Infectious agents associated with schizophrenia: a meta-analysis

Paliperidone reverts Toll-like receptor 3 signaling pathway activation and cognitive deficits in a maternal immune activation mouse model of schizophrenia

The pathophysiology of psychotic disorders is multifactorial, including alterations in the immune system caused by exogenous or endogenous factors. Epidemiological and experimental studies indicate that infections during the gestational period represent a risk factor to develop schizophrenia (SZ) along lifetime. Here, we tested the hypothesis that the antipsychotic paliperidone regulates immune-related brain effects in an experimental model of SZ. A well described prenatal immune activation model of SZ in mice by maternal injection of the viral mimetic poly(I:C) during pregnancy was used. Young-adult offspring animals (60PND) received paliperidone ip (0.05 mg/kg) for 21 consecutive days. One day after last injection, animals were submitted to a cognitive test and brain frontal cortex (FC) samples were obtained for biochemical determinations. The adults showed an activated innate immune receptor TLR-3 signaling pathway, oxidative/nitrosative stress and accumulation of pro-inflammatory mediators such as nuclear transcription factors (i.e., NFκB) and inducible enzymes (i.e., iNOS) in FC. Chronic paliperidone blocked this neuroinflammatory response possibly by the synergic activation and preservation of endogenous antioxidant/anti-inflammatory mechanisms such as NRF2 and PPARγ pathways, respectively. Paliperidone administration also stimulated the alternative polarization of microglia to the M2 anti-inflammatory profile. In addition, paliperidone treatment improved spatial working memory deficits of this SZ-like animal model. In conclusion, chronic administration of paliperidone to young-adult mice prenatally exposed to maternal immune (MIA) challenge elicits a general preventive anti-inflammatory/antioxidant effect at both intracellular and cellular polarization (M1/M2) level in FC, as well as ameliorates specific cognitive deficits.

The Major Histocompatibility Complex (MHC) in Schizophrenia: A Review

Epidemiological studies and mouse models suggest that maternal immune activation, induced clinically through prenatal exposure to one of several infectious diseases, is a risk factor in the development of schizophrenia. This is supported by the strong genetic association established by genome wide association studies (GWAS) between the human leukocyte antigen (HLA) locus and schizophrenia. HLA proteins (also known in mice as the major histocompatibility complex; MHC) are mediators of the T-lymphocyte responses, and genetic variability is well-established as a risk factor for autoimmune diseases and susceptibility to infectious diseases. Taken together, the findings strongly suggest that schizophrenia risk in a subgroup of patients is caused by an infectious disease, and/or an autoimmune phenomenon. However, this view may be overly simplistic. First, MHC proteins have a non-immune effect on synaptogenesis by modulating synaptic pruning by microglia and other mechanisms, suggesting that genetic variability could be compromising this physiological process. Second, some GWAS signals in the HLA locus map near non-HLA genes, such as the histone gene cluster. On the other hand, recent GWAS data show association signals near B-lymphocyte enhancers, which lend support for an infectious disease etiology. Thus, although the genetic findings implicating the HLA locus are very robust, how genetic variability in this region leads to schizophrenia remains to be elucidated.

Comorbidity of schizophrenia and infection: a population-based cohort study

PURPOSE

In this paper, we investigate the hypothesis that there is an overlap between infection and schizophrenia. Infections have been identified as a risk factor for schizophrenia, but the possible overlap between schizophrenia and infections remains unidentified so far. Here, we describe the use of the comorbidity index, a method for objectively integrating associations into a single measure estimating overlap.

METHODS

Data were drawn from three population-based registers, the Civil Registration Register, the Danish Psychiatric Central Research Register, and the Danish National Hospital Register. We selected a cohort of 1,403,183 persons born in Denmark 1977-2002.

RESULTS

Our results indicate that persons who have had a hospital contact with an infection (IRR 1.53, CI 1.46-1.61) are more likely to develop schizophrenia than persons who have not had such a contact. Persons who have had a diagnosis with schizophrenia are more likely to have had a hospital contact with an infection (IRR 1.73, 95 % CI 1.57-1.91) than persons who have had no schizophrenia diagnosis. A comorbidity index of 1.40 (95 % CI 1.34-1.46) was found, indicating an overlap between schizophrenia and infection.

CONCLUSION

Our findings indicate that schizophrenia and infections overlap and that they share risk factors. The comorbidity index showed that the co-occurrence of schizophrenia and infection was 40 % higher than if the two disorders had occurred independently. Although the incidence of schizophrenia and infection was associated with each factor, the overlap could not be explained by urbanicity, parental history of psychiatric admission and infection.

Transcriptome sequencing of the choroid plexus in schizophrenia

The choroid plexus (CP) has a key role in maintaining brain homeostasis by producing cerebrospinal fluid (CSF), by mediating transport of nutrients and removing metabolic products from the central nervous system and by responding to peripheral inflammatory signals. Although abnormal markers of immune response and inflammation are apparent in individuals with schizophrenia, the CP of these individuals has not been characterized. We therefore sequenced mRNA from the CP from two independent collections of individuals with schizophrenia and unaffected controls. Genes related to immune function and inflammation were upregulated in both collections. In addition, a co-expression module related to immune/inflammation response that was generated by combining mRNA-Seq data from both collections was significantly associated with disease status. The immune/inflammation-related co-expression module was positively correlated with levels of C-reactive protein (CRP), cortisol and several immune modulator proteins in the serum of the same individuals and was also positively correlated with CRP, cortisol and pro-inflammatory cytokines in the frontal cortex of the same individuals. In addition, we found a substantial number of nodes (genes) that were common to our schizophrenia-associated immune/inflammation module from the pooled data and a module we generated from lippopolysaccharides-treated mouse model data. These results suggest that the CP of individuals with schizophrenia are responding to signals from the periphery by upregulating immune/inflammation-related genes to protect the brain and maintain the homeostasis but nevertheless fails to completely prevent immune/inflammation related changes in the brain.

The correlation between Toxoplasma gondii infection and prenatal depression in pregnant women

Previous studies have demonstrated that latent toxoplasmosis is associated with neuropsychiatric disorders. We evaluated the correlation between Toxoplasma gondii infection and prenatal depression. In this case-control study, we enrolled 116 depressed pregnant women and 244 healthy controls. The Edinburgh Postpartum Depression Scale (EPDS) was used to evaluate the depression symptom severity in study participants. All participants were screened for the anti-Toxoplasma IgG by enzyme-linked immunosorbent assay. Seroprevalence of T. gondii did not significantly differ between the depressed pregnant women and healthy controls (OR = 1.4; 95 % CI = 0.9-2.19; P = 0.142). T. gondii IgG titer was significantly higher in depressed women (18.6 ± 10.9 IUs) than those in the control group (13.6 ± 8.1 IUs) (z = -5.36, P < 0.001). The T. gondii-positive depressed women showed a positive correlation of T. gondii IgG titer with the EPDS scores (r = 0.52; P < 0.01). The mean EPDS score was also significantly higher in the T. gondii-positive depressed women (20.7 ± 2.7) compared with the controls (18.36 ± 2.7) (P < 0.001). The results obtained from the current study revealed that T. gondii infection might affect susceptibility to depression and severity of depressive symptoms in pregnant women, particularly in those patients who have high antibody titers. Further study is required to fully elucidate the characteristics and mechanisms of this association.

A review of vulnerability and risks for schizophrenia: Beyond the two hit hypothesis

Schizophrenia risk has often been conceptualized using a model which requires two hits in order to generate the clinical phenotype-the first as an early priming in a genetically predisposed individual and the second a likely environmental insult. The aim of this paper was to review the literature and reformulate this binary risk-vulnerability model. We sourced the data for this narrative review from the electronic database PUBMED. Our search terms were not limited by language or date of publication. The development of schizophrenia may be driven by genetic vulnerability interacting with multiple vulnerability factors including lowered prenatal vitamin D exposure, viral infections, smoking intelligence quotient, social cognition cannabis use, social defeat, nutrition and childhood trauma. It is likely that these genetic risks, environmental risks and vulnerability factors are cumulative and interactive with each other and with critical periods of neurodevelopmental vulnerability. The development of schizophrenia is likely to be more complex and nuanced than the binary two hit model originally proposed nearly thirty years ago. Risk appears influenced by a more complex process involving genetic risk interfacing with multiple potentially interacting hits and vulnerability factors occurring at key periods of neurodevelopmental activity, which culminate in the expression of disease state. These risks are common across a number of neuropsychiatric and medical disorders, which might inform common preventive and intervention strategies across non-communicable disorders.

Candida albicans exposures, sex specificity and cognitive deficits in schizophrenia and bipolar disorder

Immune aberrations in schizophrenia and bipolar disorder have led to the hypotheses that infectious agents or corresponding immune responses might contribute to psychiatric etiopathogeneses. We investigated case-control differences in exposure to the opportunistic fungal pathogen, Candida albicans, and examined associations with cognition, medication, lifestyle, and somatic conditions. We quantified C. albicans IgG antibodies in two cohorts totaling 947 individuals and evaluated odds ratios (OR) of exposure with psychiatric disorder using multivariate regressions. The case-control cohort included 261 with schizophrenia, 270 with bipolar disorder, and 277 non-psychiatric controls; the second included 139 with first-episode schizophrenia, 78 of whom were antipsychotic naive. No differences in C. albicans exposures were found until diagnostic groups were stratified by sex. In males, C. albicans seropositivity conferred increased odds for a schizophrenia diagnosis (OR 2.04-9.53, P⩽0.0001). In females, C. albicans seropositivity conferred increased odds for lower cognitive scores on Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) in schizophrenia (OR 1.12, P⩽0.004), with significant decreases on memory modules for both disorders (P⩽0.0007-0.03). C. albicans IgG levels were not impacted by antipsychotic medications. Gastrointestinal (GI) disturbances were associated with elevated C. albicans in males with schizophrenia and females with bipolar disorder (P⩽0.009-0.02). C. albicans exposure was associated with homelessness in bipolar males (P⩽0.0015). In conclusion, sex-specific C. albicans immune responses were evident in psychiatric disorder subsets. Inquiry regarding C. albicans infection or symptoms may expedite amelioration of this treatable comorbid condition. Yeast exposure as a risk factor for schizophrenia and its associated cognitive and GI effects require further investigation including the possible contribution of gut-brain mechanisms.

Too Much Sugar Puts a Parasite in Jeopardy

Toxoplasma gondii and other coccidian parasites accumulate starch-like amylopectin stores whose functional significance is unclear. In this issue of Cell Host & Microbe, Uboldi et al. (2015) present a pioneering investigation into a signaling cascade with a pivotal role in amylopectin metabolism and transmission of encysted parasites during chronic infection.

Shared Immune and Repair Markers During Experimental Toxoplasma Chronic Brain Infection and Schizophrenia

Chronic neurologic infection with Toxoplasma gondii is relatively common in humans and is one of the strongest known risk factors for schizophrenia. Nevertheless, the exact neuropathological mechanisms linking T gondii infection and schizophrenia remain unclear. Here we utilize a mouse model of chronic T gondii infection to identify protein biomarkers that are altered in serum and brain samples at 2 time points during chronic infection. Furthermore, we compare the identified biomarkers to those differing between "postmortem" brain samples from 35 schizophrenia patients and 33 healthy controls. Our findings suggest that T gondii infection causes substantial and widespread immune activation indicative of neural damage and reactive tissue repair in the animal model that partly overlaps with changes observed in the brains of schizophrenia patients. The overlapping changes include increases in C-reactive protein (CRP), interleukin-1 beta (IL-1β), interferon gamma (IFNγ), plasminogen activator inhibitor 1 (PAI-1), tissue inhibitor of metalloproteinases 1 (TIMP-1), and vascular cell adhesion molecule 1 (VCAM-1). Potential roles of these factors in the pathogenesis of schizophrenia and toxoplasmosis are discussed. Identifying a defined set of markers shared within the pathophysiological landscape of these diseases could be a key step towards understanding their specific contributions to pathogenesis.

Surface glycoprotein of Borna disease virus mediates virus spread from cell to cell

Borna disease virus (BDV) is a non-segmented negative-stranded RNA virus that maintains a strictly neurotropic and persistent infection in affected end hosts. The primary target cells for BDV infection are brain cells, e.g. neurons and astrocytes. The exact mechanism of how infection is propagated between these cells and especially the role of the viral glycoprotein (GP) for cell-cell transmission, however, are still incompletely understood. Here, we use different cell culture systems, including rat primary astrocytes and mixed cultures of rat brain cells, to show that BDV primarily spreads through cell-cell contacts. We employ a highly stable and efficient peptidomimetic inhibitor to inhibit the furin-mediated processing of GP and demonstrate that cleaved and fusion-active GP is strictly necessary for the cell-to-cell spread of BDV. Together, our quantitative observations clarify the role of Borna disease virus-glycoprotein for viral dissemination and highlight the regulation of GP expression as a potential mechanism to limit viral spread and maintain persistence. These findings furthermore indicate that targeting host cell proteases might be a promising approach to inhibit viral GP activation and spread of infection.

Seroprevalence of Toxoplasma gondii infection among patients with non-schizophrenic neurodevelopmental disorders in Alexandria, Egypt

Toxoplasma gondii is an opportunistic parasite with neurotropic characteristics that can mediate neurodevelopmental disorders, including mental, behavioral and personality aspects of their hosts. Therefore, the seroprevalence of anti-Toxoplasma antibodies has been studied in patients with different neurological disorders from different localities. On searching online databases, however, we could not find published studies on the seroprevalence of anti-Toxoplasma antibodies among patients with neurodevelopmental disorders in Egypt. Therefore, the present preliminary study was conducted to determine the serological profile of T. gondii infection among patients with non-schizophrenic neurodevelopmental disorders in Alexandria, Egypt. Data and blood samples were collected from 188 patients recruited for the study from four mental rehabilitation centers in the period from July 2014 to March 2015. The overall seropositivity rates of IgM and IgG among patients were 16.5% (31/188) and 50.0% (94/188), respectively. Of the studied patients' characteristics, only age was significantly associated with anti-Toxoplasma IgG seropositivity, with older patients being about twice more likely exposed to infection. However, no statistically significant association was found with IgM. In addition, seropositivity of anti-Toxoplasma IgG, but not IgM, was significantly associated with non-schizophrenic neurodevelopmental disorders; however, neither IgG nor IgM showed a significant association with cognitive impairment as indicated by the intelligence quotient scores.

Chlamydia pneumoniae Infection and Inflammatory Diseases

Chlamydia pneumoniae, an obligate intracellular bacterial pathogen, has long been investigated as a potential developmental or exacerbating factor in various pathologies. Its unique lifestyle and ability to disseminate throughout the host while persisting in relative safety from the immune response has placed this obligate intracellular pathogen in the crosshairs as a potentially mitigating factor in chronic inflammatory diseases. Many animal model and human correlative studies have been performed to confirm or deny a role for C. pneumoniae infection in these disorders. In some cases, antibiotic clinical trials were conducted to prove a link between bacterial infections and atherosclerosis. In this review, we detail the latest information regarding the potential role that C. pneumoniae infection may have in chronic inflammatory diseases.

Mortality in schizophrenia and bipolar disorder: Clinical and serological predictors

Persons with schizophrenia and with bipolar disorder have a reduced life expectancy due largely to death from natural causes. The reasons for this increased mortality have not been completely defined. We prospectively assessed a cohort of persons with schizophrenia and one with bipolar disorder with a clinical evaluation and a blood sample from which immune and infectious disease markers were measured. Mortality was determined with data from the National Death Index following a period of up to 14years. We examined the role of demographic, clinical, and serological factors on mortality in bivariate and multivariate models. A total of 43/710 (6.1%) persons with schizophrenia and 12/406 (3.0%) with bipolar disorder died of natural causes. In the schizophrenia group, mortality was predicted by the following variables in a multivariate model: cigarette smoking (RR=6.93, 95% CI 1.59, 30.1, p=0.0099); autoimmune disorder (RR=8.08, 95% CI 2.50, 26.1, p=0.00047); gastrointestinal disorder (GI) (RR=3.53, 95% CI 1.43, 8.69 p=0.0061); and reduced maternal education (RR=0.84, 95% CI 0.72, 0.97), p=0.018. The combination of smoking and an autoimmune disorder yielded an unadjusted relative risk of 18.1 for mortality, and the combination of smoking and a GI disorder an unadjusted relative risk of 9.45, compared with individuals with neither risk factor. In the bipolar disorder group, significant bivariate predictors of mortality included lower cognitive score (RR=0.95, p=.0085) and the presence of type 1 or 2 diabetes (RR=3.90, p=.026). Given the extraordinary high risk of death due to smoking in schizophrenia, smoking cessation remains an urgent priority.

Role of Immune and Autoimmune Dysfunction in Schizophrenia

In this chapter, we review data in support of the concept that immune system dysregulation is the most plausible explanation that reconciles gene by environmental interactions in schizophrenia. Early investigations of this topic demonstrated aspects of aberrant activation of humoral immunity, including autoimmunity, associated with schizophrenia, whereas current research efforts have expanded this theme to include elements of innate immunity. Advances in our understanding of inflammation and molecules of both the adaptive and innate immune system and their functional roles in standard brain physiology provide an important context by which schizophrenia might arise as the result of the coupling of immune and neurodevelopmental dysregulation.

The association between antibodies to neurotropic pathogens and schizophrenia: a case-control study

Background:

Exposure to neurotropic pathogens has been proposed as an environmental risk factor for schizophrenia and can be evaluated by measuring pathogen-specific immunoglobulin G (IgG). Seroprevalence of pathogen-specific IgG reflects prior exposure, whereas IgG levels are associated with reactivity or reinfection. Several studies have examined these parameters in schizophrenia. However, results still remain inconclusive, as several previous studies did not correct for important confounding factors.

Aims:

To investigate whether schizophrenia is associated with prior exposure to neurotropic pathogens, or with their reactivation.

Methods:

We examined the seroprevalence and titer of IgG antibodies against herpes simplex virus-1 and -2 (HSV-1/HSV-2), varicella zoster virus (VZV), Epstein–Barr virus (EBV), cytomegalovirus (CMV), and Toxoplasma gondii (TG) in plasma of 368 adult patients with a schizophrenia spectrum disorder and 282 controls using ELISA.

Results:

We did not find evidence for an increased exposure to HSV-1, HSV-2, EBV, and TG in patients. There was a significantly higher seroprevalence of VZV (98.9% vs. 95.6%, P<0.05) and CMV (40.4% vs. 27.7%, P<0.001) in controls as compared with patients, which did not remain statistically significant after adjustment for various potential confounders. We did not find significant differences in antibody titers of seropositive patients and controls for any of the six pathogens.

Conclusions:

Our results do not support the hypothesis that increased exposure to neurotropic pathogens after birth is associated with schizophrenia.

Viral metagenomics in drug-naïve, first-onset schizophrenia patients with prominent negative symptoms

Although several studies suggest a virus or (endogenous) retrovirus involvement at the time of onset of schizophrenia, the unequivocal identification of one or more infectious agents, by means of an undirected catch-all technique, has never been conducted. In this study VIDISCA, a virus discovery method, was used in combination with Roche-454 high-throughput sequencing as a tool to determine the possible presence of viruses (known or unknown) in blood of first-onset drugs-naïve schizophrenic patients with prominent negative symptoms. Two viruses (the Anellovirus Torque Teno virus and GB virus C) were detected. Both viruses are commonly found in healthy individuals and no clear link with disease was ever established. Viruses from the family Anelloviridae were also identified in the control population (4.8%). Besides, one patient sample was positive for human endogenous retroviruses type K (HML-2) RNA but no specific predominant strain was detected, instead 119 different variants were found. In conclusion, these findings indicate no evidence for viral or endogenous retroviral involvement in sera at the time of onset of schizophrenia.

New discoveries in schizophrenia genetics reveal neurobiological pathways: A review of recent findings

Schizophrenia research has undergone a recent transformation. By leveraging large sample sizes, genome-wide association studies of common genetic variants have approximately tripled the number of candidate genetic loci. Rare variant studies have identified copy number variants that are schizophrenia risk loci. Among these, the 3q29 microdeletion is now known to be the single largest schizophrenia risk factor. Next-generation sequencing studies are increasingly used for rare variant association testing, and have already facilitated identification of large effect alleles. Collectively, recent findings implicate voltage-gated calcium channel and cytoskeletal pathways in the pathogenesis of schizophrenia. Taken together, these results suggest the possibility of imminent breakthroughs in the molecular understanding of schizophrenia.

Assessing brain immune activation in psychiatric disorders: clinical and preclinical PET imaging studies of the 18-kDa translocator protein

Accumulating evidence from different lines of research suggests an involvement of the immune system in the pathophysiology of several psychiatric disorders. During recent years, a series of positron emission tomography (PET) studies have been published using radioligands for the translocator protein (TSPO) to study microglia activation in schizophrenia, bipolar I disorder, major depression, autism spectrum disorder, and drug abuse. The results have been somewhat conflicting, which could be due to differences both in patient sample characteristics and in PET methods. In particular, further work is needed to address both methodological and biological sources of variability in TSPO levels, a process in which the use of animal models and small animal PET systems can be a valuable tool. Given this development, PET studies of immune activation have the potential to further increase our understanding of disease mechanisms in psychiatric disorders, which is a requisite in the search for new treatment approaches. Furthermore, molecular imaging could become an important clinical tool for identifying specific subgroups of patients or disease stages that would benefit from treatment targeting the immune system.

Beyond the association. Toxoplasma gondii in schizophrenia, bipolar disorder, and addiction: systematic review and meta-analysis

OBJECTIVE

To perform a meta-analysis on studies reporting prevalence of Toxoplasma gondii (T. gondii) infection in any psychiatric disorder compared with healthy controls. Our secondary objective was to analyze factors possibly moderating heterogeneity.

METHOD

A systematic search was performed to identify studies into T. gondii infection for all major psychiatric disorders versus healthy controls. Methodological quality, publication bias, and possible moderators were assessed.

RESULTS

A total of 2866 citations were retrieved and 50 studies finally included. Significant odds ratios (ORs) with IgG antibodies were found in schizophrenia (OR 1.81, P < 0.00001), bipolar disorder (OR 1.52, P = 0.02), obsessive-compulsive disorder (OR 3.4, P < 0.001), and addiction (OR 1.91, P < 0.00001), but not for major depression (OR 1.21, P = 0.28). Exploration of the association between T. gondii and schizophrenia yielded a significant effect of seropositivity before onset and serointensity, but not IgM antibodies or gender. The amplitude of the OR was influenced by region and general seroprevalence. Moderators together accounted for 56% of the observed variance in study effects. After controlling for publication bias, the adjusted OR (1.43) in schizophrenia remained significant.

CONCLUSION

These findings suggest that T. gondii infection is associated with several psychiatric disorders and that in schizophrenia reactivation of latent T. gondii infection may occur.

Cognitive deterioration among bipolar disorder patients infected by Toxoplasma gondii is correlated to interleukin 6 levels

BACKGROUND

Cognitive deficits are present in a large majority of Bipolar Disorder (BD) patients and known to be a marker of bad prognosis. Because, these deficits encompass several domains and no specific medical treatment seems to be effective, it is important to better understand the mechanisms underlying cognitive deterioration. As Toxoplasma gondii is known to induce the synthesis of pro-inflammatory cytokines such as IL-6, we will explore here the possible role of T. gondii in the cognitive decline observed in BD.

METHODS

42 euthymic BD patients and 36 controls were assessed for episodic verbal memory using the CVLT and for working memory and verbal ability using the WAIS III. Patients and controls were also screened for seropositivity to T. gondii and evaluated for the levels of IL-6 transcripts.

RESULTS

The seropositivity for T. gondii was significantly higher in BD patients as compared to controls (p=0.005). The cognitive deterioration index (DI) was higher in BD patients (p=5.10(-6)) and correlated to high IL-6 mRNA expression only among those infected by T. gondii (rho=0.43, p=0.01). Among deteriorated patients (defined by scores above 0.10 according to Weschler׳s definition), the IL-6 mRNA expression was twice greater (p=0.01).

LIMITATIONS

Our results are to be interpreted with caution because of our small sample size and the cross-sectional design.

CONCLUSIONS

A long-term exposure to inflammation, measured here with IL-6 mRNA expression in T. gondii infected BD may alter cognitive functioning. IL-6 could thus be a useful predictive marker of cognitive deterioration in BD and may help to design personalized treatment.

Chronic Toxoplasma gondii in Nurr1-null heterozygous mice exacerbates elevated open field activity

Latent infection with Toxoplasma gondii is common in humans (approximately 30% of the global population) and is a significant risk factor for schizophrenia. Since prevalence of T. gondii infection is far greater than prevalence of schizophrenia (0.5-1%), genetic risk factors are likely also necessary to contribute to schizophrenia. To test this concept in an animal model, Nurr1-null heterozygous (+/-) mice and wild-type (+/+) mice were evaluate using an emergence test, activity in an open field and with a novel object, response to bobcat urine and prepulse inhibition of the acoustic startle response (PPI) prior to and 6 weeks after infection with T. gondii. In the emergence test, T. gondii infection significantly decreased the amount of time spent in the cylinder. Toxoplasma gondii infection significantly elevated open field activity in both +/+ and +/- mice but this increase was significantly exacerbated in +/- mice. T. gondii infection reduced PPI in male +/- mice but this was not statistically significant. Aversion to bobcat urine was abolished by T. gondii infection in +/+ mice. In female +/- mice, aversion to bobcat urine remained after T. gondii infection while the male +/- mice showed no aversion to bobcat urine. Antibody titers of infected mice were a critical variable associated with changes in open field activity, such that an inverted U shaped relationship existed between antibody titers and the percent change in open field activity with a significant increase in activity at low and medium antibody titers but no effect at high antibody titers. These data demonstrate that the Nurr1 +/- genotype predisposes mice to T. gondii-induced alterations in behaviors that involve dopamine neurotransmission and are associated with symptoms of schizophrenia. We propose that these alterations in murine behavior were due to further exacerbation of the altered dopamine neurotransmission in Nurr1 +/- mice.

Treatment with anti-toxoplasmic activity (TATA) for toxoplasma positive patients with bipolar disorders or schizophrenia: a cross-sectional study

OBJECTIVE

The association between Toxoplasma gondii seropositivity and respectively Bipolar Disorder (BD) and Schizophrenia/Schizoaffective disorder (SZ) is one of the most studied link between one pathogen and psychiatric disorders. The aim of the present study was thus to retrospectively determine if the administration of an antipsychotic and/or a mood stabilizer having known in vitro Anti-Toxoplasmic Activity (TATA+) was associated with a better clinical outcome in a population of 152 BD or 114 SZ patients and seropositive for T. gondii infection compared to patients receiving a treatment without anti-toxoplasmic activity (TATA-).

METHODS

This multicenter study was conducted in an academic public hospital during a 3-years period between 2009 and 2011. All consecutive inpatients and outpatients with SZ or BD diagnosis with a stable treatment for more than 4 weeks were recruited. socio-demographic and clinical characteristics measured with validated scales as well as a serological status for toxoplasmic infection were included. Treatments were classified according to their in vitro antitoxoplasmic activity. A multivariate model was used to determine the clinical characteristics that were significantly different between patients receiving a treatment with no antitoxoplasmic activity compared to others.

RESULTS

BD patients with positive serum antibodies against T. gondii presented more lifetime depressive episodes (p = 0.048) after adjustment for age, sex and sociodemographic characteristics when treated by drug having no anti-toxo activity, compared to patients having received drugs with anti-toxo activity. A significant difference was not found in BD toxonegative patients and in SZ toxopositive or toxonegative patients.

CONCLUSIONS

It seems to be of importance to consider prescribing a drug with a clear anti-toxoplasmic activity (TATA+) for BD patients seropositive to T. gondii, in particular valproate that was found as the mood stabilizer with the highest antitoxoplasmic activity. Prospective randomized controlled trials are warranted to confirm this preliminary data.

Infection and inflammation in schizophrenia and bipolar disorder: a genome wide study for interactions with genetic variation

Inflammation and maternal or fetal infections have been suggested as risk factors for schizophrenia (SZ) and bipolar disorder (BP). It is likely that such environmental effects are contingent on genetic background. Here, in a genome-wide approach, we test the hypothesis that such exposures increase the risk for SZ and BP and that the increase is dependent on genetic variants. We use genome-wide genotype data, plasma IgG antibody measurements against Toxoplasma gondii, Herpes simplex virus type 1, Cytomegalovirus, Human Herpes Virus 6 and the food antigen gliadin as well as measurements of C-reactive protein (CRP), a peripheral marker of inflammation. The subjects are SZ cases, BP cases, parents of cases and screened controls. We look for higher levels of our immunity/infection variables and interactions between them and common genetic variation genome-wide. We find many of the antibody measurements higher in both disorders. While individual tests do not withstand correction for multiple comparisons, the number of nominally significant tests and the comparisons showing the expected direction are in significant excess (permutation p=0.019 and 0.004 respectively). We also find CRP levels highly elevated in SZ, BP and the mothers of BP cases, in agreement with existing literature, but possibly confounded by our inability to correct for smoking or body mass index. In our genome-wide interaction analysis no signal reached genome-wide significance, yet many plausible candidate genes emerged. In a hypothesis driven test, we found multiple interactions among SZ-associated SNPs in the HLA region on chromosome 6 and replicated an interaction between CMV infection and genotypes near the CTNNA3 gene reported by a recent GWAS. Our results support that inflammatory processes and infection may modify the risk for psychosis and suggest that the genotype at SZ-associated HLA loci modifies the effect of these variables on the risk to develop SZ.

Behavioral alterations in rat offspring following maternal immune activation and ELR-CXC chemokine receptor antagonism during pregnancy: implications for neurodevelopmental psychiatric disorders

Research suggests that maternal immune activation (MIA) during pregnancy increases the risk of neurodevelopmental disorders including schizophrenia and autism in the offspring. Current theories suggest that inflammatory mediators including cytokines and chemokines may underlie the increased risk of these disorders in humans. For example, elevated maternal interleukin-8 (IL-8) during pregnancy is associated with increased risk of schizophrenia in the offspring. Given this association, the present experiments examined ELR-CXC chemokines CXCL1 and CXCL2, rodent homologues of human IL-8, and activation of their receptors (CXCR1 and CXCR2) in an established rodent model of MIA. Pregnant Long Evans rats were treated with the viral mimetic polyinosinic-polycytidylic acid (polyI:C; 4 mg/kg, i.v.) on gestational day 15. Protein analysis using multiplex assays and ELISA showed that polyI:C significantly increased maternal serum concentrations of interleukin-1β, tumor necrosis factor, and CXCL1 3h after administration. Subsequent experiments tested the role of elevated maternal CXCL1 on behavior of the offspring by administering a CXCR1/CXCR2 antagonist (G31P; 500 μg/kg, i.p.; 1h before, 48 and 96 h after polyI:C treatment). The male offspring of dams treated with polyI:C demonstrated subtle impairments in prepulse inhibition (PPI), impaired associative and crossmodal recognition memory, and altered behavioral flexibility in an operant test battery. While G31P did not completely reverse the behavioral impairments caused by polyI:C, it enhanced PPI during adolescence and strategy set-shifting and reversal learning during young adulthood. These results suggest that while polyI:C treatment significantly increases maternal CXCL1, elevations of this chemokine are not solely responsible for the effects of polyI:C on the behavior of the offspring.

Somatic diseases and conditions before the first diagnosis of schizophrenia: a nationwide population-based cohort study in more than 900 000 individuals

OBJECTIVE

Schizophrenia is associated with excess physical comorbidity. Yet, to our knowledge, large studies are lacking on the associations with somatic diseases before the onset of schizophrenia. The authors conducted a nationwide study of the full spectrum of treated somatic diseases before the first diagnosis of schizophrenia.

METHOD

Nationwide sample of the Danish population consisting of singletons (n = 954351) born 1977-1993 and followed from birth to 2009, during which period 4371 developed schizophrenia. Somatic diagnoses at all general hospital contacts (admitted or outpatient care at a somatic hospital) from 1977 to 2009 were used as exposures. The incidence rate ratio (IRR) of schizophrenia was calculated using Poisson regression adjusted for confounders.

RESULTS

Among the 4371 persons who developed schizophrenia from 1992 to 2009, a total of 4180 (95.6%) persons had a previous somatic hospital contact. A history of any somatic hospital contact was associated with an elevated risk of schizophrenia (IRR = 2.04, 95% CI = 1.77-2.37). A wide range of somatic diseases and conditions were associated with an increased risk of schizophrenia, including epilepsy (IRR = 2.26, 95% CI = 1.93-2.62), nutritional or metabolic disorders (IRR = 1.57, 95% CI = 1.39-1.77), circulatory system diseases (IRR = 1.63, 95% CI= 1.38-1.92), and brain injury (IRR = 1.58, 95% CI = 1.45-1.72).

CONCLUSIONS

A wide range of potential etiological factors could have contributed to the observed associations, including genetic or physiological overlaps between conditions, and interacting immunological, behavioral, and neurodevelopmental factors.

Improvement in psychotic symptoms after a gluten-free diet in a boy with complex autoimmune illness

At age 8, “Chris,” a Caucasian boy, experienced intermittent auditory and visual hallucinations, but without bizarre behaviors or much deterioration in functioning. At age 15, he developed a depressed mood, started talking to himself, and became socially withdrawn, and his academic performance declined. He was hospitalized and diagnosed as having major depressive disorder with psychotic features. MRI and EEG showed no abnormalities. Treatment with escitalopram (10 mg/day) and aripiprazole (5 mg/day) had little effect. Several weeks after discharge, he was admitted for a second time with the same diagnosis; a third admission, again with the same diagnosis, occurred several months after that. At age 16, Chris developed visual and auditory hallucinations with homicidal ideations. He cut himself superficially following the command of voice hallucinations, and he was hospitalized again, with the diagnosis changed to schizophrenia, paranoid type. During this inpatient stay, he was treated with venlafaxine (150 mg/day) and risperidone (1.5 mg/day). During the same admission, a blood test showed the presence of antinuclear antibodies (ANAs), but the patient had no symptoms of any autoimmune disease. In the meantime, he was also receiving clindamycin/benzoyl peroxide and adapaline gels and minocycline for acne and fluticasone nasal spray and albuterol for asthma. An allergy to gluten was demonstrated by an assay (Accessa Labs) that showed only IgE antigluten antibodies. Chris’sparents reported that he developed anallergy to peanuts and soy at about the same time. Gluten was removed from his diet at the suggestion of the mother, a licensed dietitian. After the dietary change, the intensity of Chris’s auditory hallucinations declined dramatically and the violent element diminished, and he was discharged after 9 weeks. During the next 2 years, Chris remained on a gluten-free diet, which he and his family associated with the disappearance of his psychotic symptoms. Sensitivity to gluten was demonstrated by an assay (Metametrix Clinical Laboratory) of a stool sample that yielded a value of 10.6 mg/dL of IgA antigliadin antibodies, in the top quintile of the reference range. The dosage of risperidone was tapered to 0.5 mg/day, and no auditory or visual hallucinations occurred, although when the dosage was lowered to 0.25 mg/day, Chris reported feeling anxious, and the dosage was returned to 0.5 mg/day for a time. Eventually the risperidone was discontinued completely. Chris was able to return to school, where his academic performance was normal and he joined several athletic teams. At age 16, after his hospital stay, Chris lost his hearing suddenly and was fitted with a hearing aid. His ANA level was high, and the diagnosis of autoimmune inner ear disease was made. He was treated with prednisone and then methotrexate over a 2-month period. Despite his hearing loss, he has maintained a high level of functioning, including learning to read lips, and he has continued to play competitive sports. Both of Chris’s parents have a history of seasonal affective disorder, and two grandparents had experienced bouts of depression. The father had hypothyroidism, and the father’s aunt had Crohn’s disease. The mother’s brother had hearing loss with ANAs, and the mother’s cousin had systemic lupus erythematosus. The parents were 32 years old when Chris was born, and the pregnancy and birth were unremarkable, with no complications. He is the second son. Starting in infancy, he had recurrent bouts of otitis media, which were treated with tympanoplasty and continued until age 12. At 3 months, he was diagnosed with eosinophilic gastritis.

Seropositivity and serointensity of Toxoplasma gondii antibodies and DNA among patients with schizophrenia

The aim of this cross sectional case control study was to examine the serofrequency and serointensity of Toxoplasma gondii (Tg) IgG, IgM, and DNA among patients with schizophrenia. A total of 101 patients with schizophrenia and 55 healthy controls from Sungai Buloh Hospital, Selangor, Malaysia and University Malaya Medical Center (UMMC) were included in this study. The diagnosis of schizophrenia was made based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). The presence of Tg infection was examined using both indirect (ELISA) and direct (quantitative real-time PCR) detection methods by measuring Tg IgG and IgM and DNA, respectively. The serofrequency of Tg IgG antibodies (51.5%, 52/101) and DNA (32.67%, 33/101) among patients with schizophrenia was significantly higher than IgG (18.2%, 10/55) and DNA (3.64%, 2/55) of the controls (IgG, P=0.000, OD=4.8, CI=2.2-10.5; DNA, P=0.000, OD=12.9, CI=2.17-10.51). However, the Tg IgM antibody between patients with schizophrenia and controls was not significant (P>0.005). There was no significant difference (P>0.005) in both serointensity of Tg IgG and DNA between patients with schizophrenia and controls. These findings have further demonstrated the strong association between the active Tg infection and schizophrenia.

Genetic pleiotropy between multiple sclerosis and schizophrenia but not bipolar disorder: differential involvement of immune-related gene loci

Converging evidence implicates immune abnormalities in schizophrenia (SCZ), and recent genome-wide association studies (GWAS) have identified immune-related single-nucleotide polymorphisms (SNPs) associated with SCZ. Using the conditional false discovery rate (FDR) approach, we evaluated pleiotropy in SNPs associated with SCZ (n=21,856) and multiple sclerosis (MS) (n=43,879), an inflammatory, demyelinating disease of the central nervous system. Because SCZ and bipolar disorder (BD) show substantial clinical and genetic overlap, we also investigated pleiotropy between BD (n=16,731) and MS. We found significant genetic overlap between SCZ and MS and identified 21 independent loci associated with SCZ, conditioned on association with MS. This enrichment was driven by the major histocompatibility complex (MHC). Importantly, we detected the involvement of the same human leukocyte antigen (HLA) alleles in both SCZ and MS, but with an opposite directionality of effect of associated HLA alleles (that is, MS risk alleles were associated with decreased SCZ risk). In contrast, we found no genetic overlap between BD and MS. Considered together, our findings demonstrate genetic pleiotropy between SCZ and MS and suggest that the MHC signals may differentiate SCZ from BD susceptibility.

Different presence of Chlamydia pneumoniae, herpes simplex virus type 1, human herpes virus 6, and Toxoplasma gondii in schizophrenia: meta-analysis and analytical study

In the present study we have performed both a meta-analysis and an analytical study exploring the presence of Chlamydia pneumoniae, herpes simplex virus type 1, human herpes virus 6, and Toxoplasma gondii antibodies in a sample of 143 schizophrenic patients and 143 control subjects. The meta-analysis was performed on papers published up to April 2014. The presence of serum immunoglobulin G and immunoglobulin A was performed by enzyme-linked immunosorbent assay test. The detection of microbial DNA in total peripheral blood was performed by nested polymerase chain reaction. The meta-analysis showed that: 1) C. pneumoniae DNA in blood and brain are more common in schizophrenic patients; 2) there is association with parasitism by T. gondii, despite the existence of publication bias; and 3) herpes viruses were not more common in schizophrenic patients. In our sample only anti-Toxoplasma immunoglobulin G was more prevalent and may be a risk factor related to schizophrenia, with potential value for prevention.

The Role of Infections and Autoimmune Diseases for Schizophrenia and Depression: Findings from Large-Scale Epidemiological Studies

An immunologic component to schizophrenia and depression has been increasingly recognized, which has led to extensive research into the associations with infections and autoimmune diseases. Large-scale nationwide epidemiological studies have displayed an increased prevalence of both autoimmune diseases and infections among persons with schizophrenia and depression. Autoimmune diseases, and especially the number of infections requiring hospitalization, increase the risk of schizophrenia and depression in a dose–response relationship. Infections are a common exposure and a broad spectrum of infections are associated with schizophrenia and depression. Particularly the autoimmune diseases with a potential presence of brain-reactive antibodies were associated with psychiatric disorders. However, the associations seem to be bidirectional, since the risk of autoimmune diseases and infections is also increased after diagnosis with schizophrenia and depression. The risk of autoimmune diseases was particularly increased in individuals with prior hospital contacts for infections.

It has been suggested that inflammation and autoimmunity could be involved in the etiology and pathogenesis of some patients with symptoms of schizophrenia and depression. The psychiatric symptoms can be directly triggered by immune components, such as brain-reactive antibodies and cytokines, or infections reaching the central nervous system (CNS), or be secondary to systemic inflammation indirectly affecting the brain. However, the associations could also be caused by shared genetic factors, other environmental factors, or common etiological components. Nonetheless, autoimmune diseases and infections should be considered by clinicians in the treatment of individuals with psychiatric symptoms, since treatment would probably improve the psychiatric symptoms, quality of life, and the survival of the individuals.

[Parvovirus B19 seroprevalence in a group of schizophrenic patients]

BACKGROUND

Schizophrenia is a highly disabling chronic mental illness. It is considerded as a neurodeveloppemental illness resulting from the interaction of genetic and environmental factors. Growing evidence supports the major role of prenatal infections and inflammation in the genesis of schizophrenia. The hypothesis including viral infections has been the subject of several studies and the role of parvovirus B19 (PB19) in the onset of the disease has been suggested. However, there is, up till now, no seroepidemiological evidence of his involvement.

OBJECTIVE

To determine the prevalence of parvovirus B19 (PB19) in schizophrenic patients and in control subjects and to examine clinical associations between viral prevalence, risk factors of infectious disease and clinical features.

METHOD

We carried out a case-control seroepidemiological study in the Psychiatry department of Farhat-Hached general hospital of Sousse (Tunisia). We recruited108 schizophrenic patients and 108 healthy controls free from any psychotic disorder and matched for age and sex. We collected sociodemographic data, medical history, axis I comorbid disorders and infectious risk factors. We assessed patients for psychopathology and severity of illness using respectively the Brief Psychiatric Rating Scale (BPRS), the Scale for the Assessment of Positive Symptoms (SAPS), the Scale for the Assessment of Negative Symptoms (SANS), the Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impressions (CGI). For each study participant, blood sample was collected and levels of IgG and IgM anti-PB19 were measured using the ELISA technique.

RESULTS

The prevalence of IgG antibodies to PB19 was significantly higher in schizophrenic patients than in controls (73.1% vs 60.2%; P=0.04). There were no statistical differences between the two groups regarding the prevalence of IgM antibodies to PB19. No association was found between viral prevalence and sociodemographic data, risk factors for infection or clinical characteristics. The presence of PB19 antibodies was associated with a lower score on the PANSS negative subscale (P=0.04). No other signficative association were found.

CONCLUSIONS

In our study, prevalence of IgG antibodies to PB19 was significantly higher in schizophrenic patients than in controls. This finding supports the hypothesis of the involvement of PB19 in schizophrenia. Further studies including both virological and immunological aspects are needed to better clarify the etiopathogenic mechanisms of schizophrenia which would challenge the management of this disease.

Heritability of Transforming Growth Factor-β1 and Tumor Necrosis Factor-Receptor Type 1 Expression and Vitamin D Levels in Healthy Adolescent Twins

Cytokines and vitamin D both have a role in modulating the immune system, and are also potentially useful biomarkers in mental illnesses such as major depressive disorder (MDD) and schizophrenia. Studying the variability of cytokines and vitamin D in a healthy population sample may add to understanding the association between these biomarkers and mental illness. To assess genetic and environmental contributions to variation in circulating levels of cytokines and vitamin D (25-hydroxy vitamin D: 25(OH)D3), we analyzed data from a healthy adolescent twin cohort (mean age 16.2 years; standard deviation 0.25). Plasma cytokine measures were available for 400 individuals (85 MZ, 115 DZ pairs), dried blood spot sample vitamin D measures were available for 378 individuals (70 MZ, 118 DZ pairs). Heritability estimates were moderate but significant for the cytokines transforming growth factor-β1 (TGF-β1), 0.57 (95% CI 0.26–0.80) and tumor necrosis factor-receptor type 1 (TNFR1), 0.50 (95% CI 0.11–0.63) respectively. Measures of 25(OH)D3 were within normal range and heritability was estimated to be high (0.86, 95% CI 0.61–0.94). Assays of other cytokines did not generate meaningful results. These potential biomarkers may be useful in mental illness, with further research warranted in larger sample sizes. They may be particularly important in adolescents with mental illness where diagnostic uncertainty poses a significant clinical challenge.

How much do we know about schizophrenia and how well do we know it? Evidence from the Schizophrenia Library

BACKGROUND

True findings about schizophrenia remain elusive; many findings are not replicated and conflicting results are common. Well-conducted systematic reviews have the ability to make robust, generalizable conclusions, with good meta-analyses potentially providing the closest estimate of the true effect size. In this paper, we undertake a systematic approach to synthesising the available evidence from well-conducted systematic reviews on schizophrenia.

METHOD

Reviews were identified by searching Medline, EMBASE, CINAHL, Current Contents and PsycINFO. The decision to include or exclude reviews, data extraction and quality assessments were conducted in duplicate. Evidence was graded as high quality if reviews contained large samples and robust results; and as moderate quality if reviews contained imprecision, inconsistency, smaller samples or study designs that may be prone to bias.

RESULTS

High- and moderate-quality evidence shows that numerous psychosocial and biomedical treatments are effective. Patients have relatively poor cognitive functioning, and subtle, but diverse, structural brain alterations, altered electrophysiological functioning and sleep patterns, minor physical anomalies, neurological soft signs, and sensory alterations. There are markers of infection, inflammation or altered immunological parameters; and there is increased mortality from a range of causes. Risk for schizophrenia is increased with cannabis use, pregnancy and birth complications, prenatal exposure to Toxoplasma gondii, childhood central nervous system viral infections, childhood adversities, urbanicity and immigration (first and second generation), particularly in certain ethnic groups. Developmental motor delays and lower intelligence quotient in childhood and adolescence are apparent.

CONCLUSIONS

We conclude that while our knowledge of schizophrenia is very substantial, our understanding of it remains limited.

An expanded task battery in the Morris water maze reveals effects of Toxoplasma gondii infection on learning and memory in rats

Infection with the neurotropic parasite Toxoplasma gondii is widespread among human populations; however, the impacts of latent central nervous system (CNS) T. gondii infection have only recently come to light. Epidemiological evidence in humans and experimental studies in rodents have revealed a number of neurological and behavioral sequelae following the establishment of latent CNS toxoplasmosis. Here, we report alterations in learning and memory task performance in latently infected rats using the Morris water maze. While simple spatial reference learning was intact, infected rodents exhibited poor performance compared to controls in probe trials requiring spatial memory recall and progressively poorer performance with increasing time intervals before memory testing, but, surprisingly, enhanced performance in reversal learning tasks. Despite obvious changes to memory task performance, no cysts were detected in the hippocampi of infected rats. Instead, cysts were stochastically distributed across the entire brain, suggesting that behavioral alterations in this study were due to accumulated changes in neurophysiology across multiple anatomical regions. Together, these data provide new evidence that latent toxoplasmosis contributes to neurocognitive symptoms in mammalian hosts, and does so on a broad anatomical scale within the CNS.

Inflammatory molecular signature associated with infectious agents in psychosis

Schizophrenia (SZ) is a devastating mental condition with onset in young adulthood. The identification of molecular biomarkers that reflect illness pathology is crucial. Recent evidence suggested immune and inflammatory cascades in conjunction with infection may play a role in the pathology. To address this question, we investigated molecular changes in cerebrospinal fluid (CSF) from antipsychotic-naïve patients with SZ and at risk mental status for psychosis (ARMS), in comparison with healthy controls (HCs). We measured 90 analytes using a broad multiplex platform focusing on immune and inflammatory cascades then selected 35 with our quality reporting criteria for further analysis. We also examined Toxoplasma gondii (TG) and herpes simplex virus 1 antibody levels in CSF. We report that expression of 15 molecules was significantly altered in the patient groups (SZ and ARMS) compared with HCs. The majority of these molecular changes (alpha-2-macroglobulin [α2M], fibrinogen, interleukin-6 receptor [IL-6R], stem cell factor [SCF], transforming growth factor alpha [TGFα], tumor necrosis factor receptor 2 [TNFR2], IL-8, monocyte chemotactic protein 2 [MCP-2/CCL8], testosterone [for males], angiotensin converting enzyme [ACE], and epidermal growth factor receptor) were consistent between SZ and ARMS patients, suggesting these may represent trait changes associated with psychotic conditions in general. Interestingly, many of these analytes (α2M, fibrinogen, IL-6R, SCF, TGFα, TNFR2, IL-8, MCP-2/CCL8, and testosterone [for males]) were exacerbated in subjects with ARMS compared with subjects with SZ. Although further studies are needed, we optimistically propose that these molecules may be good candidates for predictive markers for psychosis from an early stage. Lastly, reduction of IL-6R, TGFα, and ACE was correlated with positivity of TG antibody in the CSF, suggesting possible involvement of TG infection in the pathology.

Congenital Toxoplasmosis

Toxoplasmosis is caused by infection with the parasite Toxoplasma gondii. It is one of the most common parasitic infections in humans and is most typically asymptomatic. However, primary infection in a pregnant woman can cause severe and disabling disease in the developing fetus. Recent developments have included increased understanding of the role of parasite genotype in determining infectivity and disease severity. Risk factors for acquisition of infection have been better defined, and the important role of foodborne transmission has been further delineated. In addition, strategies have emerged to decrease mother-to-child transmission through prompt identification of acutely infected pregnant women followed by appropriate treatment. Refined diagnostic tools, particularly the addition of immunoglobulin G avidity testing, allow for more accurate timing of maternal infection and hence better decision making during pregnancy. Congenitally infected children can be treated, beginning in utero and continuing through the first year of life, to ameliorate the severity of disease. However, despite these many advances in our understanding of congenital toxoplasmosis prevention and treatment, significant areas of study remain: we need better drugs, well defined strategies for screening of pregnant women, improved food safety, and improved diagnostic tests.

Mortality in schizophrenia: clinical and serological predictors

Persons with schizophrenia have a reduced life expectancy largely due to death from natural causes. Factors that have been previously associated with excess mortality include cigarette smoking and antipsychotic medication. The role of other environmental factors such as exposure to infectious agents has been the subject of only limited investigation. We prospectively assessed a cohort of persons with schizophrenia with a clinical evaluation and a blood sample from which antibodies to human herpes viruses and Toxoplasma gondii were measured. Mortality was determined with data from the National Death Index following a period of up to 11 years. We examined the role of demographic, serological, and clinical factors on mortality. A total of 25 (5%) of 517 persons died of natural causes. The standardized mortality ratio was 2.80 (95% CI 0.89, 6.38). After adjusting for age and gender, mortality from natural causes was predicted in separate models by cigarette smoking (relative risk [RR] = 4.66, P = .0029); lower cognitive score (RR = 0.96, P = .013); level of antibodies to Epstein-Barr virus (RR = 1.22, P = .0041) and to Herpes Simplex virus type 1 (RR = 1.19, P = .030); immunologic disease (RR = 3.14, P = .044); and genitourinary disease (RR = 2.70; P = .035). Because cigarette smoking confers an almost 5-fold risk of mortality, smoking cessation is an urgent priority. Having an elevated level of antibodies to Epstein-Barr virus and to Herpes Simplex virus type 1 are also significant predictors of death from natural causes.

Different rates of first admissions for psychosis in migrant groups in Paris

PURPOSE

The association between migration and psychosis has been reported in the past decades in many European countries. Despite large-scale migration into France, epidemiological data on the incidence of psychosis in this population are lacking. In this study, we compare the incidence rates of first admission for psychosis among natives and first generation migrants.

METHODS

Two-hundred and fifty-eight patients aged 15+ with first admission for psychosis were identified in the catchment area of the 20th district of Paris between 2005 and 2009. Standardised incidence rates and incidence rate ratios were calculated for migrant and native groups.

RESULTS

We found higher rates of admissions for psychosis in the migrant group (IRR 2.9, 95 % CI 0.9-9.8) compared to individuals born in France. Among migrants, incidence was higher in individuals from Sub-Saharan Africa compared to natives (IRR 7.1, CI 95 % 2.3-21.8), whereas the incidence was similar for those from Europe (IRR 1.2, CI 95 % 0.3-5.1) and from North Africa (IRR 1.4, CI 95 % 0.4-5.6).

CONCLUSIONS

Our findings suggest that Sub-Saharan migrants were identified as the most vulnerable migrant group for developing psychosis in France, but additional work is warranted to confirm these trends.

High prevalence of Human Herpesvirus 8 in schizophrenic patients

Many studies have reported an association between Herpes family viruses and an increased risk of schizophrenia, but the role of Human Herpesvirus 8 (HHV8) has never been investigated. This study aimed to assess HHV8 prevalence in schizophrenic patients as well as the possible association between HHV8 infection and schizophrenia clinical features. We consecutively enrolled 108 patients meeting fourth edition of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria of schizophrenia and 108 age and sex matched controls. Data about a number of demographic characteristics and potential HHV8 risk factors of infection were collected. Standardized psychopathology measures, disease severity and functioning level were obtained using Positive and Negative Syndrome Scale (PANSS), Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Negative Symptoms (SANS), Scale for the Assessment of Positive Symptoms (SAPS), Clinical Global Impressions (CGI) and Global Assessment of functioning (GAF). The presence of anti-HHV8 antibodies was analyzed using an indirect immunofluorescence assay. A higher prevalence of HHV8 infection in schizophrenic patients than in controls was found. Marital status, having children, sexual behavior and risk factors of blood transmission were not associated with HHV8 prevalence. However, among schizophrenic patients, HHV8 prevalence was statically associated with positive symptoms. To our knowledge, this would be the first report of a possible role of HHV8 in the pathogenesis of schizophrenia. To prove this hypothesis, further investigation of HHV8 in schizophrenia with larger samples is needed.

High seroprevalence of Toxoplasma gondii infection in inmates: A case control study in Durango City, Mexico

PURPOSE

The seroprevalence of infection with the parasite Toxoplasma gondii and the association with risk factors has not been determined in inmates. Through a case-control study, 166 inmates from a state correctional facility in Durango City, Mexico and 166 age- and gender-matched non-incarcerated subjects were examined for the presence of anti-T. gondii IgG and IgM antibodies using enzyme-linked immunoassays.

RESULTS

Seroprevalence of anti-T. gondii IgG antibodies was higher in inmates (35, 21.1%) than in controls (14, 8.4%) (OR = 2.90; 95% CI: 1.43-5.94; P = 0.001). Anti-T. gondii IgM antibodies were detected in two (1.2%) inmates and in seven (4.2%) controls (P = 0.17). Multivariate analysis of socio-demographic, incarceration, and behavioral characteristics of inmates revealed that T. gondii seropositivity was associated with being born out of Durango State (OR = 3.91; 95% CI: 1.29-11.79; P = 0.01). In addition, T. gondii seroprevalence was higher (P = 0.03) in inmates that had suffered from injuries (17/56: 30.4%) than those without such history (18/110: 16.4%).

CONCLUSIONS

The seroprevalence of T. gondii infection in inmates in Durango City is higher than the seroprevalences found in the general population in the same city, indicating that inmates may represent a new risk group for T. gondii infection. Further research on T. gondii infection in inmates is needed.

Comparative analysis of anti-toxoplasmic activity of antipsychotic drugs and valproate

Recent studies have shown a strong link between Toxoplasma gondii infection and psychiatric disorders, especially schizophrenia and bipolar disorders (odd ratio ≈2.7 for each disorder). Antipsychotic drugs and mood stabilizers may have anti-toxoplasmic activity that potentially may be associated with better effectiveness in these disorders, but previous results have been few in number and conflicting. We therefore sought to determine which daily prescribed antipsychotics and mood stabilizer have the best anti-toxoplasmic activity during the development phase of the parasite. In the present study, we examined the effects of commonly used antipsychotic drugs (amisulpride, cyamemazine, fluphenazine, haloperidol, levomepromazine, loxapine, olanzapine, risperidone and tiapride) and one mood-stabilizing agent (valproate) on toxoplasmic activity. We replicated that fluphenazine has a high anti-toxoplasmic activity, but it does not seem to be a phenothiazine-specific class effect: indeed, we found that another first-generation antipsychotic, zuclopenthixol, has a high anti-toxoplasmic activity. Valproate, tiapride and amisulpride have no anti-toxoplasmic activity on parasite growth, and the other antipsychotic drugs showed low or intermediate anti-toxoplasmic activity. As it is not possible to know the intracellular concentrations of antipsychotics in the brain, further clinical studies are warranted to determine whether these in vitro findings have potential implications in treatment of toxo-positive patients with schizophrenia. These findings may be potentially relevant for the choice of the first-line antipsychotic drug or mood stabilizer in previously infected patients.

The role of microbes and autoimmunity in the pathogenesis of neuropsychiatric illness

PURPOSE OF REVIEW

To illustrate how microbes might participate in the pathogenesis of neuropsychiatric illness by triggering the production of autoantibodies that bind to brain targets.

RECENT FINDINGS

Some studies link exposure to infectious agents to development of brain disorders; others have identified autoantibodies in individuals with these conditions without finding evidence of pathogens. Neither line of work demonstrates consistent associations between a specific neuropsychiatric disease and a particular environmental trigger or immune marker. Growing evidence suggests that the microbiome conditions host immunity to microbes and xenobiotics, and regulates autoimmune responses that can affect the central nervous system (CNS). The presence of CNS receptors for cytokines and other immune molecules underscores the importance of brain-immune crosstalk in maintaining normal function. An increased prevalence of familial autoimmunity, exposure to pathogens prenatally and postnatally, and findings of antibrain antibodies is common in disorders as diverse as schizophrenia, obsessive-compulsive disorder and autism, and suggests that differences in exposure timing and genetic vulnerability toward autoimmunity are important determinants of neuropsychiatric outcomes.

SUMMARY

Microbes, both pathogenic and commensal, can induce autoantibodies that bind to brain and affect behavior in susceptible hosts. Interventions that correct the microbial balance or diminish autoantibody binding may be effective in diverse neuropsychiatric conditions mediated by autoimmunity.

Pre-clinical models of neurodevelopmental disorders: focus on the cerebellum

Recent studies have advanced our understanding of the role of the cerebellum in non-motor behaviors. Abnormalities in the cerebellar structure have been demonstrated to produce changes in emotional, cognitive, and social behaviors resembling clinical manifestations observed in patients with autism spectrum disorders (ASD) and schizophrenia. Several animal models have been used to evaluate the effects of relevant environmental and genetic risk factors on the cerebellum development and function. However, very few models of ASD and schizophrenia selectively target the cerebellum and/or specific cell types within this structure. In this review, we critically evaluate the strength and weaknesses of these models. We will propose that the future progress in this field will require time- and cell type-specific manipulations of disease-relevant genes, not only selectively in the cerebellum, but also in frontal brain areas connected with the cerebellum. Such information can advance our knowledge of the cerebellar contribution to non-motor behaviors in mental health and disease.