and its reactivation by inflammatory stimuli, CMV is well known for causing central nervous system complications in the immune-naïve (e.g., in utero) and in the immunocompromised (e.g., in neonates, individuals receiving transplants or cancer chemotherapy, or people living with HIV). However, its potentially pathogenic role in diseases that are characterized by more subtle immune dysregulation and inflammation such as psychiatric disorders is still a matter of debate. In this chapter, we briefly summarize the pathogenic role of CMV in immune-naïve and immunocompromised populations and then review the evidence (i.e., epidemiological studies, serological studies, postmortem studies, and recent neuroimaging studies) for a link between CMV infection and psychiatric disorders with a focus on mood disorders and schizophrenia. Finally, we discuss the potential mechanisms through which CMV may cause CNS dysfunction in the context of mental disorders and conclude with a summary of the current state of play as well as potential future research directions in this area.

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.

Gut dysbiosis in severe mental illness and chronic fatigue: a novel trans-diagnostic construct? A systematic review and meta-analysis

Reduced gut-microbial diversity ("gut dysbiosis") has been associated with an anhedonic/amotivational syndrome ("sickness behavior") that manifests across severe mental disorders and represent the key clinical feature of chronic fatigue. In this systematic review and meta-analysis, we investigated differences in proxy biomarkers of gut dysbiosis in patients with severe mental illness and chronic fatigue vs. controls and the association of these biomarkers with sickness behavior across diagnostic categories. Following PRISMA guidelines, we searched from inception to April 2020 for all the studies investigating proxy biomarkers of gut dysbiosis in patients with severe mental illness and chronic fatigue. Data were independently extracted by multiple observers, and a random-mixed model was used for the analysis. Heterogeneity was assessed with the I² index. Thirty-three studies were included in the systematic review; nineteen in the meta-analysis (N = 2758 patients and N = 1847 healthy controls). When compared to controls, patients showed increased levels of zonulin (four studies reporting data on bipolar disorder and depression, SMD = 0.97; 95% Cl = 0.10-1.85; P = 0.03, I² = 86.61%), lipopolysaccharide (two studies reporting data on chronic fatigue and depression, SMD = 0.77; 95% Cl = 0.42-1.12; P < 0.01; I² = 0%), antibodies against endotoxin (seven studies reporting data on bipolar disorder, depression, schizophrenia, and chronic fatigue, SMD = 0.99; 95% CI = 0.27-1.70; P < 0.01, I² = 97.14%), sCD14 (six studies reporting data on bipolar disorder, depression, schizophrenia, and chronic fatigue, SMD = 0.54; 95% Cl 0.16-0.81; P < 0.01, I² = 90.68%), LBP (LBP, two studies reporting data on chronic fatigue and depression, SMD = 0.87; 95% Cl = 0.25-1.48; P < 0.01; I² = 56.80%), alpha-1-antitripsin (six studies reporting data on bipolar disorder, depression, and schizophrenia, SMD = 1.23; 95% Cl = 0.57-1.88; P < 0.01, I²: 89.25%). Elevated levels of gut dysbiosis markers positively correlated with severity of sickness behavior in patients with severe mental illness and chronic fatigue. Our findings suggest that gut dysbiosis may underlie symptoms of sickness behavior across traditional diagnostic boundaries. Future investigations should validate these findings comparing the performances of the trans-diagnostic vs. categorical approach. This will facilitate treatment breakthrough in an area of unmet clinical need.

The relationship between immune and cognitive dysfunction in mood and psychotic disorder: a systematic review and a meta-analysis

BACKGROUND

In psychotic and mood disorders, immune alterations are hypothesized to underlie cognitive symptoms, as they have been associated with elevated blood levels of inflammatory cytokines, kynurenine metabolites, and markers of microglial activation. The current meta-analysis synthesizes all available clinical evidence on the associations between immunomarkers (IMs) and cognition in these psychiatric illnesses.

METHODS

Pubmed, Web of Science, and Psycinfo were searched for peer-reviewed studies on schizophrenia spectrum disorder (SZ), bipolar disorder (BD), or major depressive disorder (MDD) including an association analysis between at least one baseline neuropsychological outcome measure (NP) and one IM (PROSPERO ID:CRD42021278371). Quality assessment was performed using BIOCROSS. Correlation meta-analyses, and random effect models, were conducted in Comprehensive Meta-Analysis version 3 investigating the association between eight cognitive domains and pro-inflammatory and anti-inflammatory indices (PII and AII) as well as individual IM.

RESULTS

Seventy-five studies (n = 29,104) revealed global cognitive performance (GCP) to be very weakly associated to PII (r = -0.076; p = 0.003; I² = 77.4) or AII (r = 0.067; p = 0.334; I² = 38.0) in the combined patient sample. Very weak associations between blood-based immune markers and global or domain-specific GCP were found, either combined or stratified by diagnostic subgroup (GCP x PII: SZ: r = -0.036, p = 0.370, I² = 70.4; BD: r = -0.095, p = 0.013, I² = 44.0; MDD: r = -0.133, p = 0.040, I² = 83.5). We found evidence of publication bias.

DISCUSSION

There is evidence of only a weak association between blood-based immune markers and cognition in mood and psychotic disorders. Significant publication and reporting biases were observed and most likely underlie the inflation of such associations in individual studies.

Delirious mania in a patient with COVID-19 pneumonia

Delirious mania (the coexistence of delirium and mania) is described in the literature but not recognised in standard nosologies. We report a woman in her late 30s, with no psychiatric history, who presented with concurrent symptoms of mania and delirium. She was diagnosed with COVID-19 pneumonia (positive reverse transcription-PCR test). There was no history of substance misuse or concurrent medical illness. CT head scan was normal as were blood investigations, other than elevated inflammatory markers. She received standard treatment for COVID-19 pneumonia and lorazepam and quetiapine to treat her neuropsychiatric symptoms. She made a full recovery after 9 days. She was apyrexial with normal oxygen saturation throughout her illness. The case shows that severe neuropsychiatric symptoms can complicate otherwise mild COVID-19 pneumonia with neuroinflammation being a possible mechanism. A diagnosis of delirious mania appears to better capture the complexity of the presentation than a diagnosis of mania or delirium alone.

The Hippocampal Vulnerability to Herpes Simplex Virus Type I Infection: Relevance to Alzheimer's Disease and Memory Impairment

Herpes simplex virus type 1 (HSV-1) as a possible infectious etiology in Alzheimer’s disease (AD) has been proposed since the 1980s. The accumulating research thus far continues to support the association and a possible causal role of HSV-1 in the development of AD. HSV-1 has been shown to induce neuropathological and behavioral changes of AD, such as amyloid-beta accumulation, tau hyperphosphorylation, as well as memory and learning impairments in experimental settings. However, a neuroanatomical standpoint of HSV-1 tropism in the brain has not been emphasized in detail. In this review, we propose that the hippocampal vulnerability to HSV-1 infection plays a part in the development of AD and amnestic mild cognitive impairment (aMCI). Henceforth, this review draws on human studies to bridge HSV-1 to hippocampal-related brain disorders, namely AD and aMCI/MCI. Next, experimental models and clinical observations supporting the neurotropism or predilection of HSV-1 to infect the hippocampus are examined. Following this, factors and mechanisms predisposing the hippocampus to HSV-1 infection are discussed. In brief, the hippocampus has high levels of viral cellular receptors, neural stem or progenitor cells (NSCs/NPCs), glucocorticoid receptors (GRs) and amyloid precursor protein (APP) that support HSV-1 infectivity, as well as inadequate antiviral immunity against HSV-1. Currently, the established diseases HSV-1 causes are mucocutaneous lesions and encephalitis; however, this review revises that HSV-1 may also induce and/or contribute to hippocampal-related brain disorders, especially AD and aMCI/MCI.

Schizophrenia: a classic battle ground of nature versus nurture debate

Much has been learned about the etiology and pathogenesis of schizophrenia since the term was first used by Eugene Bleuler over a century ago to describe one of the most important forms of major mental illness to affect mankind. Both nature and nurture feature prominently in our understanding of the genesis of the overall risk of developing schizophrenia. We now have a firm grasp of the broad structure of the genetic architecture and several key environmental risk factors have been identified and delineated. However, much of the heritability of schizophrenia remains unexplained and the reported environmental risk factors do not explain all the variances not attributable to genetic risk factors. The biggest problem at present is that our understanding of the causal mechanisms involved is still in its infancy. In this review, we describe the extent and limits of our knowledge of the specific genetic/constitutional and non-genetic/environmental factors that contribute to the overall risk of schizophrenia. We suggest novel methods may be required to understand the almost certainly immensely complex multi-level causal mechanisms that contribute to the generation of the schizophrenia phenotype.

Mood Disorders and Increased Risk of Noncommunicable Disease in Adults With HIV

BACKGROUND

People living with HIV (PLWH) experience high rates of mood disorders (major depression and bipolar affective disorder) which in the general population have been associated with noncommunicable disease (NCD) risk. We examined whether prevalent mood disorders are associated with incident NCDs and multimorbidity (accumulation of ≥2 NCDs) in PLWH.

SETTING

Adult HIV clinic cohort in Nashville, Tennessee, between 1998 and 2015.

METHODS

PLWH with ≥1 year of follow-up in the clinic were assessed for cardiovascular disease, metabolic syndrome (any 3 of hypertension, hyperlipidemia, diabetes, or obesity), chronic kidney and liver disease, non-AIDS-defining cancers, and dementia. Only mood disorders documented during the first year of care were included. Cumulative incidence and adjusted subhazard ratios (aSHRs) were calculated for risk of NCDs and multimorbidity with death as a competing risk. Multivariable Cox models estimated mortality risk after multimorbidity.

RESULTS

Of 4140 adults, 24% had a mood disorder diagnosed in the first year of care, 51% had ≥1 NCD at baseline, and there were 2588 incident NCDs during the study period. Mood disorders were associated with increased risk of first NCD (aSHR = 1.29, 95% confidence interval: 1.06 to 1.57), incident multimorbidity (aSHR ranging from 1.04 to 1.42), and metabolic syndrome (aSHR = 1.29, 95% confidence interval: 1.02 to 1.64). Mood disorders were not conclusively associated with mortality risk after multimorbidity.

CONCLUSIONS

PLWH with mood disorders were at increased risk of incident NCDs and multimorbidity, particularly metabolic syndrome. Focused prevention and treatment of NCDs may reduce the burden of multimorbidity in this high-risk group.

From conifers to cognition: Microbes, brain and behavior

A diversity of bacteria, protozoans and viruses ("endozoites") were recently uncovered within healthy tissues including the human brain. By contrast, it was already recognized a century ago that healthy plants tissues contain abundant endogenous microbes ("endophytes"). Taking endophytes as an informative precedent, we overview the nature, prevalence, and role of endozoites in mammalian tissues, centrally focusing on the brain, concluding that endozoites are ubiquitous in diverse tissues. These passengers often remain subclinical, but they are not silent. We address their routes of entry, mechanisms of persistence, tissue specificity, and potential to cause long-term behavioral changes and/or immunosuppression in mammals, where rabies virus is the exemplar. We extend the discussion to Herpesviridae, Coronaviridae, and Toxoplasma, as well as to diverse bacteria and yeasts, and debate the advantages and disadvantages that endozoite infection might afford to the host and to the ecosystem. We provide a clinical perspective in which endozoites are implicated in neurodegenerative disease, anxiety/depression, and schizophrenia. We conclude that endozoites are instrumental in the delicate balance between health and disease, including age-related brain disease, and that endozoites have played an important role in the evolution of brain function and human behavior.

Latent infection, inflammatory markers and suicide attempt history in depressive disorders

BACKGROUND

Numerous reports have described increased rates of exposure to Toxoplasma gondii levels in individuals with a history of suicide attempts in comparison with well controls, or psychiatrically ill individuals, with no suicide attempt history. Such findings suggest that the behavioral effects this parasite exerts on rodent hosts extends to humans though few studies have searched for underlying mechanisms.

METHODS

The present study compared 96 patients with an active depressive disorder and a history of at least two suicide attempts to 126 depressed patients with no history of suicide attempts by IgG and IgM levels of Toxoplasma gondii and cytomegalovirus (CMV). The groups were also compared by IL_1b, TNF-alpha, CRP, IL_6, and IL_1ra titers.

RESULTS

Toxoplasma gondii IgM levels were higher, and seropositivity more likely, in the suicide attempt group. CMV IgG levels were also higher among suicide attempters. Several of these immunoglobulin measures were more robustly associated with the number of suicide attempts than with the dichotomy of suicide attempter and non-attempter. These two antibody levels were also additive in their association with suicide attempter status. IL_1a levels were lower in suicide attempters and correlated negatively with levels of antibodies to Toxoplasma gondii and CMV.

LIMITATIONS

These include a sample size insufficient to explore differences across mood disorder diagnoses or demographic groupings.

CONCLUSIONS

These results indicate that exposure to common infectious agents such as Toxoplasma gondii and CMV are associated with increased risk of suicide attempts but the mechanism of association does not appear to involve the activation of cytokines. Elucidation of the mechanisms which define the relationship between infections and suicide attempts may lead to new methods for the prediction and prevention of suicide attempts.

Neurodevelopmental Factors in Schizophrenia

The onset of schizophrenia is usually in late adolescence or early adulthood. However, accumulating evidence has suggested that the disease condition is an outcome of gene-environment interactions that act in neural development during early life and adolescence. Some children who later develop schizophrenia have early developmental and educational and social challenges. Some patients with schizophrenia have an abundance of nonspecific neurologic soft signs and minor physical anomalies. Adolescence is a sensitive period of increased neuronal plasticity. It is important to consider early detection and intervention from the prodromal stage to early disease to prevent its devastating long-term consequences.

Functional Neuroimaging in Psychiatry-Aiding in Diagnosis and Guiding Treatment. What the American Psychiatric Association Does Not Know

While early efforts in psychiatry were focused on uncovering the neurobiological basis of psychiatric symptoms, they made little progress due to limited ability to observe the living brain. Today, we know a great deal about the workings of the brain; yet, none of this neurobiological awareness has translated into the practice of psychiatry. The categorical system which dominates psychiatric diagnosis and thinking fails to match up to the real world of genetics, sophisticated psychological testing, and neuroimaging. Nevertheless, the American Psychiatric Association (APA) recently published a position paper stating that neuroimaging provided no benefit to the diagnosis and treatment of psychiatric disorders. Using the diagnosis of depression as a model, we illustrate how setting aside the unrealistic expectation of a pathognomonic "fingerprint" for categorical diagnoses, we can avoid missing the biological and, therefore, treatable contributors to psychopathology which can and are visualized using functional neuroimaging. Infection, toxicity, inflammation, gut-brain dysregulation, and traumatic brain injury can all induce psychiatric manifestations which masquerade as depression and other psychiatric disorders. We review these and provide illustrative clinical examples. We further describe situations for which single photon emission computed tomography (SPECT) and positron emission tomography (PET) functional neuroimaging already meet or exceed the criteria set forth by the APA to define a neuroimaging biomarker, including the differential diagnosis of Alzheimer's disease and other dementias, the differential diagnosis of ADHD, and the evaluation of traumatic brain injury. The limitations, both real and perceived, of SPECT and PET functional neuroimaging in the field of psychiatry are also elaborated. An important overarching concept for diagnostic imaging in all its forms, including functional neuroimaging, is that imaging allows a clinician to eliminate possibilities, narrow the differential diagnosis, and tailor the treatment plan. This progression is central to any medical diagnostic process.

Schizophrenia, Bipolar Disorder, and Alzheimer's Disease are not Causal Factors of Bone Mineral Density: A Mendelian Randomization Analysis

Until recently, it remains unclear whether schizophrenia, bipolar disorder (BD), and Alzheimer's disease (AD) is associated with bone mineral density (BMD). We aimed to investigate the causal effects of schizophrenia, BD and AD on BMD with Mendelian randomization (MR) analysis. Single-nucleotide polymorphisms (SNPs) strongly associated with these three neuropsychiatric diseases as instrumental variables were selected from genome-wide association studies in the MR Base database. We analyzed the effects of these SNPs on the femoral neck BMD (FN-BMD), lumbar spine BMD (LS-BMD) and forearm BMD (FA-BMD), and evaluated the heterogeneities and pleiotropy of these genetic variants. We also evaluated the potential confounding factors in the association between these three neuropsychiatric diseases and the BMD level. It was found that none of these genetic variants were significantly associated with BMD or confounding factors. Using these genetic variants, we did not find statistically significant causal effects of per unit increase in the log-odds of having schizophrenia, BD or AD with FN-BMD, LS-BMD and FA-BMD changes (e.g. schizophrenia and FN-BMD, MR-Egger OR 0.9673, 95% CI 0.8382 to 1.1163, p = 0.6519). The MR results also revealed that directional pleiotropy was unlikely to bias the causality (e.g., schizophrenia and FN-BMD, intercept = 0.0023, p = 0.6887), and no evidence of heterogeneity was found between the genetic variants (e.g., schizophrenia and FN-BMD, MR-Egger Q = 46.1502, I² = 0.0899, p = 0.3047). Our MR study did not support causal effects of increased risk of schizophrenia, BD and AD status with BMD level.

In Vitro and In Vivo Models for the Investigation of Potential Drugs Against Schizophrenia

Schizophrenia (SZ) is a complex psychiatric disorder characterized by positive, negative, and cognitive symptoms, and is not satisfactorily treated by current antipsychotics. Progress in understanding the basic pathomechanism of the disease has been hampered by the lack of appropriate models. In order to develop modern drugs against SZ, efficient methods to study them in in vitro and in vivo models of this disease are required. In this review a short presentation of current hypotheses and concepts of SZ is followed by a description of current progress in the field of SZ experimental models. A critical discussion of advantages and limitations of in vitro models and pharmacological, genetic, and neurodevelopmental in vivo models for positive, negative, and cognitive symptoms of the disease is provided. In particular, this review concerns the important issue of how cellular and animal systems can help to meet the challenges of modeling the disease, which fully manifests only in humans, as experimental studies of SZ in humans are limited. Next, it is emphasized that novel clinical candidates should be evaluated in animal models for treatment-resistant SZ. In conclusion, the plurality of available in vitro and in vivo models is a consequence of the complex nature of SZ, and there are extensive possibilities for their integration. Future development of more efficient antipsychotics reflecting the pleiotropy of symptoms in SZ requires the incorporation of various models into one uniting model of the multifactorial disorder and use of this model for the evaluation of new drugs.

The aetiology of social deficits within mental health disorders: The role of the immune system and endogenous opioids

The American National Institute for Mental Health (NIMH) has put out a set of research goals that include a long-term plan to identify more reliable endogenous explanations for a wide variety of mental health disorders (Insel, 2013). In response to this, we have identified a major symptom that underlies multiple mental health disorders - social bonding dysfunction. We suggest that endogenous opioid abnormalities can lead to altered social bonding, which is a symptom of various mental health disorders, including depression, schizophrenia and ASD. This article first outlines how endogenous opioids play a role in social bonding. Then we show their association with the body's inflammation immune function, and review recent literature linking inflammation to mental health 'immunophenotypes'. We finish by explaining how these immunophenotypes may be caused by alterations in the endogenous opioid system. This is the first overview of the role of inflammation across multiple disorders where we provide a biochemical explanation for why immunophenotypes might exist across diagnoses. We propose a novel mechanism of how the immune system may be causing 'sickness-type' behaviours (fatigue, appetite change, social withdrawal and inhibited motivation) in those who have these immunophenotypes. We hope that this novel aetiology can be used as a basis for future research in mental health.

Cytomegalovirus Seropositivity and Suicidal Behavior: A Mini-Review

Background and objectives: In recent years, a growing body of research has focused on identifying possible biological markers for suicidal behavior, including infective and immunological markers. In this paper, our aim was to review available evidence concerning the association between cytomegalovirus (CMV) infection and suicide. Materials and Methods: A systematic search according to the PRISMA statement was performed on Pubmed. After the screening procedure, we identified five relevant papers. Results: We found inconsistent evidence linking CMV infection and suicide, with some papers reporting an association between CMV seropositivity and suicidal behavior, and others not finding the association. Conclusions: With the evidence available presently, it is not possible to infer whether there is a correlation between suicide and CMV infection.

The association between antibodies to neurotropic pathogens and bipolar disorder : A study in the Dutch Bipolar (DB) Cohort and meta-analysis

Exposure to neurotropic pathogens has been hypothesized to be a risk factor for the development of bipolar disorder (BD). However, evidence so far is inconsistent. We, therefore, analyzed the seroprevalence and titer levels of IgG antibodies against several herpesviruses and Toxoplasma gondii (T. gondii) in plasma of 760 patients with a bipolar disorder, 144 first-degree matched relatives and 132 controls of the Dutch Bipolar (DB) Cohort using ELISA. In addition, we performed a literature-based meta-analysis on the seroprevalence of IgG antibodies against these pathogens (n = 14). Our results in the DB Cohort and subsequent meta-analysis (n = 2364 BD patients, n = 5101 controls) show no association between exposure to herpesviruses and bipolar disorder (HSV-1 [adjusted OR 0.842, 95% CI 0.567-1.230], HSV-2 [adjusted OR 0.877, 95% CI 0.437-1.761], CMV [adjusted OR 0.884 95% CI 0.603-1.295], EBV [adjusted OR 0.968 95% CI 0.658-1.423]). In the DB Cohort, we did not find an association between bipolar disorder and T. gondii titer or seroprevalence either [adjusted OR 1.018, 95% CI 0.672-1.542]. The overall OR was not significant for T. gondii [OR: 1.4, 95% CI 0.95-1.90, p = 0.09), but subgroup analyses in age groups below 40 years showed a significantly increased seroprevalence of T. gondii IgGs in BD [OR: 1.8 (95% CI 1.10-2.89, p = 0.021]. Our meta-analysis indicates that T. gondii exposure may be a risk factor for BD in certain subpopulations.

Assessment of cognitive impairment in HSV-1 positive schizophrenia and bipolar patients: Systematic review and meta-analysis

A common characteristic among schizophrenia and bipolar disorder patients is cognitive dysfunction, especially for memory and attention. Recent evidence has suggested that cognitive impairment in schizophrenia and bipolar disorder patients could be associated with herpes simplex virus 1 (HSV-1) infection, due to the ability of HSV-1 to infect neurons in the temporal lobe, which plays a key role in the formation of memory and processing of sensory input. The objective of this review is to analyze the aggregate neuropsychological testing data from previous studies regarding the impact of HSV-1 infection on cognitive function in schizophrenia and bipolar disorder. A systematic literature search generated a total of 379 articles; 12 full-text case control and cross-sectional studies met the eligibility criteria to be included in the review. Pooled effects assessed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) total scores and the three index scores for immediate memory, delayed memory, and attention in a random effects model. The overall effect for RBANS total score was in favor of the HSV-1 positive group (z = 3.10, p = 0.002). A statistically significant overall effect of cognitive impairment for memory and attention indices was in favor of HSV positive schizophrenia patients (z = 5.95 p < 0.00001). The findings from the meta-analysis suggest that serological evidence of HSV-1 infection has a significant impact on cognitive function with small to moderate effect sizes (-0.23 to -0.49), particularly affecting memory and attention, in schizophrenia and bipolar patients.

120th Anniversary of the Kraepelinian Dichotomy of Psychiatric Disorders

PURPOSE OF REVIEW

Emil Kraepelin, in 1899, proposed a dichotomy of psychiatric disorders into "dementia praecox," further called schizophrenia, and "manisch-depressives Irresein," now conceptualized as a bipolar disorder. The purpose of the review is to show both similarities and differences between disorders involved in this dichotomy, speaking for and against the idea.

RECENT FINDINGS

On the molecular genetic side, there are data for both a genetic overlap and genetic differences between these two illnesses. Among pharmacological treatment, lithium, valproates, and carbamazepine present evidence for Kraepelinian dichotomy while atypical antipsychotics speak against this. The recent results for similarities and differences in the immune system, cognitive functions, and neurodevelopmental mechanisms have also been presented and discussed. As of 2019, the Kraepelinian dichotomy has been still partly valid although the results of recent clinical, neurobiological, and pharmacological studies provided a large number of data for an intermediate space between schizophrenia and bipolar disorder.

Large-scale study of Toxoplasma and Cytomegalovirus shows an association between infection and serious psychiatric disorders

BACKGROUND

Common infectious pathogens have been associated with psychiatric disorders, self-violence and risk-taking behavior.

METHODS

This case-control study reviews register data on 81,912 individuals from the Danish Blood Donor Study to identify individuals who have a psychiatric diagnosis (N = 2591), have attempted or committed suicide (N = 655), or have had traffic accidents (N = 2724). For all cases, controls were frequency matched by age and sex, resulting in 11,546 participants. Plasma samples were analyzed for immunoglobulin G (IgG) antibodies against Toxoplasma gondii and cytomegalovirus (CMV).

RESULTS

T. gondii was detected in 25·9% of the population and was associated with schizophrenia (odds ratio [OR], 1·47; 95% confidence interval [CI], 1·03-2·09). Accounting for temporality, with pathogen exposure preceding outcome, the association was even stronger (IRR, 2·78; 95% CI, 1·27-6·09). A very weak association between traffic accident and toxoplasmosis (OR, 1·11; 95% CI, 1·00-1·23, p = 0.054) was found. CMV was detected in 60·8% of the studied population and was associated with any psychiatric disorder (OR, 1·17; 95% CI, 1·06-1·29), but also with a smaller group of neurotic, stress-related, and somatoform disorders (OR, 1·27; 95% CI, 1·12-1·44), and with attempting or committing suicide (OR, 1·31; 95% CI, 1·10-1·56). Accounting for temporality, any psychiatric disorder (IRR, 1·37; 95% CI, 1·08-1·74) and mood disorders (IRR, 1·43; 95% CI, 1·01-2·04) were associated with exposure to CMV. No association between traffic accident and CMV (OR, 1·06; 95% CI, 0·97-1·17) was found.

CONCLUSIONS

This large-scale serological study is the first study to examine temporality of pathogen exposure and to provide evidence of a causal relationship between T. gondii and schizophrenia, and between CMV and any psychiatric disorder.

Neutrophil/lymphocyte ratio: Can a non-specific marker of inflammation helps to confirm the inflammatory hypothesis of the serious mental diseases? A case-control study

BACKGROUND

The hypotheses of autoimmune, allergic or infectious etiology of severe mental illness have been reported in the scientific literature repeatedly. The main objective of this work is to study the relationship of inflammatory, autoimmunity or recent infection markers with the fact of suffering Severe Mental Disorders (SMD).

METHODS

In the present case-control study, adult patients with a diagnosis of SMD were compared with controls who underwent routine health checks that included analytical control. Cases with psychosis substance-induced and controls with diagnosis of any psychiatric illness were excluded. In both groups, patients with chronic inflammatory diseases or intercurrent infectious disease were also excluded. A set of common analytical parameters, markers of infectious diseases and inflammatory markers were retrieved for both groups, as well as demographic and clinical data.

RESULTS

A total of 212 subjects (81 cases and 131 controls) were recruited. From cases, 70 (86.4%) have a diagnosis of Schizophrenia Disease (SD) and 11 (13.6%) of Schizoaffective Disorder (SAD). In the multivariate model the female sex (OR 0.24, 95% CI 0.12-0.46) and the neutrophil-lymphocyte ratio (OR 3.00, 95% CI 1.91-4.70) were associated with the fact of being case.

CONCLUSIONS

Patients with SMD seem to have higher inflammatory markers compared to the general population, being the neutrophil-lymphocyte ratio, the marker associated with more strength. The role of inflammatory processes in the etiology of this type of disorders, if confirmed, opens interesting and innovative therapeutic possibilities.

Metabolomics Biomarkers for Precision Psychiatry

The treatment of psychiatric disorders remains a significant challenge in part due to imprecise diagnostic criteria and incomplete understanding of the molecular pathology involved. Current diagnostic and pharmacological treatment guidelines use a uniform approach to address each disorder even though psychiatric clinical presentation and prognosis within a disorder are known to be heterogeneous. Limited therapeutic success highlights the need for a precision medicine approach in psychiatry, termed precision psychiatry. To practice precision psychiatry, it is essential to research and develop multiple omics-based biomarkers that consider environmental factors and careful phenotype determination. Metabolomics, which lies at the endpoint of the "omics cascade," allows for detection of alterations in systems-level metabolites within biological pathways, thereby providing insights into the mechanisms that underlie various physiological conditions and pathologies. The eicosanoids, a family of metabolites derived from oxygenated polyunsaturated fatty acids, play a key role in inflammatory mechanisms and have been implicated in psychiatric disorders such as anorexia nervosa and depression. This review (1) provides background on the current clinical challenges of psychiatric disorders, (2) gives an overview of metabolomics application as a tool to develop improved biomarkers for precision psychiatry, and (3) summarizes current knowledge on metabolomics and lipidomic findings in common psychiatric disorders, with a focus on eicosanoids. Metabolomics is a promising tool for precision psychiatry. This research has great potential for both discovering biomarkers and elucidating molecular mechanisms underlying psychiatric disorders.

White matter microstructure alterations correlate with terminally differentiated CD8+ effector T cell depletion in the peripheral blood in mania: Combined DTI and immunological investigation in the different phases of bipolar disorder

BACKGROUND

White matter (WM) microstructural abnormalities and, independently, signs of immunological activation were consistently demonstrated in bipolar disorder (BD). However, the relationship between WM and immunological alterations as well as their occurrence in the various phases of BD remain unclear.

METHOD

In 60 type I BD patients - 20 in manic, 20 in depressive, 20 in euthymic phases - and 20 controls we investigated: (i) diffusion tensor imaging (DTI)-derived fractional anisotropy (FA), radial diffusivity (RD) and axial diffusivity (AD) using a tract-based spatial statistics (TBSS) approach; (ii) circulating T cell subpopulations frequencies, as well as plasma levels of different cytokines; (iii) potential relationships between WM and immunological data.

RESULTS

We found: (i) a significant widespread combined FA-RD alteration mainly in mania, with involvement of the body of corpus callosum (BCC) and superior corona radiata (SCR); (ii) significant increase in CD4+ T cells as well as significant decrease in CD8+ T cells and their subpopulations effector memory (CD8+ CD28-CD45RA-), terminal effector memory (CD8+ CD28-CD45RA+) and CD8+ IFNγ+ in mania; (iii) a significant relationship between WM and immunological alterations in the whole cohort, and a significant correlation of FA-RD abnormalities in the BCC and SCR with reduced frequencies of CD8+ terminal effector memory and CD8+ IFNγ+ T cells in mania only.

CONCLUSIONS

Our data show a combined occurrence of WM and immunological alterations in mania. WM abnormalities highly correlated with reduction in circulating CD8+ T cell subpopulations that are terminally differentiated effector cells prone to tissue migration, suggesting that these T cells could play a role in WM alteration in BD.

Exploring the associations of herpes simplex virus infection and cognitive dysfunction in schizophrenia: Studies in India

BACKGROUND

Cognitive dysfunctions being core features of schizophrenia (SZ), cause disability, increase burden and are refractory to treatment. Viral infections are not risk factors for SZ, but growing evidence indicates infection with some neurotropic viruses, particularly Herpes simplex virus type 1 (HSV -1) as a risk factor for cognitive dysfunction.

STUDIES IN INDIA

Three research studies in India are described. In the first, participants were evaluated for HSV-1 infection and cognitive functions (cases 198 and controls 100). In the second, patients and normal nonpsychotic control individuals were examined at baseline and followed up over 1-3 years (cases 138 and controls 88). In the third, a randomized, double-blind placebo-controlled antipsychotic adjunctive trial was conducted to examine the effect of anti-viral drug valacyclovir over 16 weeks on cognitive functioning (valacyclovir 30; placebo 32, treatment for 16 weeks).

RESULTS OF INDIAN STUDIES

Cross-sectional study: HSV-1 infection was associated with modest dysfunction, especially on attention (accuracy) and spatial processing (speed).

LONGITUDINAL STUDY

HSV-1 seropositive participants had lower scores at baseline on 6/16 measures, regardless of SZ diagnoses. At follow-up, there was a significant decline in HSV-1-positive participants for abstraction and mental flexibility and emotion discrimination.

RANDOMIZED CONTROLLED TRIAL

Significantly, greater improvement in accuracy index of emotion discrimination in the valacyclovir-treated versus placebo sample was found.

CONCLUSIONS

Indian studies are consistent with a causative role for HSV-1 in cognitive dysfunction regardless of SZ diagnosis; more rigorous studies of the causal hypothesis are needed, particularly larger randomized controlled trials.

Coinfections and comorbidities in African health systems: At the interface of infectious and noninfectious diseases

There is a disease epidemiological transition occurring in Africa, with increasing incidence of noninfectious diseases, superimposed on a health system historically geared more toward the management of communicable diseases. The persistence and sometimes emergence of new pathogens allows for the occurrence of coinfections and comorbidities due to both infectious and noninfectious diseases. There is therefore a need to rethink and restructure African health systems to successfully address this transition. The historical focus of more health resources on infectious diseases requires revision. We hypothesise that the growing burden of noninfectious diseases may be linked directly and indirectly to or further exacerbated by the existence of neglected tropical diseases (NTDs) and other infectious diseases within the population. Herein, we discuss the health burden of coinfections and comorbidities and the challenges to implementing effective and sustainable healthcare in Africa. We also discuss how existing NTD and infectious disease intervention programs in Africa can be leveraged for noninfectious disease intervention. Furthermore, we explore the potential for new technologies-including artificial intelligence and multiplex approaches-for diagnosis and management of chronic diseases for improved health provision in Africa.

Monocyte activation detected prior to a diagnosis of schizophrenia in the US Military New Onset Psychosis Project (MNOPP)

Low-grade inflammation is present in some cases of schizophrenia, particularly in the early stages of this disorder. The inflammation source is not known but may be the result of dysbiotic processes occurring in the gut. We examined peripheral biomarkers of bacterial translocation, soluble CD14 (sCD14) and lipopolysaccharide binding protein (LBP), and of general inflammation, C-reactive protein (CRP), in a unique, pre-onset study of schizophrenia. This sample was composed of 80 case-control matched pairs of US military service members from whom blood samples were obtained at time of entry to service, before a psychiatric diagnosis was made. Elevated levels of sCD14 in individuals who were subsequently diagnosed with schizophrenia generated odds ratios of 1.22 for association with disease (p<0.02). Conversely, LBP levels for those who developed schizophrenia were unchanged or very marginally decreased compared to controls (p=0.06). No significant changes were found for CRP in schizophrenia compared with their matched controls. This diversity of patterns suggests that a dysregulated immune system is present prior to a diagnosis of schizophrenia. In particular, sCD14 elevation and discordant LBP decrease in cases support a more generalized monocyte activation rather than a specific translocation of gut bacteria into circulation. The corresponding absence of general inflammation as measured by CRP may indicate that this monocyte activation or related immune dysfunction precedes the early inflammatory stage frequently evident in schizophrenia.

Translocator protein (TSPO) and stress cascades in mouse models of psychosis with inflammatory disturbances

Changes in inflammatory cascades have been implicated in the underlying pathophysiology of psychosis. Translocator protein 18 kDa (TSPO) has been used to assess neuroinflammatory processes in psychotic disorders. Nonetheless, it is unclear whether TSPO, a mitochondrial protein, can be interpreted as a general marker for inflammation in diseases involving psychosis. To address this question, we investigated TSPO signaling in representative mouse models for psychosis with inflammatory disturbances. The maternal immune activation and cuprizone short-term exposure models show different TSPO signaling. Furthermore, we observed similarities and differences in their respective stress pathways including stress hormone signaling and oxidative stress that are functionally interconnected with the inflammatory responses. We propose that more careful studies of TSPO distribution in neuroinflammation and other stress cascades associated with psychotic symptoms will allow us to understand the biological mechanisms underlying psychosis-related behaviors.

Serum levels of interleukin 6 in schizophrenic patients during treatment augmentation with sarcosine (results of the PULSAR study)

OBJECTIVE

Augmentation of sarcosine, a natural inhibitor of the glycine transporter type I, normalizes glutamatergic neurotransmission, having beneficial impact on primary negative symptoms in schizophrenia and may also influence immune system and interleukin 6 (IL-6) levels.

AIM

Finding a relationship between initial IL-6 serum concentrations or its changes and severity of symptoms as a result of sarcosine addition to stable antipsychotic treatment.

METHOD

Fifity-eight individuals with schizophrenia with predominantly negative symptoms completed a 6-month randomized, double-blind placebo-controlled prospective study. Patients received 2 g of sarcosine (n = 29) or placebo (n = 30) daily per os. We measured IL-6 levels and severity of symptoms at the beginning, after 6 weeks and 6 months. As main clinical tools, we used Positive and Negative Syndrome Scale (PANSS) and Calgary depression scale for schizophrenia (CDSS).

RESULTS

Augmentation with sarcosine had no effect on IL-6 serum levels in all time points. We noted significant improvements in negative symptoms, general psychopathology, and total PANSS score in the sarcosine group. We found correlation of initial serum IL-6 with severity of positive symptoms and negative association between IL-6 levels reduction and positive symptoms reduction.

CONCLUSIONS

Sarcosine does not significantly affect IL-6 concentrations but IL-6 may be involved in mechanisms related to the presence of positive symptoms.

Association between virus exposure and depression in US adults

Mood disorders are common mental illnesses. Among the factors associated with major depression are exposures to infectious diseases including hepatitis C, influenza, varicella-zoster, and herpes viruses. In this study, we sought to evaluate further associations between viral exposure and depression. From the US Center for Disease Control's National Health and Nutrition Examination Survey, we obtained data about depression status, antidepressant use, exposure to hepatitis A, hepatitis B, herpes simplex virus type 1, herpes simplex virus type 2, human immunodeficiency virus, and cytomegalovirus, and sociodemographic variables and evaluated associations between depression and viral exposure in adjusted multivariable models. Herpes simplex virus type 2 was associated with an increased risk of depression, whereas hepatitis A, hepatitis B, and herpes simplex virus type 1 were not. Higher cytomegalovirus antibody levels were associated with depression in subjects seropositive for cytomegalovirus. In conclusion, exposure to herpes simplex virus type 2 and possibly cytomegalovirus are associated with depression in an adult US sample.