Associations Between Non-neurological Autoimmune Disorders and Psychosis: A Meta-analysis

Causal role of immune cells in major depressive disorder and bipolar disorder: Mendelian randomization (MR) study

BACKGROUND

Major depressive disorder (MDD) and bipolar disorder (BD) are prevalent psychiatric conditions linked to inflammatory processes. However, it is unclear whether associations of immune cells with these disorders are likely to be causal.

METHODS

We used two-sample Mendelian randomization (MR) approach to investigate the relationship between 731 immune cells and the risk of MDD and BD. Rigorous sensitivity analyses are conducted to assess the reliability, heterogeneity, and horizontal pleiotropy of the findings.

RESULTS

Genetically-predicted CD27 on IgD+ CD38- unswitched memory B cell (inverse variance weighting (IVW): odds ratio (OR) [95 %]: 1.017 [1.007 to 1.027], p = 0.001), CD27 on IgD+ CD24+ B cell (IVW: OR [95 %]: 1.021 [1.011 to 1.031], p = 4.821E-05) and other 12 immune cells were associated with increased risk of MDD in MR, while HLA DR++ monocyte %leukocyte (IVW: OR [95 %]: 0.973 [0.948 to 0.998], p = 0.038), CD4 on Central Memory CD4+ T cell (IVW: OR [95 %]: 0.979 [0.963 to 0.995], p = 0.011) and other 13 immune cells were associated with decreased risk of MDD in MR. Additionally, CD33+ HLA DR+ Absolute Count (IVW: OR [95 %]: 1.022[1.007 to 1.036], p = 0.007), CD28+ CD45RA- CD8+ T cell %T cell (IVW: OR [95 %]: 1.024 [1.008 to 1.041], p = 0.004) and other 18 immune cells were associated with increased risk of BD in MR, while CD62L on CD62L+ myeloid Dendritic Cell (IVW: OR [95 %]: 0.926 [0.871 to 0.985], p = 0.014), IgD- CD27- B cell %lymphocyte (IVW: OR [95 %]: 0.918 [0.880 to 0.956], p = 4.654E-05) and other 13 immune cells were associated with decreased risk of BD in MR.

CONCLUSIONS

This MR study provides robust evidence supporting a causal relationship between immune cells and the susceptibility to MDD and BD, offering valuable insights for future clinical investigations. Experimental studies are also required to further examine causality, mechanisms, and treatment potential for these immune cells for MDD and BD.

Examining the Genetic Links between Clusters of Immune-mediated Diseases and Psychiatric Disorders

Importance

Autoimmune and autoinflammatory diseases have been linked to psychiatric disorders in the phenotypic and genetic literature. However, a comprehensive model that investigates the association between a broad range of psychiatric disorders and immune-mediated disease in a multivariate framework is lacking.

Objective

This study aims to establish a factor structure based on the genetic correlations of immune-mediated diseases and investigate their genetic relationships with clusters of psychiatric disorders.

Design Setting and Participants

We utilized Genomic Structural Equation Modeling (Genomic SEM) to establish a factor structure of 11 immune-mediated diseases. Genetic correlations between these immune factors were examined with five established factors across 13 psychiatric disorders representing compulsive, schizophrenia/bipolar, neurodevelopmental, internalizing, and substance use disorders. We included GWAS summary statistics of individuals of European ancestry with sample sizes from 1,223 cases for Addison's disease to 170,756 cases for major depressive disorder.

Main Outcomes and Measures

Genetic correlations between psychiatric and immune-mediated disease factors and traits to determine genetic overlap. We develop and validate a new heterogeneity metric, Q Factor , that quantifies the degree to which factor correlations are driven by more specific pairwise associations. We also estimate residual genetic correlations between pairs of psychiatric disorders and immune-mediated diseases.

Results

A four-factor model of immune-mediated diseases fit the data well and described a continuum from autoimmune to autoinflammatory diseases. The four factors reflected autoimmune, celiac, mixed pattern, and autoinflammatory diseases. Analyses revealed seven significant factor correlations between the immune and psychiatric factors, including autoimmune and mixed pattern diseases with the internalizing and substance use factors, and autoinflammatory diseases with the compulsive, schizophrenia/bipolar, and internalizing factors. Additionally, we find evidence of divergence in associations within factors as indicated by Q Factor . This is further supported by 14 significant residual genetic correlations between individual psychiatric disorders and immune-mediated diseases.

Conclusion and Relevance

Our results revealed genetic links between clusters of immune-mediated diseases and psychiatric disorders. Current analyses indicate that previously described relationships between specific psychiatric disorders and immune-mediated diseases often capture broader pathways of risk sharing indexed by our genomic factors, yet are more specific than a general association across all psychiatric disorders and immune-mediated diseases.

The relationship between schizophrenia or schizoaffective disorder and type 1 diabetes mellitus: a scoping review of observational studies

OBJECTIVE

Both schizophrenia and type 1 diabetes mellitus (T1D) are known as immune-related disorders. We systematically reviewed observational studies to explore the relationship between schizophrenia or schizoaffective disorder and T1D.

METHODS

A preliminary search of articles was completed using the following databases: Airiti Library, CINAHL Complete (via EBSCOhost), OVID MEDLINE, Embase, and PubMed. Two researchers independently assessed each study's quality based on Joanna Briggs Institute (JBI). A narrative review summarized the potential relationship between the two diseases.

RESULTS

Eleven studies were included in the final analysis. Six observational studies investigated the risk of schizophrenia and schizoaffective disorder in patients with T1D. Two studies showed negative correlations, one showed no correlation, and three showed positive correlations. On the other hand, five studies reported the prevalence of T1D in patients with schizophrenia. Two of them showed positive associations, and three others showed no association. Although the majority of the included studies suggested a positive association between the two medical conditions, these studies were still too heterogeneous to draw consistent results.

CONCLUSION

We found conflicting results regarding the bidirectional relationship between schizophrenia or schizoaffective disorder and T1D. These may stem from differences in study design, sampling methods, or definition of diagnoses, which are essential aspects to consider in future research.

Identification of Immune-Related Gene Signature in Schizophrenia

BACKGROUND

Schizophrenia (SCZ) is a type of psychiatric disorder characterized by multiple symptoms. Our aim is to decipher the relevant mechanisms of immune-related gene signatures in SCZ.

METHODS

The SCZ dataset and its associated immunoregulatory genes were retrieved using Gene Expression Omnibus (GEO) and single-sample gene set enrichment analysis (ssGSEA). Co-expressed gene modules were determined through weighted gene correlation network analysis (WGCNA). To elucidate the functional characteristics of these clusters, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used. Additionally, gene set enrichment analysis (GSEA) and Gene Set Variation Analysis (GSVA) were conducted to identify enriched pathways for the immune subgroups. A protein-protein interaction (PPI) network analysis was performed to identify core genes relevant to SCZ.

RESULTS

A significantly higher immune score was observed in SCZ compared to control samples. Seven distinct gene modules were identified, with genes highlighted in green selected for further analysis. Using the Cell-type Identification By Estimating Relative Subsets Of RNA Transcripts (CIBERSORT) method, degrees of immune cell adhesion and accumulation related to 22 different immune cell types were calculated. Significantly enriched bioprocesses concerning the immunoregulatory genes with differential expressions included interferon-beta, IgG binding, and response to interferon-gamma, according to GO and KEGG analyses. Eleven hub genes related to immune infiltration emerged as key players among the three top-ranked GO terms.

CONCLUSIONS

This study underscores the involvement of immunoregulatory reactions in SCZ development. Eleven immune-related genes (IFITM1 (interferon induced transmembrane protein 1), GBP1 (guanylate binding protein 1), BST2 (bone marrow stromal cell antigen 2), IFITM3 (interferon induced transmembrane protein 3), GBP2 (guanylate binding protein 2), CD44 (CD44 molecule), FCER1G (Fc epsilon receptor Ig), HLA-DRA (major histocompatibility complex, class II, DR alpha), FCGR2A (Fc gamma receptor IIa), IFI16 (interferon gamma inducible protein 16), and FCGR3B (Fc gamma receptor IIIb)) were identified as hub genes, representing potential biomarkers and therapeutic targets associated with the immune response in SCZ patients.

Exploring the Psychiatric Manifestations of Primary Sjögren's Syndrome: A Narrative Review

Background

Primary Sjögren's syndrome (pSS) is recognized for its autoimmune origin. Its hallmark symptoms, dry eyes and mouth, result from glandular inflammation. Prior literature indicates that pSS not only affects the peripheral system but also involves the central nervous system (CNS), giving rise to various neuropsychiatric symptoms. However, there is limited published research on the psychiatric comorbidities in individuals with pSS.

Methods

A comprehensive search was conducted on PubMed and Google Scholar for this narrative review. The search spanned from inception until August 2023. Its aim was to locate studies focusing on the psychiatric manifestations of pSS and the potential underlying mechanisms.

Results

The most commonly reported psychiatric complications among these individuals are depression and cognitive dysfunction. Other psychiatric manifestations that have been reported in pSS individuals include anxiety, sleep disorders, psychosis, catatonia, bipolar disorder, and obsessive-compulsive disorder.

Conclusion

In conclusion, patients with pSS often display multiple psychiatric symptoms. These symptoms can significantly impair functioning and reduce quality of life. Hence, prompt diagnosis and management are crucial.

The Finnish Adoptive Family Study of Schizophrenia: differences in somatic diseases and conditions between adoptees with high or low genetic risk for schizophrenia spectrum disorders

BACKGROUND AND AIMS

There is some evidence that offspring of patients with schizophrenia have higher somatic morbidity, which is thought to be partially due to genetic links between somatic disorders and schizophrenia. This study explored differences in somatic diseases and conditions of adoptees with high genetic risk (HR) or low genetic risk (LR) for schizophrenia spectrum disorders.

MATERIAL AND METHODS

The study is part of the Finnish Adoptive Family Study of Schizophrenia. The adoptive research design used made it possible to examine how the somatic health of adoptees raised in similar adoptive families, is affected by their genetic susceptibility to schizophrenia. The study sample consisted of 373 adoptees, of whom 190 had HR and 183 had LR for schizophrenia spectrum disorders. Data on somatic morbidity were gathered from the hospital records and from the national registers of the Care Register of Health Care and the Social Insurance Institution.

RESULTS

The only statistically significant difference found was in genitourinary diseases, the likelihood being twofold higher in HR adoptees compared to LR adoptees (16.8% vs. 8.2%; adj. OR = 2.13, 95% CI 1.06-4.25, p = .033). Adoptees who were female and aged over 40 had a higher prevalence of genitourinary illnesses than non-adoptees.

CONCLUSION

The significant prevalence of genitourinary diseases in adoptees at risk for schizophrenia spectrum disorders suggests that some specific somatic diseases and schizophrenia may have a shared hereditary etiology. More research is required for specific somatic diseases in study populations that can differentiate between the effects of genetic and environmental factors.

Multimorbidity and the Etiology of Schizophrenia

PURPOSE OF REVIEW

A global study of multimorbidity in schizophrenia, especially of the association with physical conditions, might offer much needed etiological insights.

RECENT FINDINGS

Our review suggests that life-style factors and medication related to schizophrenia are only part of the explanation of the increase in risk for cardiovascular, metabolic, pulmonary disorders, and some cancers. Positive associations with autoimmune disorders (with the exception of rheumatoid arthritis) and epilepsy are promising avenues of research but to date have not been fully exploited. The same holds for the negative comorbidity seen for rheumatoid arthritis and some cancers (e.g., prostate). As a whole, our review suggests that most of the explored conditions have a different prevalence in schizophrenia than in the general population. Several hypotheses emerged from this review such as the role of immune and genetic factors, of sex hormones, and of more general variability factors.

T cell-mediated skin-brain axis: Bridging the gap between psoriasis and psychiatric comorbidities

Psoriasis, a chronic inflammatory skin condition, is often accompanied by psychiatric comorbidities such as anxiety, depression, suicidal ideation, and other mental disorders. Psychological disorders may also play a role in the development and progression of psoriasis. The intricate interplay between the skin diseases and the psychiatric comorbidities is mediated by the 'skin-brain axis'. Understanding the mechanisms underlying psoriasis and psychiatric comorbidities can help improve the efficacy of treatment by breaking the vicious cycle of diseases. T cells and related cytokines play a key role in the pathogenesis of psoriasis and psychiatric diseases, and are crucial components of the 'skin-brain axis'. Apart from damaging the blood-brain barrier (BBB) directly, T cells and secreted cytokines could interact with the hypothalamic-pituitary-adrenal axis (HPA axis) and the sympathetic nervous system (SNS) to exacerbate skin diseases or mental disorders. However, few reviews have systematically summarized the roles and mechanisms of T cells in the interaction between psoriasis and psychiatric comorbidities. In this review, we discussed several key T cells and their roles in the 'skin-brain axis', with a focus on the mechanisms underlying the interplay between psoriasis and mental commodities, to provide data that might help develop effective strategies for the treatment of both psoriasis and psychiatric comorbidities.

Immunophenotypes in psychosis: is it a premature inflamm-aging disorder?

Immunopsychiatric field has rapidly accumulated evidence demonstrating the involvement of both innate and adaptive immune components in psychotic disorders such as schizophrenia. Nevertheless, researchers are facing dilemmas of discrepant findings of immunophenotypes both outside and inside the brains of psychotic patients, as discovered by recent meta-analyses. These discrepancies make interpretations and interrogations on their roles in psychosis remain vague and even controversial, regarding whether certain immune cells are more activated or less so, and whether they are causal or consequential, or beneficial or harmful for psychosis. Addressing these issues for psychosis is not at all trivial, as immune cells either outside or inside the brain are an enormously heterogeneous and plastic cell population, falling into a vast range of lineages and subgroups, and functioning differently and malleably in context-dependent manners. This review aims to overview the currently known immunophenotypes of patients with psychosis, and provocatively suggest the premature immune "burnout" or inflamm-aging initiated since organ development as a potential primary mechanism behind these immunophenotypes and the pathogenesis of psychotic disorders.

Indicators of HSV1 Infection, ECM-Receptor Interaction, and Chromatin Modulation in a Nuclear Family with Schizophrenia

Schizophrenia (SCZ) is a complex psychiatric disorder with high heritability; identifying risk genes is essential for deciphering the disorder's pathogenesis and developing novel treatments. Using whole-exome sequencing, we screened for mutations within protein-coding sequences in a single family of patients with SCZ. In a pathway enrichment analysis, we found multiple transmitted variant genes associated with two KEGG pathways: herpes simplex virus 1 (HSV1) infection and the extracellular matrix (ECM)-receptor interaction. When searching for rare variants, six variants, SLC6A19p.L541R, CYP2E1p.T376S, NAT10p.E811D, N4BP1p.L7V, CBX2p.S520C, and ZNF460p.K190E, segregated with SCZ. A bioinformatic analysis showed that three of these mutated genes were associated with chromatin modulation. We found that HSV1 infection, ECM-receptor interaction pathways, and epigenetic mechanisms may contribute to the pathogenesis of SCZ in certain families. The identified polygenetic risk factors from the sample family provide distinctive underlying biological mechanisms of the pathophysiology of SCZ and may be useful in clinical practice and patient care.

The association between exposure to clozapine, olanzapine, and quetiapine and the outcomes perimyocarditis and heart failure: A population-based cohort study

The risk of cardiac adverse events following clozapine use is debated and is unknown for the chemically related and widely used antipsychotics olanzapine and quetiapine. National Swedish registers were used to identify all patients 16-75 years old with antipsychotic dispensations between 2005 and 2018. The short-term outcome was a diagnosis of perimyocarditis (pericarditis and/or myocarditis) within two months of first dispensation, and the long-term outcome was heart failure (including cardiomyopathy) within three years. Cox regressions with time varying exposure were used to estimate hazard rates (HR) and their 95% confidence intervals (CI). A total of 201,045 individuals were included in the cohort. The risk of developing perimyocarditis during clozapine treatment tripled compared to no antipsychotic treatment (HR 3.4, CI 1.6-7.3), although the absolute rate remained comparably low. The long-term risk of heart failure during clozapine treatment was also elevated (HR 1.3, CI 1.1-1.7). Treatment with either or both olanzapine or quetiapine was not associated with an increased relative risk of perimyocarditis, or heart failure compared to no antipsychotic treatment. Clozapine use is therefore associated with a substantially elevated short-term risk of perimyocarditis and an increased risk of heart failure within three years.

The association between peripheral inflammation, brain glutamate and antipsychotic response in Schizophrenia: Data from the STRATA collaboration

Glutamate and increased inflammation have been separately implicated in the pathophysiology of schizophrenia and the extent of clinical response to antipsychotic treatment. Despite the mechanistic links between pro-inflammatory and glutamatergic pathways, the relationships between peripheral inflammatory markers and brain glutamate in schizophrenia have not yet been investigated. In this study, we tested the hypothesis that peripheral levels of pro-inflammatory cytokines would be positively associated with brain glutamate levels in schizophrenia. Secondary analyses determined whether this relationship differed according to antipsychotic treatment response. The sample consisted of 79 patients with schizophrenia, of whom 40 were rated as antipsychotic responders and 39 as antipsychotic non-responders. Brain glutamate levels were assessed in the anterior cingulate cortex (ACC) and caudate using proton magnetic resonance spectroscopy (1H-MRS) and blood samples were collected for cytokine assay on the same study visit (IL-6, IL-8, IL-10, TNF- α and IFN-γ). Across the whole patient sample, there was a positive relationship between interferon-gamma (IFN-γ) and caudate glutamate levels (r = 0.31, p = 0.02). In the antipsychotic non-responsive group only, there was a positive relationship between interleukin-8 (IL-8) and caudate glutamate (r = 0.46, p = 0.01). These findings provide evidence to link specific peripheral inflammatory markers and caudate glutamate in schizophrenia and may suggest that this relationship is most marked in patients who show a poor response to antipsychotic treatment.

Analyzing schizophrenia-related phenotypes in mice caused by autoantibodies against NRXN1α in schizophrenia

The molecular pathological mechanisms underlying schizophrenia remain unclear; however, genomic analysis has identified genes encoding important risk molecules. One such molecule is neurexin 1α (NRXN1α), a presynaptic cell adhesion molecule. In addition, novel autoantibodies that target the nervous system have been found in patients with encephalitis and neurological disorders. Some of these autoantibodies inhibit synaptic antigen molecules. Studies have examined the association between schizophrenia and autoimmunity; however, the pathological data remain unclear. Here, we identified a novel autoantibody against NRXN1α in patients with schizophrenia (n = 2.1%) in a Japanese cohort (n = 387). None of the healthy control participants (n = 362) were positive for anti-NRXN1α autoantibodies. Anti-NRXN1α autoantibodies isolated from patients with schizophrenia inhibited the molecular interaction between NRXN1α and Neuroligin 1 (NLGN1) and between NRXN1α and Neuroligin 2 (NLGN2). Additionally, these autoantibodies reduced the frequency of the miniature excitatory postsynaptic current in the frontal cortex of mice. Administration of anti-NRXN1α autoantibodies from patients with schizophrenia into the cerebrospinal fluid of mice reduced the number of spines/synapses in the frontal cortex and induced schizophrenia-related behaviors such as reduced cognition, impaired pre-pulse inhibition, and reduced social novelty preference. These changes were improved through the removal of anti-NRXN1α autoantibodies from the IgG fraction of patients with schizophrenia. These findings demonstrate that anti-NRXN1α autoantibodies transferred from patients with schizophrenia cause schizophrenia-related pathology in mice. Removal of anti-NRXN1α autoantibodies may be a therapeutic target for a subgroup of patients who are positive for these autoantibodies.

Evaluation of Brain-Body Health in Individuals With Common Neuropsychiatric Disorders

Importance

Physical health and chronic medical comorbidities are underestimated, inadequately treated, and often overlooked in psychiatry. A multiorgan, systemwide characterization of brain and body health in neuropsychiatric disorders may enable systematic evaluation of brain-body health status in patients and potentially identify new therapeutic targets.

Objective

To evaluate the health status of the brain and 7 body systems across common neuropsychiatric disorders.

Design, Setting, and Participants

Brain imaging phenotypes, physiological measures, and blood- and urine-based markers were harmonized across multiple population-based neuroimaging biobanks in the US, UK, and Australia, including UK Biobank; Australian Schizophrenia Research Bank; Australian Imaging, Biomarkers, and Lifestyle Flagship Study of Ageing; Alzheimer's Disease Neuroimaging Initiative; Prospective Imaging Study of Ageing; Human Connectome Project-Young Adult; and Human Connectome Project-Aging. Cross-sectional data acquired between March 2006 and December 2020 were used to study organ health. Data were analyzed from October 18, 2021, to July 21, 2022. Adults aged 18 to 95 years with a lifetime diagnosis of 1 or more common neuropsychiatric disorders, including schizophrenia, bipolar disorder, depression, generalized anxiety disorder, and a healthy comparison group were included.

Main Outcomes and Measures

Deviations from normative reference ranges for composite health scores indexing the health and function of the brain and 7 body systems. Secondary outcomes included accuracy of classifying diagnoses (disease vs control) and differentiating between diagnoses (disease vs disease), measured using the area under the receiver operating characteristic curve (AUC).

Results

There were 85 748 participants with preselected neuropsychiatric disorders (36 324 male) and 87 420 healthy control individuals (40 560 male) included in this study. Body health, especially scores indexing metabolic, hepatic, and immune health, deviated from normative reference ranges for all 4 neuropsychiatric disorders studied. Poor body health was a more pronounced illness manifestation compared to brain changes in schizophrenia (AUC for body = 0.81 [95% CI, 0.79-0.82]; AUC for brain = 0.79 [95% CI, 0.79-0.79]), bipolar disorder (AUC for body = 0.67 [95% CI, 0.67-0.68]; AUC for brain = 0.58 [95% CI, 0.57-0.58]), depression (AUC for body = 0.67 [95% CI, 0.67-0.68]; AUC for brain = 0.58 [95% CI, 0.58-0.58]), and anxiety (AUC for body = 0.63 [95% CI, 0.63-0.63]; AUC for brain = 0.57 [95% CI, 0.57-0.58]). However, brain health enabled more accurate differentiation between distinct neuropsychiatric diagnoses than body health (schizophrenia-other: mean AUC for body = 0.70 [95% CI, 0.70-0.71] and mean AUC for brain = 0.79 [95% CI, 0.79-0.80]; bipolar disorder-other: mean AUC for body = 0.60 [95% CI, 0.59-0.60] and mean AUC for brain = 0.65 [95% CI, 0.65-0.65]; depression-other: mean AUC for body = 0.61 [95% CI, 0.60-0.63] and mean AUC for brain = 0.65 [95% CI, 0.65-0.66]; anxiety-other: mean AUC for body = 0.63 [95% CI, 0.62-0.63] and mean AUC for brain = 0.66 [95% CI, 0.65-0.66).

Conclusions and Relevance

In this cross-sectional study, neuropsychiatric disorders shared a substantial and largely overlapping imprint of poor body health. Routinely monitoring body health and integrated physical and mental health care may help reduce the adverse effect of physical comorbidity in people with mental illness.

Patients with schizophrenia and bipolar disorder display a similar global gene expression signature in whole blood that reflects elevated proportion of immature neutrophil cells with association to lipid changes

Schizophrenia (SCZ) and bipolar disorder (BD) share clinical characteristics, genetic susceptibility, and immune alterations. We aimed to identify differential transcriptional patterns in peripheral blood cells of patients with SCZ or BD versus healthy controls (HC). We analyzed microarray-based global gene expression data in whole blood from a cohort of SCZ (N = 329), BD (N = 203) and HC (N = 189). In total, 65 genes were significantly differentially expressed in SCZ and 125 in BD, as compared to HC, with similar ratio of up- and downregulated genes in both disorders. Among the top differentially expressed genes, we found an innate immunity signature that was shared between SCZ and BD, consisting of a cluster of upregulated genes (e.g., OLFM4, ELANE, BPI and MPO) that indicate an increased fraction of immature neutrophils. Several of these genes displayed sex differences in the expression pattern, and post-hoc analysis demonstrated a positive correlation with triglyceride and a negative correlation with HDL cholesterol. We found that many of the downregulated genes in SCZ and BD were associated with smoking. These findings of neutrophil granulocyte-associated transcriptome signatures in both SCZ and BD point at altered innate immunity pathways with association to lipid changes and potential for clinical translation.

Serum immune markers and transition to psychosis in individuals at clinical high risk

Individuals at clinical high risk (CHR) for psychosis have been found to have altered cytokine levels, but whether these changes are related to clinical outcomes remains unclear. We addressed this issue by measuring serum levels of 20 immune markers in 325 participants (n = 269 CHR, n = 56 healthy controls) using multiplex immunoassays, and then followed up the CHR sample to determine their clinical outcomes. Among 269 CHR individuals, 50 (18.6 %) developed psychosis by two years. Univariate and machine learning techniques were used to compare levels of inflammatory markers in CHR subjects and healthy controls, and in CHR subjects who had (CHR-t), or had not (CHR-nt) transitioned to psychosis. An ANCOVA identified significant group differences (CHR-t, CHR-nt and controls) and post-hoc tests indicated that VEGF levels and the IL-10/IL-6 ratio were significantly higher in CHR-t than CHR-nt, after adjusting for multiple comparisons. Using a penalised logistic regression classifier, CHR participants were distinguished from controls with an area-under the curve (AUC) of 0.82, with IL-6 and IL-4 levels the most important discriminating features. Transition to psychosis was predicted with an AUC of 0.57, with higher VEGF level and IL-10/IL-6 ratio the most important discriminating features. These data suggest that alterations in the levels of peripheral immune markers are associated with the subsequent onset of psychosis. The association with increased VEGF levels could reflect altered blood-brain-barrier (BBB) permeability, while the link with an elevated IL-10/IL-6 ratio points to an imbalance between anti- and pro-inflammatory cytokines.

The deficit subtype of schizophrenia is associated with a pro-inflammatory phenotype but not with altered levels of zonulin: Findings from a case-control study

There is evidence that subclinical inflammation and increased gut permeability might be involved in the pathophysiology of schizophrenia. Less is known about these phenomena in patients with the deficit subtype of schizophrenia (D-SCZ) characterized by primary and enduring negative symptoms. Therefore, in the present study we aimed to compare the levels of zonulin (the marker of gut permeability) and immune-inflammatory markers in patients with D-SCZ, those with non-deficit schizophrenia (ND-SCZ) and healthy controls (HCs). A total of 119 outpatients with schizophrenia and 120 HCs were enrolled. The levels of 26 immune-inflammatory markers and zonulin were determined in serum samples. The following between-group differences were significant after adjustment for multiple testing and the effects of potential confounding factors: 1) higher levels of interleukin(IL)- 1β and C-reactive protein (CRP) in patients with D-SCZ compared to those with ND-SCZ and HCs; 2) higher levels of tumor necrosis factor-α and RANTES in both groups of patients with schizophrenia compared to HCs and 3) higher levels of IL-17 in patients with D-SCZ compared to HCs. No significant between-group differences in zonulin levels were found. Higher levels of IL-1β and CRP were associated with worse performance of attention after adjustment for age, education and chlorpromazine equivalents. Also, higher levels of IL-1β were correlated with greater severity of negative symptoms after adjustment for potential confounding factors. In conclusion, individuals with D-SCZ are more likely to show subclinical inflammation. However, findings from the present study do not support the hypothesis that this phenomenon is secondary to increased gut permeability.

Association between autoimmune diseases of the nervous system and schizophrenia: A systematic review and meta-analysis of cohort studies

INTRODUCTION

Numerous studies have found an association between autoimmune diseases of the nervous system (ADNS) and schizophrenia (SCZ), but the findings remain controversial. We conducted the first meta-analysis to summarize the current evidence from cohort studies that evaluated the association between ADNS and SCZ.

METHODS

PubMed, Web of Science, and Embase were comprehensively searched until May 30, 2022 for articles on the association between ADNS and SCZ. Every included study was reported effect size with 95% CIs for the association between ADNS and SCZ. Meta-regression and subgroup analysis were used to assess the heterogeneity.

RESULTS

A total of 8 cohort studies with 12 cohorts were included in the meta-analysis. We observed a significant association between ADNS and SCZ (RR = 1.42; 95%CI, 1.18-1.72). Subgroup analysis showed that the risk of SCZ was significantly increased when ADNS were used as exposure factors (RR = 1.48; 95%CI, 1.15-1.89), whereas with SCZ did not observe an increased risk of subsequent ADNS (RR = 1.33; 95%CI, 0.92-1.92); multiple sclerosis (MS) was positively associated with SCZ (RR = 1.36; 95%CI, 1.12-1.66), but no significant association was found between Guillain-Barre syndrome (GBS) and SCZ (RR = 1.90; 95%CI, 0.87-4.17). Meanwhile, we found location was the source of heterogeneity.

LIMITATIONS

High heterogeneity was observed (I² = 92.0%), and only English literature was included in the meta-analysis.

CONCLUSIONS

We found a positive association between ADNS and SCZ, and the association was different across the different types of ADNS. The results of the study are helpful for clinicians to carry out targeted preventive measures for ADNS and SCZ.

Complement Activation Products in Patients with Chronic Schizophrenia

Evidence suggests a role of the immune system in the pathogenesis of a number of mental conditions, including schizophrenia (SCH). In terms of physiology, aside from its crucial protective function, the complement cascade (CC) is a critical element of the regeneration processes, including neurogenesis. Few studies have attempted to define the function of the CC components in SCH. To shed more light on this topic, we compared the levels of complement activation products (CAP) (C3a, C5a and C5b-9) in the peripheral blood of 62 patients with chronic SCH and disease duration of ≥ 10 years with 25 healthy controls matched for age, sex, BMI and smoking status. Concentrations of all the investigated CAP were elevated in SCH patients. However, after controlling for potential confounding factors, significant correlations were observed between SCH and C3a (M = 724.98 ng/mL) and C5a (M = 6.06 ng/mL) levels. In addition, multivariate logistic regression showed that C3a and C5b-9 were significant predictors of SCH. There were no significant correlations between any CAP and SCH symptom severity or general psychopathology in SCH patients. However, two significant links emerged between C3a and C5b-9 and global functioning. Increased levels of both complement activation products in the patient group as compared to healthy controls raise questions concerning the role of the CC in the etiology of SCH and further demonstrate dysregulation of the immune system in SCH patients.

The association between ankylosing spondylitis and psychiatric disorders: Insights from a population based cross-sectional database

BACKGROUND

Ankylosing spondylitis (AS) is an inflammatory rheumatic disease involving the axial skeleton ultimately resulting in physical disability and psychological sequalae. The current study aims to evaluate the link between AS and psychiatric disorders, and to investigate the impact of different disease modifying drugs on such link.

METHODS

A large retrospective, population-based, cross-sectional study utilizing the Clalit-Health-Service (CHS) database was conducted on 5825 AS patients and 25,984 age- and sex-matched control individuals. The prevalence of psychiatric morbidity was compared between AS patients and age- and gender-matched controls. Predictors for psychiatric disorders in AS patients were also investigated.

RESULTS

The prevalence of psychiatric morbidity was higher in AS patients compared to controls (13.8 % vs. 9.8 %, p < 0.001). Similarly, major depression was positively associated with AS (OR 1.60, 95 % CI 1.43-1.79, p < 0.001), however, schizophrenia was negatively associated with AS (OR 0.60, 95 % CI 0.42-0.89, p < 0.011). Conventional DMARDs (cDMARDs) and anti-TNF used for management of AS were not shown to be predictors for psychiatric illnesses in AS patients.

CONCLUSIONS

Patients with AS are at a higher risk of developing psychiatric disorders, with increased risk of depression and lower risk of schizophrenia. cDMARDs and TNF-inhibitors are not predictors of psychiatric disorders in AS patients.

Early systemic inflammation induces neurodevelopmental disorders: results from ARTEMIS, a French multicenter study of juvenile rheumatisms and systemic autoimmune and auto-inflammatory disorders and meta-analysis

Prenatal immune-mediated events are known risk factors for neurodevelopmental disorders in the offspring (NDD). Although the brain continues to develop for years after birth and many postnatal factors alter the regular trajectory of neurodevelopment, little is known about the impact of postnatal immune factors. To fill this gap we set up ARTEMIS, a cohort of juvenile rheumatisms and systemic autoimmune and auto-inflammatory disorders (jRSAID), and assessed their neurodevelopment. We then complemented our results with a systematic review and meta-analysis. In ARTEMIS, we used unsupervised and supervised analysis to determine the influence of jRSAID age at onset (AO) and delay in introduction of disease-modifying therapy (DMT) on NDD (NCT04814862). For the meta-analysis, we searched MEDLINE, EMBASE, PsycINFO, Cochrane, and Web of Science up to April 2022 without any restrictions on language, or article type for studies investigating the co-occurence of jRSAID and NDD (PROSPERO- CRD42020150346). 195 patients were included in ARTEMIS. Classification tree isolated 3 groups of patients (i) A low-risk group (AO > 130 months (m)) with 5% of NDD (ii) A medium-risk group (AO < 130 m and DMT < 2 m) with 20% of NDD (iii) and a high-risk-group (AO < 130 m and DMT > 2 m) with almost half of NDD. For the meta-analysis, 18 studies encompassing a total of (i) 46,267 children with jRSAID; 213,930 children with NDD, and 6,213,778 children as controls were included. We found a positive association between jRSAID and NDD with an OR = 1.44 [95% CI 1.31; 1.57] p < 0.0001, [I² = 66%, Tau² = 0.0067, p < 0.01]. Several sensitivity analyses were performed without changing the results. Metaregression confirmed the importance of AO (p = 0.005). Our study supports the association between jRSAID and NDD. AO and DMT have pivotal roles in the risk of developing NDD. We plead for systematic screening of NDD in jRSAID to prevent the functional impact of NDD.

A rare case of schizophrenia coexistence with antiphospholipid syndrome, β-thalassemia, and monoclonal gammopathy of undetermined significance

A patient with schizophrenia who was treated with chlorpromazine developed lupus anticoagulant (LA) and antiphospholipid syndrome (APS). On protein electrophoresis, a monoclonal immunoglobulin A peak was seen in this patient, defining a condition of monoclonal gammopathy of undetermined significance. Additionally, β-thalassemia was diagnosed with the CD41-42 genotype. This condition is extremely rare, particularly in patients with schizophrenia and APS. We present a case of a patient with schizophrenia and secondary APS who had a positive LA, a significantly prolonged activated partial thromboplastin time, endogenous coagulation factor deficiency and inhibitor, no bleeding, and an unexpected finding of β-thalassemia and monoclonal IgA. Following that, a literature review on the disorders was presented.

Fingolimod ameliorates schizophrenia-like cognitive impairments induced by phencyclidine in male rats

BACKGROUND AND PURPOSE

Improvement of cognitive deficits in schizophrenia remains an unmet need owing to the lack of new therapies and drugs. Recent studies have reported that fingolimod, an immunomodulatory drug for treating multiple sclerosis, demonstrates anti-inflammatory and neuroprotective effects in several neurological disease models. This suggests its usefulness for ameliorating cognitive dysfunction in schizophrenia. Herein, we assessed the efficacy profile and mechanism of fingolimod in a rat model of phencyclidine (PCP)-induced schizophrenia.

EXPERIMENTAL APPROACH

Male Sprague-Dawley rats were treated with PCP for 14 days. The therapeutic effect of fingolimod on cognitive function was assessed using the Morris water maze and fear conditioning tests. Hippocampal neurogenesis and the expression of astrocytes and microglia were evaluated using immunostaining. Cytokine expression was quantified using multiplexed flow cytometry. Brain-derived neurotrophic factor expression and phosphorylation of extracellular signal-regulated kinase were determined using western blot analysis.

KEY RESULTS

Fingolimod attenuated cognitive deficits and restored hippocampal neurogenesis in a dose-dependent manner in PCP-treated rats. Fingolimod treatment exerted anti-inflammatory effects by inhibiting microglial activation and IL-6 and IL-1β pro-inflammatory cytokine expression. The underlying mechanism involves the upregulation of brain-derived neurotrophic factor protein expression and activation of the ERK signalling pathway.

CONCLUSION AND IMPLICATIONS

This is the first preclinical assessment of the effects of fingolimod on cognitive function in a model for schizophrenia. Our results suggest the immune system plays an crucial role in cognitive alterations in schizophrenia and highlight the potential of immunomodulatory strategies to improve cognitive deficits in schizophrenia.

Increased blood neutrophil extracellular traps (NETs) associated with early life stress: translational findings in recent-onset schizophrenia and rodent model

Higher levels of interleukin (IL)-6 and elevated neutrophil counts are consistently reported in the blood of patients with schizophrenia. Stressors during childhood and/or adolescence are major socioenvironmental risk factors for schizophrenia and may contribute to immune dysregulation. Previous studies using blood cytokines to stratify patients with schizophrenia suggest that only a subset presents a low-grade inflammatory state. However, these studies have not addressed whether environmental factors such as childhood maltreatment contributed to identifying inflammatory clusters. Moreover, a neutrophil-related mechanism (Neutrophil Extracellular Traps; NETs) central to both the initiation and chronicity of autoimmune and inflammatory diseases has never been investigated in psychiatry. Elevated NETs in schizophrenia may predispose patients to inflammatory and autoimmune diseases resulting in reduced life expectancy. We, therefore, investigated NETs as a novel mechanism and biological target in early schizophrenia and their role together with IL-6 and childhood maltreatment in identifying cluster subgroups. We found increased NETs in the plasma of patients with early schizophrenia (n = 78) compared to both their unaffected siblings (n = 25) and community controls (n = 78), irrespective of sex, body mass index, psychoactive drug use, or tobacco smoking. Increased NETs in patients were unrelated to antipsychotic treatment, which was further tested in vitro using fresh neutrophils. By applying unsupervised two-step clustering analysis, we integrated values of NETs, IL-6, and childhood maltreatment scores. We identified two main clusters; childhood maltreatment scores and NETs were the most important variables contributing to cluster separation (high-CL1 and low-CL2), while IL-6 was the least contributor. Patients allocated in the high-CL1 (61.5%) had significantly higher childhood maltreatment scores, NETs, and IL-6 levels than the remaining groups (patients low-CL2, siblings, and controls high-CL1 and low-CL2). We complemented these findings with a rat model based on stress exposure during adolescence that results in several schizophrenia-like changes in adulthood. We found that adolescent stressed rats had higher NETs and IL-6 levels in serum compared to non-stressed rats with a tendency to produce more NETs from the bone marrow. Altogether, this study brings a novel cellular-based mechanism in schizophrenia that, combined with early-stress, could be useful to identify subgroups for more personalised treatments.

Rare presence of autoantibodies targeting to NMDA and GABAA receptors in schizophrenia patients

BACKGROUND

Accumulating evidence suggests that the pathology of some psychiatric symptoms may relate to autoantibodies against various neuronal surface antigens, such as NMDA receptors (NMDARs) or inhibitory GABAA receptors (GABAARs). However, it is unclear whether the plasma of patients with schizophrenia contains autoantibodies targeting to NMDARs or GABAARs.

METHODS

Serum samples of 293 patients with schizophrenia were analyzed using a combination of live-cell-based assay (CBA) and immunostaining on primary neurons to quantify the positive rate of autoantibodies targeting NMDARs or GABA_ARs.

RESULTS

Only one sample was found positive for anti-NMDAR autoantibodies, and no surface autoantibodies against GABA_ARs were found. No obvious difference in clinical manifestations was observed between the patients with positive and negative anti-NMDAR autoantibodies.

CONCLUSIONS

Our results suggest that autoantibodies against NMDARs or GABAARs may affect only a small group of patients with schizophrenia, and the rates of these autoantibodies are lower than reported in prior work. It would be interesting to perform studies with psychotic disorder instead of schizophrenia to determine whether NMDAR or GABAAR autoantibody can be used as a biomarker to provide a new avenue for immunomodulatory therapy.

Immunologic profiling in schizophrenia and rheumatoid arthritis

The negative relationship between schizophrenia (SCZ) and rheumatoid arthritis (RA) has been observed for 85 years, but the mechanisms driving this association are unknown. This study analyzed differences in profiles of cytokines (IL-1β, IL-Ra, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IFNγ, TNFα), selected genes (HLA-DRB1, IL1RN, HP2), and antibodies related to gluten sensitivity (AGA-IgG, AGA-IgA), celiac disease (tTG), and systemic autoimmunity (ANA, anti-CCP, RF) in 40 subjects with SCZ, 40 with RA, and 40 healthy controls (HC). HLA-DRB1*04:01 alleles were enriched in persons with SCZ and RA compared with HC, and the HP2/HP2 genotype was 2-fold more prevalent in AGA/tTG-positive versus negative SCZ patients. Patients with SCZ demonstrated 52.5% positivity for any of the antibodies tested, compared to 90% of RA patients and 30% of HC. Cluster analysis of the cytokines revealed three clusters: one associated with SCZ marked by high levels of IL-1Ra, one associated with HC, and one associated with both SCZ and RA marked by elevated levels of IFNγ, TNFα, and IL-6. These analyses suggest that stratification of SCZ patients by cytokine profile may identify unique SCZ subgroups and enable the use of currently available cytokine-targeted treatment strategies.

The Role of Brain-Derived Neurotrophic Factor in Immune-Related Diseases: A Narrative Review

Brain-derived neurotrophic factor (BDNF) is a neurotrophin regulating synaptic plasticity, neuronal excitability, and nociception. It seems to be one of the key molecules in interactions between the central nervous system and immune-related diseases, i.e., diseases with an inflammatory background of unknown etiology, such as inflammatory bowel diseases or rheumatoid arthritis. Studies show that BDNF levels might change in the tissues and serum of patients during the course of these conditions, e.g., affecting cell survival and modulating pain severity and signaling pathways involving different neurotransmitters. Immune-related conditions often feature psychiatric comorbidities, such as sleep disorders (e.g., insomnia) and symptoms of depression/anxiety; BDNF may be related as well to them as it seems to exert an influence on sleep structure; studies also show that patients with psychiatric disorders have decreased BDNF levels, which increase after treatment. BDNF also has a vital role in nociception, particularly in chronic pain, hyperalgesia, and allodynia, participating in the formation of central hypersensitization. In this review, we summarize the current knowledge on BDNF's function in immune-related diseases, sleep, and pain. We also discuss how BDNF is affected by treatment and what consequences these changes might have beyond the nervous system.

Composite immune marker scores associated with severe mental disorders and illness course

Background

Low-grade inflammation has been implicated in the pathophysiology of severe mental disorders (SMDs) and a link between immune activation and clinical characteristics is suggested. However, few studies have investigated how patterns across immune markers are related to diagnosis and illness course.

Methods

A total of 948 participants with a diagnosis of schizophrenia (SCZ, N = 602) or bipolar (BD, N = 346) spectrum disorder, and 814 healthy controls (HC) were included. Twenty-five immune markers comprising cell adhesion molecules (CAMs), interleukin (IL)-18-system factors, defensins, chemokines and other markers, related to neuroinflammation, blood-brain barrier (BBB) function, inflammasome activation and immune cell orchestration were analyzed. Eight immune principal component (PC) scores were constructed by PC Analysis (PCA) and applied in general linear models with diagnosis and illness course characteristics.

Results

Three PC scores were significantly associated with a SCZ and/or BD diagnosis (HC reference), with largest, however small, effect sizes of scores based on CAMs, BBB markers and defensins (p < 0.001, partial η2 = 0.02-0.03). Number of psychotic episodes per year in SCZ was associated with a PC score based on IL-18 system markers and the potential neuroprotective cytokine A proliferation-inducing ligand (p = 0.006, partial η2 = 0.071).

Conclusion

Analyses of composite immune markers scores identified specific patterns suggesting CAMs-mediated BBB dysregulation pathways associated with SMDs and interrelated pro-inflammatory and neuronal integrity processes associated with severity of illness course. This suggests a complex pattern of immune pathways involved in SMDs and SCZ illness course.

Increased NLRP3 inflammasome expression in peripheral blood mononuclear cells of patients with schizophrenia: a case-control study

OBJECTIVE

This study aimed to evaluate the gene expression of the P2X purinoceptor 7 (P2X7R)- nod-like receptor pyrin domain-containing protein 3 (NLRP3) signal pathway in peripheral blood mononuclear cells (PBMCs) between schizophrenia (SCZ) patients and healthy controls (HC) to reveal its relationship with clinical variables.

METHODS

Thirty-two SCZ patients and 41 healthy controls were included in this study. The Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for the Assessment of Negative Symptoms (SANS), The Global Assessment of Functioning (GAF) scale and the Functioning Assessment Short Test (FAST) scales were applied. P2X7R, NLRP3, IL-1β and IL-18 gene expression levels were evaluated by real-time polymerase chain reaction in PBMCs.

RESULTS

NLRP3, P2RX7, IL-1β and IL-18 expression levels were significantly higher in PBMCs of SCZ patients than in HC subjects. Negative correlations were found between NLRP3 gene expression levels and GAF and FAST scales scores. There was a negative correlation between IL-18 expression levels and the GAF and FAST scales scores and a positive correlation with the SAPS scale scores.

CONCLUSIONS

Systemic inflammation is implicated in SCZ pathogenesis, according to our findings, which suggest that the NLRP3 pathway may be involved. The NLRP3 inflammasome may serve as a biomarker for SCZ, and its pharmacological regulation may be a promising treatment approach.Key pointsWe hypothesised that the NLRP3 pathway may contribute to the etiopathogenesis of schizophrenia.NLRP3, IL-1β and IL-18 mRNA levels were higher in patients with schizophrenia compared to healthy controls.Negative correlations were found between NLRP3 gene expression levels and GAF and FAST scales scores.There was a negative correlation between IL-18 expression levels and the GAF and FAST scales scores.The SAPS scale scores and IL-18 expression levels had a positive correlation.Given all these findings, it can be stated that NLRP3 inflammasome may play a role in the pathogenesis and symptoms of schizophrenia.

Association between parental mental illness and autoimmune diseases in the offspring - A nationwide register-based cohort study in Sweden

Mental illness has been previously linked with autoimmune diseases, yet the associations between parental mental illness and offspring's risk of autoimmune diseases is largely unknown. We conducted a population-based cohort study of 2,192,490 Swedish children born between 1991 and 2011 and their parents to determine the associations between parental mental illness and risk of autoimmune diseases among the offspring. Time-dependent diagnoses of parental mental illness (psychosis, alcohol/drug misuse, depression, anxiety, eating disorders, personality disorders, attention deficit hyperactivity disorder, autism spectrum disorder) and offspring autoimmune diseases (type 1 diabetes (T1D), juvenile idiopathic arthritis (JIA), systemic lupus erythematosus, psoriasis, multiple sclerosis, inflammatory bowel disease (IBD), coeliac disease) were identified from inpatient/outpatient healthcare visits. Associations were measured by hazard ratios (HRs) adjusted for potential confounders. Overall, parental mental illness was associated with a small increase in risk of offspring's autoimmune diseases (HR 1.05, 95% CI 1.02-1.08). However, parental common mental disorder (anxiety/depression) was associated with higher risk of JIA, psoriasis, and T1D (HR T1D 1.11, 95% CI 1.01-1.22), while maternal psychosis with reduced risk of coeliac disease (HR 0.68, 95% CI 0.49-0.95) and paternal alcohol/drug misuse with reduced risk of IBD (HR 0.80, 95% CI 0.64-0.99). Maternal eating disorders were associated with a markedly increased risk for T1D (HR 1.41, 95% CI 1.05-1.89). Further studies are needed to confirm these findings and to understand underlying mechanisms. There is a need for greater clinical awareness about potential risk of JIA, psoriasis, and T1D among children of parents with common psychiatric morbidity.

Brain anomalies in early psychosis: From secondary to primary psychosis

Brain anomalies are frequently found in early psychoses. Although they may remain undetected for many years, their interpretation is critical for differential diagnosis. In secondary psychoses, their identification may allow specific management. They may also shed light on various pathophysiological aspects of primary psychoses. Here we reviewed cases of secondary psychoses associated with brain anomalies, reported over a 20-year period in adolescents and young adults aged 13-30 years old. We considered age at first psychotic symptoms, relevant medical history, the nature of psychiatric symptoms, clinical red flags, the nature of the brain anomaly reported, and the underlying disease. We discuss the relevance of each brain area in light of normal brain function, recent case-control studies, and postulated pathophysiology. We show that anomalies in all regions, whether diffuse, multifocal, or highly localized, may lead to psychosis, without necessarily being associated with non-psychiatric symptoms. This underlines the interest of neuroimaging in the initial workup, and supports the hypothesis of psychosis as a global network dysfunction that involves many different regions.

Can epigenetics shine a light on the biological pathways underlying major mental disorders?

A significant proportion of the global burden of disease can be attributed to mental illness. Despite important advances in identifying risk factors for mental health conditions, the biological processing underlying causal pathways to disease onset remain poorly understood. This represents a limitation to implement effective prevention and the development of novel pharmacological treatments. Epigenetic mechanisms have emerged as mediators of environmental and genetic risk factors which might play a role in disease onset, including childhood adversity (CA) and cannabis use (CU). Particularly, human research exploring DNA methylation has provided new and promising insights into the role of biological pathways implicated in the aetio-pathogenesis of psychiatric conditions, including: monoaminergic (Serotonin and Dopamine), GABAergic, glutamatergic, neurogenesis, inflammatory and immune response and oxidative stress. While these epigenetic changes have been often studied as disease-specific, similarly to the investigation of environmental risk factors, they are often transdiagnostic. Therefore, we aim to review the existing literature on DNA methylation from human studies of psychiatric diseases (i) to identify epigenetic modifications mapping onto biological pathways either transdiagnostically or specifically related to psychiatric diseases such as Eating Disorders, Post-traumatic Stress Disorder, Bipolar and Psychotic Disorder, Depression, Autism Spectrum Disorder and Anxiety Disorder, and (ii) to investigate a convergence between some of these epigenetic modifications and the exposure to known risk factors for psychiatric disorders such as CA and CU, as well as to other epigenetic confounders in psychiatry research.

An Atlas of Genetic Correlations and Genetically Informed Associations Linking Psychiatric and Immune-Related Phenotypes

Importance

Certain psychiatric and immune-related disorders are reciprocal risk factors. However, the nature of these associations is unclear.

Objective

To characterize the pleiotropy between psychiatric and immune-related traits, as well as risk factors of hypothesized relevance.

Design, Setting, and Participants

This genetic association study was conducted from July 10, 2020, to January 15, 2022. Analyses used genome-wide association (GWA) statistics related to 14 psychiatric traits; 13 immune-related phenotypes, ie, allergic, autoimmune, and inflammatory disorders; and 15 risk factors related to health-related behaviors, social determinants of health, and stress response. Genetically correlated psychiatric-immune pairs were assessed using 2-sample mendelian randomization (MR) with sensitivity analyses and multivariable adjustment for genetic associations of third variables. False discovery rate correction (Q value < .05) was applied for each analysis.

Exposures

Genetic associations.

Main Outcomes and Measures

Genetic correlations and MR association estimates with SEs and P values. A data-driven approach was used that did not test a priori planned hypotheses.

Results

A total of 44 genetically correlated psychiatric-immune pairs were identified, including 31 positive correlations (most consistently involving asthma, Crohn disease, hypothyroidism, and ulcerative colitis) and 13 negative correlations (most consistently involving allergic rhinitis and type 1 diabetes). Correlations with third variables were especially strong for psychiatric phenotypes. MR identified 7 associations of psychiatric phenotypes on immune-related phenotypes that were robust to multivariable adjustment, including the positive association of (1) the psychiatric cross-disorder phenotype with asthma (odds ratio [OR], 1.04; 95% CI, 1.02-1.06), Crohn disease (OR, 1.09; 95% CI, 1.05-1.14), and ulcerative colitis (OR, 1.09; 95% CI, 1.05-1.14); (2) major depression with asthma (OR, 1.25; 95% CI, 1.13-1.37); (3) schizophrenia with Crohn disease (OR, 1.12; 95% CI, 1.05-1.18) and ulcerative colitis (OR, 1.14; 95% CI, 1.07-1.21); and a negative association of risk tolerance with allergic rhinitis (OR, 0.77; 95% CI, 0.67-0.92).

Conclusions and Relevance

Results of this genetic association study suggest that genetic liability for psychiatric disorders was associated with liability for several immune disorders, suggesting that vertical pleiotropy related to behavioral traits (or correlated third variables) contributes to clinical associations observed in population-scale data.

Where Sex Meets Gender: How Sex and Gender Come Together to Cause Sex Differences in Mental Illness

Sex differences are prevalent in multiple mental disorders. Internalizing disorders are more commonly diagnosed in women, whereas externalizing and neurodevelopmental disorders are more often diagnosed in men. Significant sex/gender differences are reported in prevalence, symptom profile, age of onset, comorbidities, functional impairment, prognosis, as well as in responses to various treatments. In this conceptual article, we discuss theories and empirical studies of sex- and gender-related influences in mental health, by focusing on three examples: autism spectrum disorder (ASD), acknowledged as a disorder whose roots are mainly biological; eating disorders, whose origins are considered to be mainly psychosocial, and posttraumatic stress disorder (PTSD), an environmentally caused disorder with both psychosocial and biological underpinnings. We examine the ways in which sex differences emerge, from conception through adulthood. We also examine how gender dichotomies in exposures, expectations, role assumptions, and cultural traditions impact the expression of our three selected mental illnesses. We are especially interested in how sex-based influences and gender-based influences interact with one another to affect mental illness. We suggest that sex and gender are multi-faceted and complex phenomena that result in variations, not only between men and women, but also within each sex and gender through alterations in genes, hormone levels, self-perceptions, trauma experiences, and interpersonal relationships. Finally, we propose a conceptual diatheses-stress model, depicting how sex and gender come together to result in multiple sex/gender differences across mental disorders. In our model, we categorize diatheses into several categories: biological, intrapersonal, interpersonal, and environmental. These diatheses interact with exposure to stressors, ranging from relatively minor to traumatic, which allows for the sometimes bidirectional influences of acute and long-term stress responses. Sex and gender are discussed at every level of the model, thereby providing a framework for understanding and predicting sex/gender differences in expression, prevalence and treatment response of mental disorders. We encourage more research into this important field of study.

Autoantibodies against NCAM1 from patients with schizophrenia cause schizophrenia-related behavior and changes in synapses in mice

From genetic and etiological studies, autoimmune mechanisms underlying schizophrenia are suspected; however, the details remain unclear. In this study, we describe autoantibodies against neural cell adhesion molecule (NCAM1) in patients with schizophrenia (5.4%, cell-based assay; 6.7%, ELISA) in a Japanese cohort (n = 223). Anti-NCAM1 autoantibody disrupts both NCAM1-NCAM1 and NCAM1-glial cell line-derived neurotrophic factor (GDNF) interactions. Furthermore, the anti-NCAM1 antibody purified from patients with schizophrenia interrupts NCAM1-Fyn interaction and inhibits phosphorylation of FAK, MEK1, and ERK1 when introduced into the cerebrospinal fluid of mice and also reduces the number of spines and synapses in frontal cortex. In addition, it induces schizophrenia-related behavior in mice, including deficient pre-pulse inhibition and cognitive impairment. In conclusion, anti-NCAM1 autoantibodies in patients with schizophrenia cause schizophrenia-related behavior and changes in synapses in mice. These antibodies may be a potential therapeutic target and serve as a biomarker to distinguish a small but treatable subgroup in heterogeneous patients with schizophrenia.

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Some patients with schizophrenia are positive for anti-NCAM1 autoantibodies

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Anti-NCAM1 antibody from schizophrenia patients inhibits NCAM1-NCAM1 interactions

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Anti-NCAM1 antibody from schizophrenia patients reduces spines and synapses in mice

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Anti-NCAM1 antibody from patients induces schizophrenia-related behavior in mice

Corneal in vivo Confocal Microscopy for Assessment of Non-Neurological Autoimmune Diseases: A Meta-Analysis

Purpose

This study aimed to evaluate the features of corneal nerve with in vivo confocal microscopy (IVCM) among patients with non-neurological autoimmune (NNAI) diseases.

Methods

We systematically searched PubMed, Web of Science, and Cochrane Central Register of Controlled Trials for studies published until May 2021. The weighted mean differences (WMDs) of corneal nerve fiber length (CNFL), corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), tortuosity, reflectivity, and beadings per 100 μm with a 95% CI between NNAI and control group were analyzed using a random-effects model.

Results

The results showed 37 studies involving collective totals of 1,423 patients and 1,059 healthy controls were ultimately included in this meta-analysis. The pooled results manifested significantly decreased CNFL (WMD: −3.94, 95% CI: −4.77–−3.12), CNFD (WMD: −6.62, 95% CI: −8.4–−4.85), and CNBD (WMD: −9.89, 95% CI: −14–−5.79) in NNAI patients. In addition, the NNAI group showed more tortuous corneal nerve (WMD: 1.19, 95% CI:0.57–1.81). The comparison between NNAI patients and healthy controls in beadings per 100 μm corneal nerve length was inconsistent. No significant difference was found in the corneal nerve fiber reflectivity between NNAI and the control group (WMD: −0.21, 95% CI: −0.65–0.24, P = 0.361).

Conclusions

The parameters and morphology of corneal nerves observed by IVCM proved to be different in NNAI patients from healthy controls, suggesting that IVCM may be a non-invasive technique for identification and surveillance of NNAI diseases.

Parental autoimmune and autoinflammatory disorders as multiple risk factors for common neurodevelopmental disorders in offspring: a systematic review and meta-analysis

Epidemiological studies have raised concerns about the risk of neurodevelopmental disorders (NDD) in children of patients with autoimmune or inflammatory disorders (AID). The pathophysiological pathways underlying this association are still unknown and little is known about the specific and distinct risk of each AID. To explore these questions, we investigated the association between the occurrences of several NDD in the offspring of mothers or fathers with different IDA. We conducted a meta-analysis-PROSPERO (CRD42020159250)-examining the risk of NDD in the offspring of mothers or fathers with AID. We performed specific analyses separately in fathers or mothers of NDD patients as well as subgroup analyses for each NDD and AID. We searched MEDLINE, Embase, PsycINFO, Cochrane Central Register of Controlled Trials, and Web of Science Core Collection published until December 2021. From an initial pool of 2074 potentially relevant references, 14 studies were included, involving more than 1,400,000 AID and 10,000,000 control parents, 180,000 children with NDD and more than 14,000,000 control children. We found AID in mothers (Adjusted OR 1.27 [95% CI 1.03; 1.57] p = 0.02, [I2 = 65%, Tau2 = 0.03 p = 0.01] and adjusted OR 1.31 [95% CI 1.11; 1.55] p = 0.001, [I2 = 93%, Tau2 = 0.13 p = 0.001] and, although in a lesser extent, in fathers (adjusted OR 1.18 [95% CI 1.07; 1.30] p = 0.01, [I2 = 15.5%, Tau2 = 0.002 p = 0.47]) and adjusted OR 1.14 [95% CI 1.10; 1.17] p < 0.0001, [I2 = 0%, Tau2 = 0 p = 0.29]) to be associated with ASD and ADHD in the offspring. This difference in the strength of the association was found in the AID-specific analyses, suggesting that AID increase the risk of NDD by a shared mechanism but that a specific maternal route appears to represent an additional excess risk. Inflammatory bowel disease were not associated with an additional risk (neither in fathers nor in mothers) of NDD in offspring. Our results suggest that complex and multiple AID-specific pathophysiological mechanisms may underlie the association of AID and NDD in offspring. Further, comprehensive studies of the different AID and NDD are needed to draw definitive conclusions about the pathophysiological links between parental AID and NDD in children.

Schizophrenia risk loci from xMHC region were associated with antipsychotic response in chronic schizophrenic patients with persistent positive symptom

We examined whether common variants from the extended major histocompatibility complex (xMHC) region contribute to the response to antipsychotic drugs (APDs) in patients with schizophrenia with persistent psychosis. Subjects participated in a prospective longitudinal study of the effect of APDs on psychopathology were temporally split into discovery (n = 88) and replication (n = 42) cohorts. The primary endpoint was a change in Brief Psychiatric Rating Scale at 6-week or 6-month after treatment. rs204991 (β = 3.917, p = 3.72 × 10^-6), the strongest signal associated with response at 6-week was located near C4A/C4B after a linear regression adjusted for covariates. xMHC SNP imputation disclosed much stronger signals (rs9268469, β = 5.140, p = 1.57 × 10^-7) and other weaker signals (p < 1 × 10^-5) spanning the entire xMHC region. All the variants were previously identified schizophrenia risk loci. Conditional fine-mapping revealed three subgroups of SNPs which were the eQTLs (p < 1 × 10^-7) for C4A, HLA-C, and BTN3A2 in disease-relevant tissue. Epistasis between HLA-C and C4A was observed (p = 0.019). Minor allele (G) carriers of rs204991, eQTL for C4A, having decreased risk for schizophrenia and lower imputed expression of C4A, had a better response to APDs. Some imputed HLA alleles associated with a decreased risk for schizophrenia had a positive association with improvement in psychotic symptoms. An independent cohort validated the association of change in psychosis with C4A. We provide evidence that genetic risk factors for schizophrenia from the xMHC region are associated with response to APDs and those variants significantly alter the imputed expression of C4A, HLA-C, and BTN3A2. The minor alleles predicting higher C4A level are associated with diminished improvement in psychotic symptoms after APD treatment.

Evidence From Imaging Resilience Genetics for a Protective Mechanism Against Schizophrenia in the Ventral Visual Pathway

INTRODUCTION

Illuminating neurobiological mechanisms underlying the protective effect of recently discovered common genetic resilience variants for schizophrenia is crucial for more effective prevention efforts. Current models implicate adaptive neuroplastic changes in the visual system and their pro-cognitive effects as a schizophrenia resilience mechanism. We investigated whether common genetic resilience variants might affect brain structure in similar neural circuits.

METHOD

Using structural magnetic resonance imaging, we measured the impact of an established schizophrenia polygenic resilience score (PRSResilience) on cortical volume, thickness, and surface area in 101 healthy subjects and in a replication sample of 33 224 healthy subjects (UK Biobank).

FINDING

We observed a significant positive whole-brain correlation between PRSResilience and cortical volume in the right fusiform gyrus (FFG) (r = 0.35; P = .0004). Post-hoc analyses in this cluster revealed an impact of PRSResilience on cortical surface area. The replication sample showed a positive correlation between PRSResilience and global cortical volume and surface area in the left FFG.

CONCLUSION

Our findings represent the first evidence of a neurobiological correlate of a genetic resilience factor for schizophrenia. They support the view that schizophrenia resilience emerges from strengthening neural circuits in the ventral visual pathway and an increased capacity for the disambiguation of social and nonsocial visual information. This may aid psychosocial functioning, ameliorate the detrimental effects of subtle perceptual and cognitive disturbances in at-risk individuals, and facilitate coping with the cognitive and psychosocial consequences of stressors. Our results thus provide a novel link between visual cognition, the vulnerability-stress concept, and schizophrenia resilience models.

Unmasking of Myasthenia Gravis After Introduction of Oral Risperidone in a Schizophrenic Saudi Male: A Case Report

Myasthenia gravis is an autoimmune disease that affects the neuromuscular junction. It causes generalized muscle weakness that may include the respiratory muscles, potentially leading to a medical emergency known as a myasthenic crisis. This is a case report of a rare incident of a myasthenia gravis exacerbation after administration of the oral antipsychotic risperidone to a schizophrenic patient. Few similar cases have been reported. Although rare, such incidents are dangerous as physicians could easily confuse myasthenia gravis symptoms with extrapyramidal side effects of antipsychotics. This concern should be addressed not just with risperidone but rather with any other antipsychotics that exhibit anticholinergic side effects.

Etiology and Risk Factors for Rheumatoid Arthritis: A State-of-the-Art Review

Rheumatoid arthritis (RA) is the most common systemic inflammatory rheumatic disease. It is associated with significant burden at the patient and societal level. Extensive efforts have been devoted to identifying a potential cause for the development of RA. Epidemiological studies have thoroughly investigated the association of several factors with the risk and course of RA. Although a precise etiology remains elusive, the current understanding is that RA is a multifactorial disease, wherein complex interactions between host and environmental factors determine the overall risk of disease susceptibility, persistence and severity. Risk factors related to the host that have been associated with RA development may be divided into genetic; epigenetic; hormonal, reproductive and neuroendocrine; and comorbid host factors. In turn, environmental risk factors include smoking and other airborne exposures; microbiota and infectious agents; diet; and socioeconomic factors. In the present narrative review, aimed at clinicians and researchers in the field of RA, we provide a state-of-the-art overview of the current knowledge on this topic, focusing on recent progresses that have improved our comprehension of disease risk and development.

Neuropsychiatric disorders: An immunological perspective

Neuropsychiatric diseases have traditionally been studied from brain, and mind-centric perspectives. However, mounting epidemiological and clinical evidence shows a strong correlation of neuropsychiatric manifestations with immune system activation, suggesting a likely mechanistic interaction between the immune and nervous systems in mediating neuropsychiatric disease. Indeed, immune mediators such as cytokines, antibodies, and complement proteins have been shown to affect various cellular members of the central nervous system in multitudinous ways, such as by modulating neuronal firing rates, inducing cellular apoptosis, or triggering synaptic pruning. These observations have in turn led to the exciting development of clinical therapies aiming to harness this neuro-immune interaction for the treatment of neuropsychiatric disease and symptoms. Besides the clinic, important theoretical fundamentals can be drawn from the immune system and applied to our understanding of the brain and neuropsychiatric disease. These new frameworks could lead to novel insights in the field and further potentiate the development of future therapies to treat neuropsychiatric disease.

Primary Psychosis: Risk and Protective Factors and Early Detection of the Onset

Primary psychosis, which includes schizophrenia and other psychoses not caused by other psychic or physical conditions, has a strong impact worldwide in terms of disability, suffering and costs. Consequently, improvement of strategies to reduce the incidence and to improve the prognosis of this disorder is a current need. The purpose of this work is to review the current scientific literature on the main risk and protective factors of primary psychosis and to examine the main models of prevention, especially those related to the early detection of the onset. The conditions more strongly associated with primary psychosis are socio-demographic and economic factors such as male gender, birth in winter, ethnic minority, immigrant status, and difficult socio-economic conditions while the best-established preventive factors are elevated socio-economic status and an economic well-being. Risk and protective factors may be the targets for primordial, primary, and secondary preventive strategies. Acting on modifiable factors may reduce the incidence of the disorder or postpone its onset, while an early detection of the new cases enables a prompt treatment and a consequential better prognosis. According to this evidence, the study of the determinants of primary psychosis has a pivotal role in designing and promoting preventive policies aimed at reducing the burden of disability and suffering of the disorder.

Exploring low grade inflammation by soluble urokinase plasminogen activator receptor levels in schizophrenia: a sex-dependent association with depressive symptoms

BACKGROUND

There is evidence of increased low grade inflammation (LGI) in schizophrenia patients. However, the inter-individual variation is large and the association with demographic, somatic and psychiatric factors remains unclear. Our aim was to explore whether levels of the novel LGI marker soluble urokinase plasminogen activator receptor (suPAR) were associated with clinical factors in schizophrenia and if such associations were sex-dependent.

METHOD

In this observational study a total of 187 participants with schizophrenia (108 males, 79 females) underwent physical examination and assessment with clinical interviews (Positive and Negative Syndrome Scale (PANSS), Calgary Depression Scale for Schizophrenia (CDSS), Alcohol Use Disorder Identification Test (AUDIT), and Drug Use Disorder Identification Test (DUDIT)). Blood levels of suPAR, glucose, lipids, and high sensitivity C-reactive protein (hsCRP) were determined and body mass index (BMI) calculated. Multivariable linear regression analyses were used adjusting for confounders, and sex interaction tested in significant variables.

RESULTS

Adjusting for sex, age, current tobacco smoking and BMI, we found that levels of hsCRP and depressive symptoms (CDSS) were positively associated with levels of suPAR (p < 0.001). The association between suPAR and CDSS score was significant in females (p < 0.001) but not in males. Immune activation measured by hsCRP was not associated with depressive symptoms after adjusting for BMI.

CONCLUSION

Our findings indicate that increased suPAR levels are associated with depressive symptoms in females with schizophrenia, suggesting aberrant immune activation in this subgroup. Our results warrant further studies, including longitudinal follow-up of suPAR levels in schizophrenia and experimental studies of mechanisms.

The future of immunopsychiatry: Three milestones to clinical innovation

Psychoneuroimmunology, the area of research dedicated to understanding the fundamental interactions between the central nervous system and the immune system, has given rise to the development of Immunopsychiatry, a new discipline which harnesses the immune system to produce beneficial outcomes for mental health problems. Immunopsychiatry has the potential to become a clinically relevant specialty area in psychiatric practice, but has not yet been adopted by the wider mental health community. This paper aims to map out the future trajectory of Immunopsychiatry on its road towards science-to-policy knowledge translation and clinical implementation. Three critical milestones which will need to be reached in order for Immunopsychiatry to fulfil its promise for clinical innovation are discussed: a clear definition of patients who fall within the immunopsychiatric continuum; demonstration of well-defined clinical benefit and incorporation in clinical guidelines; and convergence with other paradigms in biological psychiatry.

Immunological investigations of the cerebrospinal fluid in patients with recent onset psychotic disorders: A study protocol

BACKGROUND

Though many previous studies have indicated immunological alterations in psychotic disorders, the role and prevalence of neuroinflammation is still unknown. Studies previously investigating immune related biomarkers in the cerebrospinal fluid (CSF) of these patients are mainly small studies on few markers, and many have not compared patients to healthy controls.

METHODS

We will conduct a large case-control study including at least 100 patients with recent onset psychotic disorders and 100 sex- and age matched healthy controls. The cases will include patients diagnosed with a psychotic disorder according to ICD-10 (F20/F22-29) within a year prior to inclusion. We will collect both CSF, blood and fecal samples, to gain insight into possible immunological alterations. The psychopathology of all participants will thoroughly be evaluated using the SCAN interview, and multiple rating scales covering different symptom groups. All participants will partake in a detailed neurological examination, including the Neurological Evaluation Scale assessing neurological soft signs. Additionally, we will assess cognitive functioning, evaluate quality of life and level of functioning, and collect data on a broad array of possible confounders. Our primary outcomes will include CSF leucocytes, CSF/serum albumin ratio, CSF total protein, IgG index, CSF levels of IL-6 and IL-8, and presence of antineuronal autoantibodies in CSF and blood. For our secondary outcomes, exploratory analyses will be performed on a broader panel of neuroimmunological markers. All participants will be invited for a follow-up visit to assess longitudinal changes. The current study is part of a larger CSF biobank build-up for severe mental disorders (PSYCH-FLAME).

DISCUSSION

This study will represent the largest investigation of CSF in patients with psychotic disorders compared to healthy controls to date. We expect the study to contribute with new, important knowledge on pathophysiological mechanisms, and to help pave the way for future investigations of individualized treatment options.

TRIAL REGISTRATION

The study is approved by The Regional Committee on Health Research Ethics (Capital Region, j.no: H-16030985) and The Danish Data Protection Agency (j.no: RHP-2016-020, I-Suite no.: 04945).