A population-based study of atopic disorders and inflammatory markers in childhood before psychotic experiences in adolescence

VINDICATE-P: A Mnemonic for the Many Comorbidities of Atopic Dermatitis

Patients with atopic dermatitis (AD) are at increased risk of atopic and non-atopic comorbidities. In fact, the Hanifin and Rajka criteria include allergic and infectious comorbidities as a minor criterion. Despite the well-recognized list of comorbidities, the past 15 years greatly expanded the list of recognized comorbidities of AD. This narrative review focuses on comorbidities of AD using a mnemonic, VINDICATE-P: vascular/cardiovascular, infectious, neoplastic and neurologic, degenerative, iatrogenic, congenital, atopic and autoimmune, traumatic, endocrine/metabolic, and psychiatric. The comorbidities of AD vary by age. More research is needed into the mechanisms of comorbidities and optimal screening strategies in AD patients.

Immune and oxidative stress biomarkers in pediatric psychosis and psychosis-risk: Meta-analyses and systematic review

OBJECTIVE

While genetic and cohort studies suggest immune and reduction/oxidation (redox) alterations occur in psychosis, less is known about potential alterations in children and adolescents.

METHODS

We conducted a systematic review to identify immune and redox biomarker studies in children and adolescents (mean age ≤ 18 years old) across the psychosis spectrum: from psychotic like experiences, which are common in children, to threshold psychotic disorders like schizophrenia. We conducted meta-analyses when at least three studies measured the same biomarker.

RESULTS

The systematic review includes 38 pediatric psychosis studies. The meta-analyses found that youth with threshold psychotic disorders had higher neutrophil/lymphocyte ratio (Hedge's g = 0.40, 95 % CI 0.17 - 0.64), tumor necrosis factor (Hedge's g = 0.38, 95 % CI 0.06 - 0.69), C-reactive protein (Hedge's g = 0.38, 95 % CI 0.05 - 0.70), interleukin-6 (Hedge's g = 0.35; 95 % CI 0.11 - 0.64), and total white blood cell count (Hedge's g = 0.29, 95 % CI 0.12 - 0.46) compared to youth without psychosis. Other immune and oxidative stress meta-analytic findings were very heterogeneous.

CONCLUSION

Results from several studies are consistent with the hypothesis that signals often classified as "proinflammatory" are elevated in threshold pediatric psychotic disorders. Data are less clear for immune markers in subthreshold psychosis and redox markers across the subthreshold and threshold psychosis spectrum. Immune and redox biomarker intervention studies are lacking, and research investigating interventions targeting the immune system in threshold pediatric psychosis is especially warranted.

Effects of a six-month yoga intervention on the immune-inflammatory pathway in antipsychotic-stabilized schizophrenia patients: A randomized controlled trial

BACKGROUND

Schizophrenia is a complex neuropsychiatric disorder for which several etiopathological theories have been proposed, one of the prominent ones being immune dysfunction. Recent studies on yoga as an add-on therapy have shown improvement in negative symptoms, cognition, and quality of life in schizophrenia patients. However, the biological mechanism/s of action of yoga in schizophrenia are not clear. The current study was aimed at exploring the effects of long-term (6 months) add-on yoga therapy on the immune inflammatory pathway in schizophrenia patients.

METHODS

Sixty schizophrenia patients were randomized to add-on yoga therapy (YT=30) and treatment-as-usual (TAU=30) groups of which 21 patients in YT and 20 in TAU group completed the study. Blood samples and clinical assessments were obtained at baseline and at the end of 6 months. The plasma levels of nine cytokines (IL-2, IL-4, IL-5, IL-10, IL-12(p70), IL-13, GM-CSF, IFN-γ, and TNF-α) were quantified using multiplex suspension array. The clinical assessments included SAPS, SANS, BPRS, PSS, CGI, SOFS and WHOQUOL-BREF.

RESULTS

Patients in the yoga group showed significant reductions in plasma TNF-α (Z = 2.99, p = 0.003) and IL-5 levels (Z = 2.20, p = 0.03) and greater clinical improvements in SAPS, SANS, PSS, and SOFS scores as compared to TAU group. Further, plasma TNF-α levels exhibited a positive correlation with negative symptoms (r_s =0.45, p = 0.02) and socio-occupational functioning (r_s =0.61, p = 0.002) in the YT group.

CONCLUSIONS

The findings of the study suggest that improvements in schizophrenia psychopathology with yoga interventions are associated with immuno-modulatory effects.

Suicide and Suicidality in Children and Adolescents with Chronic Skin Disorders: A Systematic Review

Suicide in young children is rare; the incidence increases towards the end of adolescence. Skin disorders confer a high prevalence of psychiatric and psycho-logical comorbidities. However, published research on suicidal behaviour in adolescents and children with skin disorders is sparse. The aim of this study was to identify the prevalence of suicidal behaviour in children and adolescents under 18 years of age with chronic skin disorders and associated contributing risk factors. MEDLINE, PsycINFO, EMBASE, CINAHL and Cochrane databases were searched from inception to October 2020 for suicide or suicide attempts in patients under 18 years old with chronic skin disorders. The study protocol was logged on PROSPERO (CRD42020083528). Returned texts were reviewed independently by 2 authors. Bias was assessed according to Joanna Briggs Institute criteria. Five studies met the inclusion criteria; 4 cross-sectional surveys and 1 retrospective matched-cohort study. A total of 31,641 patients with acne, atopic dermatitis, body dysmorphic disorder or psoriasis were identified. Prevalence of suicidal ideation was 0.45% (psoriasis) to 67% (body dysmorphic disorder). The prevalence of suicidal attempts ranged from 0.08% (psoriasis) to 21.9% (acne). Patients with acne or atopic dermatitis had significantly increased odds ratio for suicidal attempts. Meta-analysis could not be performed owing to the heterogeneity and sparsity of data. Suicidal risk in skin disorders amongst adolescents and children under the age of 18 years old is broad and complex. The suicidal risk remained after adjusting for depression, suggestive of an alternative mechanism.

Atopic dermatitis and risk of major neuropsychiatric disorders in children: A population-based cohort study

BACKGROUND

Paediatric atopic dermatitis (AD) has been linked to neuropsychiatric comorbidities such as depression, anxiety and attention-deficit/hyperactivity disorder (ADHD). However, longitudinal data are limited, and the effect of AD severity on neuropsychiatric outcomes requires further characterization.

OBJECTIVES

To determine the risk of several major neuropsychiatric conditions in children with AD.

METHODS

We analysed UK health records data in a population-based cohort study. Each patient <18 years old with AD was matched to up to five unaffected patients on age, practice and index date. Treatments served as proxies for AD severity, which was analysed in a time-updated manner. Outcomes were incident anxiety, depression, bipolar disorder, schizophrenia, ADHD, autism, obsessive-compulsive disorder (OCD), suicidal ideation or attempt, and completed suicide.

RESULTS

A total of 409,431 children with AD (93.2% mild, 5.5% moderate, 1.3% severe) were compared to 1,809,029 children without AD. In Cox regression models adjusted for age, sex, socioeconomic status and other atopic comorbidities, no statistically significant relationships were observed between AD and incident anxiety (HR 1.01, 95% CI 0.99-1.03), ADHD (1.02, 0.97-1.06), autism (1.02, 0.98-1.06), bipolar disorder (1.08, 0.85-1.36), suicidal ideation/attempt (0.98, 0.95-1.01) or completed suicide (0.85, 0.64-1.14). Children with AD were less likely to develop depression (0.93, 0.91-0.95) or schizophrenia (0.72, 0.54-0.95) but more likely to develop OCD (1.26, 1.16-1.37). However, there was substantial variation by AD severity and age in both the direction and magnitude of effect for many of the neuropsychiatric conditions examined.

CONCLUSIONS

The was no substantial impact of AD on the overall risk of many neuropsychiatric conditions in children, but disease severity and age may be important modifying factors. Additional research is needed to further dissect the complex relationship between paediatric AD and neuropsychiatric comorbidities.

The association of asthma, atopic dermatitis, and allergic rhinitis with peripartum mental disorders

BACKGROUND

Atopic diseases are characterized by dysregulated inflammatory response, which may incur the onset of peripartum mental disorders, but the impact remains unknown. This study examined whether and to what extent the history of atopic diseases is associated with newly onset peripartum mental disorders.

METHODS

Using population-based registries, we identified all primiparous women who gave birth to live singletons in Denmark during 1978-2016 (n = 937,422). The exposure was hospital contact due to the three major types of atopic diseases-asthma, atopic dermatitis, and allergic rhinitis-before conception. The primary outcome was any hospital contact for mental disorder during pregnancy and 1-year postpartum, which was further classified into affective disorders, neurotic, stress-related and somatoform disorders, and substance abuse. The follow-up started from the date of conception and ended at the date of the first diagnosis of mental disorders, 1-year postpartum, death, emigration, or December 31, 2016, whichever came first. Cox regression was used, adjusted for calendar year, age at childbirth, education, residence, and Charlson comorbidity index.

RESULTS

A total of 24,016 (2.6%) women received diagnosis of at least one of the three atopic diseases before conception (asthma, 1.7%; atopic dermatitis, 0.6%; and allergic rhinitis, 0.8%). Exposure to asthma, atopic dermatitis, or allergic rhinitis was associated with a 37% increased overall risk of peripartum mental disorders (hazard ratio [HR], 1.37; 95% confidence interval [CI], 1.27-1.49). Higher risks were observed among women with more frequent hospital contacts for atopic disease (HR, 1.80; 95% CI, 1.37-2.35; ≥5 times), and with recent hospital contacts for atopic disease (HR, 1.74; 95% CI, 1.48-2.06; within 2 years before conception). Specific associations were observed between asthma and neurotic, stress-related and somatoform disorders (HR, 1.40; 95% CI, 1.21-1.62), and between atopic dermatitis and substance abuse (HR, 1.62; 95% CI, 1.12-2.34).

CONCLUSIONS

History of asthma, atopic dermatitis, and allergic rhinitis before conception was associated with increased risks of peripartum mental disorders. Women who have atopic diseases before pregnancy may benefit from systematic mental health monitoring.

The Microbiota/Microbiome and the Gut-Brain Axis: How Much Do They Matter in Psychiatry?

The functioning of the central nervous system (CNS) is the result of the constant integration of bidirectional messages between the brain and peripheral organs, together with their connections with the environment. Despite the anatomical separation, gut microbiota, i.e., the microorganisms colonising the gastrointestinal tract, is highly related to the CNS through the so-called "gut-brain axis". The aim of this paper was to review and comment on the current literature on the role of the intestinal microbiota and the gut-brain axis in some common neuropsychiatric conditions. The recent literature indicates that the gut microbiota may affect brain functions through endocrine and metabolic pathways, antibody production and the enteric network while supporting its possible role in the onset and maintenance of several neuropsychiatric disorders, neurodevelopment and neurodegenerative disorders. Alterations in the gut microbiota composition were observed in mood disorders and autism spectrum disorders and, apparently to a lesser extent, even in obsessive-compulsive disorder (OCD) and related conditions, as well as in schizophrenia. Therefore, gut microbiota might represent an interesting field of research for a better understanding of the pathophysiology of common neuropsychiatric disorders and possibly as a target for the development of innovative treatments that some authors have already labelled "psychobiotics".

Association between common early-childhood infection and subsequent depressive symptoms and psychotic experiences in adolescence: a population-based longitudinal birth cohort study

BACKGROUND

Childhood infections are associated with adult psychosis and depression, but studies of psychotic experiences (PEs) and depressive symptoms in childhood, adolescence, and early-adulthood are scarce. Previous studies have typically examined severe infections, but studies of common infections are also scarce.

METHODS

Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort, we examined associations of the number of infections in childhood from age 1.5 to 7.5 years with depressive symptom scores at age 10, 13, 14, 17, 18, and 19 years, and with PEs at 12 and 18 years. We performed additional analysis using infection burden ('low' = 0-4 infections, 'medium' = 5-6, 'high' = 7-9, or 'very high' = 10-22 infections) as the exposure.

RESULTS

The risk set comprised 11 786 individuals with childhood infection data. Number of childhood infections was associated with depressive symptoms from age 10 (adjusted beta = 0.14; standard error (s.e.) = 0.04; p = <0.01) to 17 years (adjusted beta = 0.17; s.e. = 0.08; p = 0.04), and with PEs at age 12 (suspected/definite PEs: adjusted odds ratio (OR) = 1.18; 95% confidence interval (CI) = 1.09-1.27). These effect sizes were larger when the exposure was defined as very high infection burden (depressive symptoms age 17: adjusted beta = 0.79; s.e. = 0.29; p = 0.01; suspected/definite PEs at age 12: adjusted OR = 1.60; 95% CI = 1.25-2.05). Childhood infections were not associated with depressive/psychotic outcomes at age 18 or 19.

CONCLUSIONS

Common early-childhood infections are associated with depressive symptoms up to mid-adolescence and with PEs subsequently in childhood, but not with these outcomes in early-adulthood. These findings require replication including larger samples with outcomes in adulthood.

Inflammation in Mental Disorders: Is the Microbiota the Missing Link?

Research suggests that inflammation is important in the pathophysiology of mental disorders. In addition, a growing body of evidence has led to the concept of the microbiota-gut-brain axis. To understand the potential interactions, we begin by exploring the liaison between the immune system and mental disorders, then we describe the evidence that the microbiota impact the immune response in the developing brain. Next, we review the literature that has documented microbiome alterations in major mental disorders. We end with a summary of therapeutic applications, ranging from psycho-biotics to immunomodulatory drugs that could affect the microbiota-gut-brain axis, and potential treatments to alleviate the adverse effects of antipsychotics. We conclude that there is promising evidence to support the position that the microbiota plays an important role in the immunological pathophysiology of mental disorders with an emphasis on psychotic disorders and mood disorders. However, more research is needed to elucidate the mechanisms.

Markers of Psychosis Risk in the General Population

The categorical approach to defining schizophrenia spectrum disorders requires meeting established criteria. To advance early identification and intervention in young people, the field has progressed to studying help-seeking individuals who are at clinical high risk based on subthreshold psychosis spectrum symptoms, and criteria have been articulated for qualifying individuals as at risk. A broader dimensional examination of psychosis has been applied to population-based studies on non-help seekers. This review highlights the ascertainment and assessment approaches to such population-based studies. Most studies are cross-sectional and rely on questionnaires with limited overlap of tools. However, several consistent findings emerge on symptoms, neurocognitive deficits, and neuroimaging parameters and other biomarkers associated with emergence and persistence of psychotic features. The findings are consistent with the literature on abnormalities associated with schizophrenia, including the presence of neurocognitive deficits; abnormalities in brain structure, function, and connectivity that are related to distress; impairment; and functional outcome. These findings support the validity of studying psychosis experiences during development in a way that can chart the emergence of psychosis in the context of general psychopathology. Such studies are necessary for establishing developmental trajectories that characterize this emergence and for identifying risk and resilience biomarkers moderating or modulating the full range of schizophrenia-related manifestations. More community-based studies are needed, with better standardization and harmonization of measures and incorporating longitudinal follow-up, to establish mechanistic links between cellular-molecular aberrations and specific manifestations of psychosis as envisioned by the precision medicine agenda.

A Review of Skin Disease in Schizophrenia

BACKGROUND

Schizophrenia is a debilitating neuropsychiatric condition that affects 0.5% of the North American population. Skin disease in schizophrenia has not been well described. Identifying skin diseases that are commonly comorbid with schizophrenia may help clinicians address the burden of skin disease in patients with schizophrenia.

SUMMARY

We conducted a nonsystematic review of the literature to identify skin diseases that may be associated with schizophrenia. We searched MEDLINE, EMBASE, and PsycINFO for articles published in English from December 2000 through April 2020 using the key words "skin disease" or "dermatological" or "dermatology" and "schizophrenia." Based on our results, we further refined the search terms to include more specific skin diseases. Schizophrenia appears to be associated with a number of skin diseases, including inflammatory dermatoses, autoimmune diseases, and certain genodermatoses. Limitations include being a nonsystematic review and the relative paucity of more rigorous clinical research using longitudinal study designs.

Bridging the Gap Between Physical Health and Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a highly complex and heterogeneous developmental disorder that affects how individuals communicate with other people and relate to the world around them. Research and clinical focus on the behavioural and cognitive manifestations of ASD, whilst important, have obscured the recognition that ASD is also commonly associated with a range of physical and mental health conditions. Many physical conditions appear with greater frequency in individuals with ASD compared to non-ASD populations. These can contribute to a worsening of social communication and behaviour, lower quality of life, higher morbidity and premature mortality. We highlight some of the key physical comorbidities affecting the immune and the gastrointestinal systems, metabolism and brain function in ASD. We discuss how healthcare professionals working with individuals with ASD and parents/carers have a duty to recognise their needs in order to improve their overall health and wellbeing, deliver equality in their healthcare experiences and reduce the likelihood of morbidity and early mortality associated with the condition.

Effects of early life adversity on immune function and cognitive performance: results from the ALSPAC cohort

BACKGROUND

Early life adversity (ELA) is a significant risk factor for mental health disorders. One hypothesised mechanism by which this occurs is via an effect on immune response. In this analysis of epidemiological data, we tested whether ELA was associated with cognitive performance, and if so, whether these effects were influenced by immune function.

METHODS

We investigated the longitudinal relationship between ELA, inflammatory markers, and cognition in data from Avon Longitudinal Study of Parents And Children (ALSPAC; n ~ 5000). ELA was defined in terms of physical/emotional abuse, harsh parenting, or domestic violence before 5 years. Social cognition was measured in terms of theory of mind, and general cognitive ability was measured using IQ. Inflammatory markers included serum C-reactive protein and interleukin-6 levels.

RESULTS

A significant association was observed between IQ and harsh parenting, whereby children who were physically disciplined had lower IQ scores (accounting for relevant social factors). Both immune markers were associated with variation in cognition, however, neither accounted for the effects of ELA on cognition.

DISCUSSION

This study highlights the impact of ELA on cognition. In the absence of evidence that these effects are explained by inflammation, other mechanisms by which the effects of ELA are mediated are discussed.

Neutrophil-lymphocyte ratio, monocyte-lymphocyte ratio and platelet-lymphocyte ratio in non-affective psychosis: A meta-analysis and systematic review

Objectives: Neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and monocyte/lymphocyte ratio (MLR) are inexpensive and reproducible biomarkers of inflammation. This is the first meta-analysis exploring the role of NLR, MLR and PLR in non-affective psychosis.Methods: Eight studies have been identified from the main electronic databases. Meta-analyses based on random-effects models have been carried out generating pooled standardised mean differences (SMDs) between non-affective psychotic patients and healthy controls (HCs).Results: Subjects with non-affective psychosis had a significant higher NLR and MLR as compared with HC (respectively SMD = 0.715; P < 0.001; I²=57.565% and SMD = 0.417; P = 0.001; I²=65.754%), confirmed by heterogeneity-based sensitivity analysis. Subgroup analyses showed no differences in effect size across different study characteristics, including drug treatment status, diagnosis, and setting. Meta-regression showed that age influenced the relationship between non-affective psychosis and MLR. A trend of significance, not confirmed by heterogeneity-based sensitivity analysis, was observed in PLR with patients showing higher PLR than HC.Conclusions: Our meta-analysis supports the hypothesis that an inflammatory activation occurs in non-affective psychosis and inflammatory ratios, especially NLR and MLR, may be useful to detect this activation.

Health Conditions and Psychotic Experiences: Cross-Sectional Findings From the American Life Panel

Background: People with psychotic disorders have poor health, but studies have shown that people who have a milder and more prevalent form of psychosis (psychotic experiences) are also at risk for health problems. More research is needed to examine a broad range of health conditions to discover new relations with psychotic experiences. Methods: We analyzed cross-sectional data from the American Life Panel, a nationally representative sample of the United States adult population. Using multivariable logistic regression, we examined the associations between health conditions (categories of conditions, specific conditions, count of conditions) and lifetime psychotic experiences. Results: Approximately 71% of the weighted sample reported at least one health condition, and around 18% reported a lifetime psychotic experience. Using multivariable logistic regression, we found that several health conditions were associated with psychotic experiences, including pain due to other causes, neck pain, other injury, any gastrointestinal/kidney problem, liver diseases/cirrhosis, any nervous/sensory problem, migraine, nerve problem causing numbness/pain, any other disorder, specifically sleep disorder, chronic fatigue syndrome, and chronic pain. Further, the count of specific health conditions and the count of categories were associated with greater odds of psychotic experiences. Conclusion: We found that numerous health conditions were associated with psychotic experiences.

Role of Infection, Autoimmunity, Atopic Disorders, and the Immune System in Schizophrenia: Evidence from Epidemiological and Genetic Studies

An immunologic component to schizophrenia has been increasingly recognized, where infections and chronic inflammatory diseases as atopic disorders and autoimmune diseases could be involved in the pathogenesis of schizophrenia. Psychotic symptoms can be directly triggered by infections reaching the CNS, or be secondary to systemic inflammation indirectly affecting the brain through immune components, such as brain-reactive antibodies and cytokines. Large-scale epidemiological studies have consistently displayed that infections, autoimmune diseases, and atopic disorders are associated with increased risk of schizophrenia and that schizophrenia is associated with increased levels of immune markers at diagnosis. However, since there is also an increased risk of immune-related diseases after the diagnosis with schizophrenia and in family members of individuals with schizophrenia, parts of the association could also be due to heritable factors. Shared genetic factor might account for some of this increased prevalence of immune-related diseases among individuals with schizophrenia, and indeed the most pronounced genetic association with schizophrenia lies within the HLA region, which is one of the most important regions for the immune system. However, genetic studies have shown that the common genetic variants associated with schizophrenia do not seem to increase the susceptibility for acquiring infections. Nonetheless, shared genes with the susceptibility for acquiring infections not captured by the polygenic risk score for schizophrenia could still influence the association.

Risk of Mental Disorders in Children and Adolescents With Atopic Dermatitis: A Systematic Review and Meta-Analysis

Assessing the psychological effects on children and adolescents of suffering atopic dermatitis (AD) is essential, when planning successful management. This study aimed to systematically review the literature regarding risk of mental disorders in children and adolescents with, or without, AD; and to explore confounders. We identified potentially relevant studies from EMBASE, MEDLINE, PsycINFO, ERIC, the British Nursing Index, the Family and Society Studies Worldwide, the Social Work Abstracts, and the Sociological Abstracts from inception to Sep 30, 2018. Investigators independently screened titles and abstracts, and then full-texts. Investigators independently extracted data from included studies. Meta-analyses using random-effects models were performed, reporting odds ratios (ORs; 95% CIs). Thirty-seven studies (n = 2,068,911 children/ adolescents) were included. Meta-analysis of 35 studies found that children and adolescents with AD had significantly higher risk of total mental disorders than those without AD (OR = 1.652; 95% CI, 1.463-1.864). There was no significant difference in risks for ADHD (OR = 1.563; 95% CI, 1.382-1.769); sleep disorders (OR = 2.100; 95% CI, 1.322-3.336); anxiety (OR = 1.339; 95% CI, 1.062-1.687); depression (OR = 1.402 95% CI, 1.256-1.565); conduct disorder (OR = 1.494 95% CI, 1.230-1.815); or ASD (OR = 2.574; 95% CI, 1.469-4.510; Q b = 8.344, p = 0.138). Race/ethnicity of child, target of comparison, type of studies, representativeness of the sample, measures of AD and mental disorders were significant moderators for total mental disorders. Integrated, holistic, multidisciplinary management of pediatric AD is significantly important, which emphasizes the well-being of the whole person.

Atopy Increases Risk of Psychotic Experiences: A Large Population-Based Study

Introduction: Building upon the comorbidity between atopy and schizophrenia, we conducted a large cross-sectional, observational population-based study to examine if such associations also exist between atopic disorders (eczema, allergic rhinitis, and asthma) and nonclinical psychotic experiences. Methods: We examined psychotic experiences in a Dutch population sample through an online survey (≥14 years of age). Participants filled out the Questionnaire for Psychotic Experiences, together with questions screening for atopic disorders (eczema, allergic rhinitis, and asthma). Prevalence rates were calculated; binary logistic regression was used to determine odds ratios (ORs) (age, gender, and years of education as covariates). Results: We included 6,479 participants. Individuals diagnosed with one or more atopic disorders had an increased risk of psychotic experiences as compared with controls (OR = 1.26). Analysis of individual symptoms revealed an OR of 1.27 for hallucinations, whereas delusions only showed a trend. With each additional atopic disorder, the risk of psychotic experiences increased. This was also observed for hallucinations alone but not for delusions alone. Atopy was associated with hallucinations across all modalities (OR ranging from 1.19 to 1.40). These results did not appear to be driven specifically by any one of the atopic disorders. Conclusion: In the largest population sample of adolescents and adults to date, we found that atopic disorders (asthma, eczema, and allergic rhinitis) increase the risk of psychotic experiences, in a dose-response fashion. These results provide further support for the role of immunological components in the predisposition for psychosis and can serve as a base for further research.

Peripheral Biomarkers for First-Episode Psychosis-Opportunities from the Neuroinflammatory Hypothesis of Schizophrenia

OBJECTIVE

Schizophrenia is a disabling disorder of unknown aetiology, lacking definite diagnostic method and cure. A reliable biological marker of schizophrenia is highly demanded, for which traceable immune mediators in blood could be promising candidates. We aimed to gather the best findings of neuroinflammatory markers for first-episode psychosis (FEP).

METHODS

We performed an extensive narrative review of online literature on inflammation-related markers found in human FEP patients only.

RESULTS

Changes to cytokine levels have been increasingly reported in schizophrenia. The peripheral levels of IL-1 (or its receptor antagonist), soluble IL-2 receptor, IL-4, IL-6, IL-8, and TNF-α have been frequently reported as increased in FEP, in a suggestive continuum from high-risk stages for psychosis. Microglia and astrocytes establish the link between this immune signalling and the synthesis of noxious tryptophan catabolism products, that cause structural damage and directly hamper normal neurotransmission. Amongst these, only 3-hydroxykynurenine has been consistently described in the blood of FEP patients.

CONCLUSION

Peripheral molecules stemming from brain inflammation might provide insightful biomarkers of schizophrenia, as early as FEP or even prodromal phases, although more time- and clinically-adjusted studies are essential for their validation.

Microglial Activation and Psychotic Disorders: Evidence from Pre-clinical and Clinical Studies

Clinical and pre-clinical studies have demonstrated an important role of neuroinflammation in the etiology of schizophrenia. While the underlying mechanisms remain poorly understood, there are some studies demonstrating an association between maternal immune activation and behavioral changes in adult offspring and identifying early life infection as a trigger for schizophrenia; in addition, inflammatory markers were found to be increased in the schizophrenic post-mortem brain. During maternal immune activation, pro-inflammatory mediators such as cytokines, chemokines, antibodies, and acute-phase proteins are released in the maternal bloodstream, thus increasing the permeability of the placental barrier and the fetal blood-brain barrier, allowing the inflammatory mediators to enter the fetal brain. In the central nervous system (CNS), these pro-inflammatory mediators are able to activate microglial cells that can release pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, and IL-6. As a consequence, circulating immune cells may infiltrate the brain, increasing cytokine levels and releasing antibodies that aggravate the neuroinflammation. Neuroinflammation may affect processes that are pivotal for normal brain maturation such as myelination, synaptic pruning, and neuronal remodeling. Microglial cell activation and pro-inflammatory mediators have been extensively studied in schizophrenic post-mortem brain samples. Some results of these investigations demonstrated an increase in microglial activation markers, cytokines, and chemokines in post-mortem brain samples from individuals with schizophrenia. In contrast, there are studies that have demonstrated low levels of microglial activation makers in the schizophrenic post-mortem brain. Thus, based on the important role of neuroinflammation as a trigger in the development of schizophrenia, this chapter aims (1) to enumerate evidence of neuroinflammation and microglial activation from pre-clinical schizophrenia models, (2) to show links between schizophrenia and neuroinflammation in clinical studies, and (3) to identify mechanisms by which microglial activation may influence in the development of schizophrenia.

Somatic comorbidity in children and adolescents with psychiatric disorders

In the adult population, psychiatric disorders are associated with somatic illness. Explanatory life style factors have been found, but also a failure to recognize somatic illness in this group. Another factor is side effects from long-term use of antipsychotic drugs. Given the psychiatric-somatic comorbidity in the adult population, it is of interest to investigate whether an association exists already during childhood. The aim of the present study was to investigate the frequency of somatic illness in children and adolescents with a psychiatric diagnose. Data were obtained from the regional health care database Vega, Sweden. Psychiatric and somatic diagnoses obtained during 2011-2013 for individuals aged 3-18 years were extracted. Descriptive statistics were used to examine difference in somatic morbidity between children with and without psychiatric diagnoses. Logistic regression was used in age-stratified models to test the association between psychiatric and somatic diagnoses. Anxiety and behavioral disorders were associated with all somatic conditions investigated at nearly all ages. The same applied to substance use, investigated at age 9-18 years. Affective disorders were associated with all somatic conditions at age 12-18 years. Psychotic conditions were associated with asthma, bowel disorders and myalgia in adolescents. Children with psychiatric disorders are at remarkably high risk for concurrent somatic illness. The associations span across many types of conditions and across all ages. The results support the need for awareness of somatic morbidity in child and adolescent psychiatric clinical settings, and the need for coordinated health care for children with comorbid states.

Psychotic experiences and general medical conditions: a cross-national analysis based on 28 002 respondents from 16 countries in the WHO World Mental Health Surveys

BACKGROUND

Previous work has identified associations between psychotic experiences (PEs) and general medical conditions (GMCs), but their temporal direction remains unclear as does the extent to which they are independent of comorbid mental disorders.

METHODS

In total, 28 002 adults in 16 countries from the WHO World Mental Health (WMH) Surveys were assessed for PEs, GMCs and 21 Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) mental disorders. Discrete-time survival analyses were used to estimate the associations between PEs and GMCs with various adjustments.

RESULTS

After adjustment for comorbid mental disorders, temporally prior PEs were significantly associated with subsequent onset of 8/12 GMCs (arthritis, back or neck pain, frequent or severe headache, other chronic pain, heart disease, high blood pressure, diabetes and peptic ulcer) with odds ratios (ORs) ranging from 1.3 [95% confidence interval (CI) 1.1-1.5] to 1.9 (95% CI 1.4-2.4). In contrast, only three GMCs (frequent or severe headache, other chronic pain and asthma) were significantly associated with subsequent onset of PEs after adjustment for comorbid GMCs and mental disorders, with ORs ranging from 1.5 (95% CI 1.2-1.9) to 1.7 (95% CI 1.2-2.4).

CONCLUSIONS

PEs were associated with the subsequent onset of a wide range of GMCs, independent of comorbid mental disorders. There were also associations between some medical conditions (particularly those involving chronic pain) and subsequent PEs. Although these findings will need to be confirmed in prospective studies, clinicians should be aware that psychotic symptoms may be risk markers for a wide range of adverse health outcomes. Whether PEs are causal risk factors will require further research.

Major Comorbidities of Atopic Dermatitis: Beyond Allergic Disorders

The consequences of atopic dermatitis reach beyond the skin and past childhood. Patients with atopic dermatitis are at risk of developing allergic comorbidities, but less is known about the associations between atopic dermatitis and non-allergic conditions. Understanding these non-allergic comorbidities has the potential to improve patient outcomes and to help mitigate the cost and burdens associated with these conditions. Atopic dermatitis is associated with cutaneous bacterial infections, more severe forms/courses of cutaneous viral infections, and extra-cutaneous infections. Atopic dermatitis is also associated with several mental health comorbidities particularly attention-deficit hyperactivity disorder, anxiety, and depression. Data are largely inconsistent for specific cancers, but atopic dermatitis appears to protect against malignancy overall; severe long-term atopic dermatitis is associated with adult lymphomas. Atopic dermatitis may also be associated with obesity, cardiovascular disease, and autoimmune disease, particularly alopecia areata and gastrointestinal immune-mediated disorders. Although the causative mechanisms underlying these associations are poorly understood, treating physicians should be aware of associations in seeking to alleviate the burden for patients with atopic dermatitis.

Childhood inflammatory markers and intelligence as predictors of subsequent persistent depressive symptoms: a longitudinal cohort study

BACKGROUND

To identify developmental sub-groups of depressive symptoms during the second decade of life, a critical period of brain development, using data from a prospective birth cohort. To test whether childhood intelligence and inflammatory markers are associated with subsequent persistent depressive symptoms.

METHODS

IQ, a proxy for neurodevelopment, was measured at age 8 years. Interleukin 6 (IL-6) and C-reactive protein, typical inflammatory markers, were measured at age 9 years. Depressive symptoms were measured six times between 10 and 19 years using the short mood and feelings questionnaire (SMFQ), which were coded as binary variable and then used in latent class analysis to identify developmental sub-groups of depressive symptoms.

RESULTS

Longitudinal SMFQ data from 9156 participants yielded three distinct population sub-groups of depressive symptoms: no symptoms (81.2%); adolescent-onset symptoms (13.2%); persistent symptoms (5.6%). Lower IQ and higher IL-6 levels in childhood were independently associated with subsequent persistent depressive symptoms in a linear, dose-response fashion, but not with adolescent-onset symptoms. Compared with the group with no symptoms the adjusted odds ratio for persistent depressive symptoms per s.d. increase in IQ was 0.80 (95% CI, 0.68-0.95); that for IL-6 was 1.20 (95% CI, 1.03-1.39). Evidence for an association with IL-6 remained after controlling for initial severity of depressive symptoms at 10 years. There was no evidence that IL-6 moderated or mediated the IQ-persistent depressive symptom relationship.

CONCLUSIONS

The results indicate potentially important roles for two distinct biological processes, neurodevelopment and inflammation, in the aetiology of persistent depressive symptoms in young people.

Clonal Characteristics of T-Cell Receptor Repertoires in Violent and Non-violent Patients With Schizophrenia

Background: Activated or impaired T-cell function in inflammatory and degenerative process can contribute to the risk and progression of schizophrenia. This study used immune repertoire sequencing to investigate the T-cell receptor beta variable chain (TRBV) presence in blood mononuclear cells in the violent or non-violent schizophrenic patients. Methods: Ten violent and 10 non-violent schizophrenic patients and 8 matched healthy controls were enrolled. The Brief Psychiatric Rating Scale (BPRS) was used to evaluate patients' psychiatric symptoms. The level of aggression was assessed using the Modified Overt Aggression Scale (MOAS). The complementarity-determining region 3 (CDR3) of TRBV was detected using multiplex-PCR and high-throughput sequencing. Results: The TCR repertoire diversity were no significant differences in the Shannon-Wiener or inverse Simpson diversity index between three groups. Principal component analysis (PCA) of TRBV composition and abundance showed that principal component 1 and principal component 2 can explain 28.88 and 13.24% of total variation, respectively. Schizophrenic patients (violent and non-violent) had significantly different V gene distribution compared to healthy controls. In particular, TRBV2 occurred at a significantly higher frequency in the violent schizophrenia group than in the non-violent schizophrenia and healthy control groups, and TRBV7-2 occurred at a significantly higher frequency in the non-violent schizophrenia group than in the violent schizophrenia and healthy control groups. Conclusions: The results suggest that violent and non-violent schizophrenic patients carry abnormal T-cell receptor repertoires, and these data provide a useful clue to explore the etiology of violent behavior in schizophrenia.

Protein-C Reactive as Biomarker Predictor of Schizophrenia Phases of Illness? A Systematic Review

BACKGROUND

Schizophrenia is a complex illness in which genetic, environmental, and epigenetic components have been implicated. However, recently, psychiatric disorders appear to be related to a chronic inflammatory state, at the level of specific cerebral areas which have been found as well impaired and responsible for schizophrenia symptomatology. Hence, a role of inflammatory mediators and cytokines has been as well defined. Accordingly, the role of an acute inflammatory phase protein, the C-reactive protein (CRP) has been recently investigated.

OBJECTIVE

The objective of the present study is to evaluate how PCR may represent a biomarker in schizophrenia, i.e. correlated with illness phases and/or clinical manifestation and/or psychopathological severity.

METHODS

A systematic review was here carried out by searching the following keywords ((C-reactive protein AND ((schizophrenia) OR (psychotic disorder))) for the topics 'PCR' and 'Schizophrenia', by using MESH terms.

RESULTS

An immune dysfunction and inflammation have been described amongst schizophrenic patients. Findings reported elevated CRP levels in schizophrenia, mainly correlated with the severity of illness and during the recrudescent phase. CRP levels are higher when catatonic features, negative symptomatology and aggressiveness are associated. CRP levels appeared not to be related to suicidal behaviour and ideation.

CONCLUSION

CRP and its blood levels have been reported higher amongst schizophrenic patients, by suggesting a role of inflammation in the pathogenesis of schizophrenia. Further studies are needed to better understand if CRP may be considered a biomarker in schizophrenia.

Immunopsychiatry: important facts

Accumulating evidence indicate a role for the immune system particularly inflammation and autoimmunity in the aetiology of major psychiatric disorders such as depression and schizophrenia. In this paper, we discuss some of the key advances in immunopsychiatry in order to highlight to psychiatrists and other health professionals how an increased understanding of this field might enhance our knowledge of illness mechanism and approaches to treatment. We present a brief overview of clinical research that link inflammation and autoimmunity with depression and psychosis, including potential role of inflammation in treatment response, current evidence for the effectiveness of immune-modulating treatment for depression and psychosis, and possible role of inflammation in common physical comorbidities for these disorders such as coronary heart disease and diabetes mellitus. Gaining a better understanding of the role of immune system could be paradigm changing for psychiatry. We need collaborations between clinicians and scientists to deliver high-quality translational research in order to fully realise the clinical potential of this exciting and rapidly expanding field.

Use of glucocorticoids during pregnancy and risk of attention-deficit/hyperactivity disorder in offspring: a nationwide Danish cohort study

OBJECTIVE

Prenatal exposure to excess endogenous glucocorticoid (GC) has been linked to attention-deficit/hyperactivity disorder (ADHD). We investigated whether prenatal exposure to exogenous GC is associated with ADHD.

DESIGN

Nationwide cohort study.

SETTING

A cohort of 875 996 singletons born alive between 1996 and 2009 in Denmark. Data were obtained from national registries.

EXPOSURES

We identified children exposed prenatally to GCs, children unexposed prenatally and born to maternal former users, and children unexposed and born to maternal never users.

MAIN OUTCOME MEASURES

We compared ADHD risk in children prenatally exposed to GCs and in children of former GC users with risk in unexposed children of never users. We computed cumulative incidence at 10 years of age and adjusted HRs (aHRs). In addition, we compared exposed children with unexposed siblings in a sibling design.

RESULTS

We identified 875 996 children, among whom 5319 were prenatally exposed to systemic GCs and 36 780 to local/inhaled GCs. Cumulative incidences of ADHD at 10 years of age were 2.65% in prenatally exposed children and 2.03% in unexposed children of never users. At the general population level, prenatal exposure was associated with ADHD compared with unexposed, with aHR of 1.43(95% CI 1.24 to 1.65) for systemic exposure and 1.23 (95% CI 1.15 to 1.31) for local/inhaled exposure. However, our former user analysis (aHR of 1.25 (95% CI 1.20 to 1.29)) and sibling design (aHR of 1.03 (95% CI 0.87 to 1.20)) indicated that these findings were due to confounding.

CONCLUSION

This study provides no evidence of a causal association between prenatal exposure to GCs and risk of ADHD.

A Survey of Pediatric Acute-Onset Neuropsychiatric Syndrome Characteristics and Course

OBJECTIVE

To date, studies in the area of pediatric acute-onset neuropsychiatric syndrome (PANS; including pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection [PANDAS] and pediatric infection-triggered neuropsychiatric disorder [PITAND]) have been relatively small and hence unable to comprehensively address questions of disease heterogeneity (e.g., by age, gender), comorbidities, and progression. In this study, we investigated an internet survey sample to more fully characterize the phenotypic traits; medical, family, and developmental history; functional challenges; and clinical course associated with PANS.

METHODS

Six hundred and ninety-eight patients with clinical diagnoses of PANS were included in this study. Participants, who included parents and legal guardians (for minors) or the PANS patients themselves (for those ages 18 and older), were asked to complete a 146-question survey designed to ascertain medical, developmental, and family history; PANS symptomatology; medical and nonmedical interventions for PANS; PANS course; PANS outcomes; and access to PANS care.

RESULTS

Our results agree with previous findings concerning the core symptoms of PANS as well as its male predominance (65% in this survey) and infection-triggered onset, thus validating the study population. Infection was implicated as the primary inciting factor in 65% of patients; 54% of patients reported an association with group A streptococcus specifically. The results of this survey also revealed new findings, including a surprisingly strong impact of gender and pubertal status on symptom course and chronicity, a high rate of medical comorbidity suggesting generalized immune dysfunction, a profound impact of PANS episodes on functional status, and a role for early resolution of infection through antibiotic treatment in disease course.

CONCLUSIONS

This study serves as the first survey of its size to provide insight into the global clinical picture and range of phenotypes of PANS patients. Significant results included the impact of gender and pubertal status on phenotype, affirmation of the role of the immune system in PANS pathology, and the role of timely resolution of infection in clinical outcomes. Understanding how PANS presents in a broad population-based sample, within the limitations of a self-selected and administered online survey, is an important step toward improving diagnosis, creating more targeted treatment options, educating the clinical and research community, and generating hypotheses for future prospective research.

Medical Co-morbidities Among Patients with Severe Mental Illnesses in a Community Health Facility in Nigeria

To examine prevalence of medical comorbidity (MCM) in schizophrenia (n = 1310) and in bipolar disorder (n = 1307) and the association of high burden of MCM (≥3 MCM) with duration of untreated illness, number of episodes, functioning, poly-medication and lifetime hospitalization for the mental disorder. Participants were recruited from a private psychiatric facility in Ibadan, Nigeria between 2004 and 2013 and enquiry made about the lifetime occurrence of 20 common chronic diseases including common tropical diseases. Psychiatric diagnosis was made using the Structured Clinical Interview for DSM IV Axis I disorder (SCID). Except for nutritional anemia, dermatitis and intestinal Helminthiasis, patients with schizophrenia were not at higher odds of reporting MCM than those with bipolar disorder. DUI ≥2 years, episodes of illness ≥3, being on multiple neuroleptics and history of previous hospitalization were significantly associated with high burden of MCM in schizophrenia and episodes of illness ≥3, reduced functioning and history of previous hospitalization with bipolar disorder. Schizophrenia and bipolar disorder are associated with high rates of medical comorbidity. Treatment of this medical comorbidity is essential in order to improve the outcomes for patients with bipolar disorder and schizophrenia.

Inflammation, Stress Response, and Redox Dysregulation Biomarkers: Clinical Outcomes and Pharmacological Implications for Psychosis

In recent years, several studies claiming the finding of a specific biomarker for the identification of the "high-risk state" to develop psychosis, first psychotic episode, as well as the prediction of the individual response to antipsychotics have been published. Together with genetic reports, numerous publications in this field have been focused on inflammation and stress response blood biomarkers, as well as on indicators of redox dysregulation. In this review, we focus on human studies found in PubMed from January 1^st 2010 to January 31^st 2017, describing the clinical use of these biomarkers to detect the "premorbid" psychotic state and early phases of the disease. Their pharmacological implications in predicting and monitoring the individual response to antipsychotic medication is also discussed.

Childhood interleukin-6, C-reactive protein and atopic disorders as risk factors for hypomanic symptoms in young adulthood: a longitudinal birth cohort study

BACKGROUND

There are no existing longitudinal studies of inflammatory markers and atopic disorders in childhood and risk of hypomanic symptoms in adulthood. This study examined if childhood: (1) serum interleukin-6 (IL-6) and C-reactive protein (CRP); and (2) asthma and/or eczema are associated with features of hypomania in young adulthood.

METHOD

Participants in the Avon Longitudinal Study of Parents and Children, a prospective general population UK birth cohort, had non-fasting blood samples for IL-6 and CRP measurement at the age of 9 years (n = 4645), and parents answered a question about doctor-diagnosed atopic illness before the age of 10 years (n = 7809). These participants completed the Hypomania Checklist at age 22 years (n = 3361).

RESULTS

After adjusting for age, sex, ethnicity, socio-economic status, past psychological and behavioural problems, body mass index and maternal postnatal depression, participants in the top third of IL-6 values at 9 years, compared with the bottom third, had an increased risk of hypomanic symptoms by age 22 years [adjusted odds ratio 1.77, 95% confidence interval (CI) 1.10-2.85, p < 0.001]. Higher IL-6 levels in childhood were associated with adult hypomania features in a dose-response fashion. After further adjustment for depression at the age of 18 years this association remained (adjusted odds ratio 1.70, 95% CI 1.03-2.81, p = 0.038). There was no evidence of an association of hypomanic symptoms with CRP levels, asthma or eczema in childhood.

CONCLUSIONS

Higher levels of systemic inflammatory marker IL-6 in childhood were associated with hypomanic symptoms in young adulthood, suggesting that inflammation may play a role in the pathophysiology of mania. Inflammatory pathways may be suitable targets for the prevention and intervention for bipolar disorder.

Serum C-reactive protein in adolescence and risk of schizophrenia in adulthood: A prospective birth cohort study

OBJECTIVE

Meta-analyses of cross-sectional studies confirm an increase in circulating inflammatory markers during acute psychosis. Longitudinal studies are scarce but are needed to understand whether elevated inflammatory markers are a cause or consequence of illness. We report a longitudinal study of serum C-reactive protein (CRP) in adolescence and subsequent risk of schizophrenia and related psychoses in adulthood in the Northern Finland Birth Cohort 1986.

METHOD

Serum high-sensitivity CRP was measured at age 15/16 years in 6362 participants. ICD-10 diagnoses of schizophrenia and related psychoses were obtained from centralised hospital inpatient and outpatient registers up to age 27 years. Logistic regression calculated odds ratios (ORs) for psychotic outcomes associated with baseline CRP levels analysed as both continuous and categorical variables using American Heart Association criteria. Age, sex, body mass index, maternal education, smoking, and alcohol use were included as potential confounders.

RESULTS

By age 27years, 88 cases of non-affective psychosis (1.38%), of which 22 were schizophrenia (0.35%), were identified. Adolescent CRP was associated with subsequent schizophrenia. The adjusted OR for schizophrenia by age 27yearsfor each standard deviation (SD) increase in CRP levels at age 15/16yearswas 1.25 (95% CI, 1.07-1.46), which was consistent with a linear, dose-response relationship (P-value for quadratic term 0.23). Using CRP as a categorical variable, those with high (>3mg/L) compared with low (<1mg/L) CRP levels at baseline were more likely to develop schizophrenia; adjusted OR 4.25 (95% CI, 1.30-13.93). There was some indication that higher CRP was associated with earlier onset of schizophrenia (rs=-0.40; P=0.07).

CONCLUSIONS

A longitudinal association between adolescent CRP levels and adult schizophrenia diagnosis indicates a potentially important role of inflammation in the pathogenesis of the illness, although the findings, based on a small number of cases, need to be interpreted with caution and require replication in other samples.

Infectious, atopic and inflammatory diseases, childhood adversities and familial aggregation are independently associated with the risk for mental disorders: Results from a large Swiss epidemiological study

AIM

To examine the associations between mental disorders and infectious, atopic, inflammatory diseases while adjusting for other risk factors.

METHODS

We used data from PsyCoLaus, a large Swiss Population Cohort Study (n = 3720; age range 35-66). Lifetime diagnoses of mental disorders were grouped into the following categories: Neurodevelopmental, anxiety (early and late onset), mood and substance disorders. They were regressed on infectious, atopic and other inflammatory diseases adjusting for sex, educational level, familial aggregation, childhood adversities and traumatic experiences in childhood. A multivariate logistic regression was applied to each group of disorders. In a complementary analysis interactions with sex were introduced via nested effects.

RESULTS

Associations with infectious, atopic and other chronic inflammatory diseases were observable together with consistent effects of childhood adversities and familial aggregation, and less consistent effects of trauma in each group of mental disorders. Streptococcal infections were associated with neurodevelopmental disorders (men), and measles/mumps/rubella-infections with early and late anxiety disorders (women). Gastric inflammatory diseases took effect in mood disorders (both sexes) and in early disorders (men). Similarly, irritable bowel syndrome was prominent in a sex-specific way in mood disorders in women, and, moreover, was associated with early and late anxiety disorders. Atopic diseases were associated with late anxiety disorders. Acne (associations with mood disorders in men) and psoriasis (associations with early anxiety disorders in men and mood disorders in women) contributed sex-specific results. Urinary tract infections were associated with mood disorders and, in addition, in a sex-specific way with late anxiety disorders (men), and neurodevelopmental and early anxiety disorders (women).

CONCLUSION

Infectious, atopic and inflammatory diseases are important risk factors for all groups of mental disorders. The sexual dimorphism of the associations is pronounced.

C-reactive protein concentrations across the mood spectrum in bipolar disorder: a systematic review and meta-analysis

BACKGROUND

Inflammatory processes and neural-immune interactions have been implicated in the pathogenesis of psychiatric conditions, but studies in bipolar disorder are inconclusive so far. We aimed to investigate whether peripheral concentrations of C-reactive protein (CRP), an acute-phase response protein of inflammatory activity, are increased in bipolar disorder across the mood spectrum.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE, the Cochrane Library, Scopus, and Web of Knowledge from database inception to Aug 14, 2016, for studies that measured serum and plasma CRP concentrations in adult patients with bipolar disorder (as defined by DSM-IV-TR) and healthy controls. We extracted data from published reports. We did three between-group meta-analyses comparing CRP concentrations in patients in mania, depression, or euthymia, with those in healthy controls (cross-sectional studies), and two within-group meta-analyses comparing changes in CRP concentrations before and after treatment of an index manic or depressive episode (longitudinal studies). We used Hedges' adjusted g to calculate effect sizes and pooled results using random-effect models. We also did meta-regression analyses by mood state to investigate possible moderators of CRP concentrations.

FINDINGS

We identified 27 studies representing 2161 patients with bipolar disorder and 81 932 healthy controls. Compared with healthy individuals, CRP concentrations were moderately increased in people with bipolar disorder during depression (g 0·67, 95% CI 0·23 to 1·11; p=0·003) and euthymia (0·65, 0·40 to 0·90; p<0·0001) and more substantially increased during mania (0·87, 0·58 to 1·15; p<0·0001). The extent of the increases in CRP concentrations in mania and depression was not related to symptom severity (p=0·256 for mania and p=0·626 for depression). CRP concentrations were moderately decreased after resolution of an index manic episode (-0·36, -0·66 to -0·05; p=0·022) and slightly decreased after resolution of an index depressive episode (-0·18, -0·30 to -0·07; p=0·002).

INTERPRETATION

CRP concentrations are increased in bipolar disorder regardless of mood state, but are higher during mania than in depression and euthymia, suggesting an increased inflammatory burden in mania.

FUNDING

None.

Functional Implications of the IL-23/IL-17 Immune Axis in Schizophrenia

The aetiology of schizophrenia seems to stem from complex interactions amongst environmental, genetic, metabolic, immunologic and oxidative components. Chronic low-grade inflammation has been persistently linked to schizophrenia, and this has primarily been based on the findings derived from Th1/Th2 cytokine balance. While the IL-23/IL-17 axis plays crucial role in the pathogenesis of several immune-mediated disorders, it has remained relatively unexplored in neuropsychiatric disorders. Altered levels of cytokines related to IL-23/IL-17 axis have been observed in schizophrenia patients in a few studies. In addition, other indirect factors known to confer schizophrenia risk like complement activation and altered gut microbiota are shown to modulate the IL-23/IL-17 axis. These preliminary observations provide crucial clues about the functional implications of IL-23/IL-17 axis in schizophrenia. In this review, an attempt has been made to highlight the biology of IL-23/IL-17 axis and its relevance to schizophrenia risk and pathogenesis. Given the pathogenic potential of the IL-23/IL-17 axis, therapeutic targeting of this axis may be a promising approach to benefit patients suffering from this devastating disorder.

Stratum Corneum Tape Stripping: Monitoring of Inflammatory Mediators in Atopic Dermatitis Patients Using Topical Therapy

OBJECTIVE

The aim of this study was to explore the tape strip sampling technique in the assessment of stratum corneum levels of inflammatory mediators in a clinical trial setting.

METHODS

Thirty-eight inflammatory mediators were analyzed by a multiplex-assay in the stratum corneum, collected by adhesive tapes before and after 6 weeks of therapy, in mild and moderate atopic dermatitis (AD) patients (n = 90). Treatment was a ceramide- and magnesium-containing emollient.

RESULTS

Twenty-four mediators could quantitatively be determined. The Th2 mediators interleukin (IL)-4, IL-13, CCL2 (monocyte chemotactic protein-1), CCL22 (macrophage-derived chemokine), and CCL17 [thymus and activation-regulated chemokine (TARC)] were significantly decreased after therapy as well as IL-1β, IL-2, IL-8 (CXCL8), IL-10, acute-phase protein serum amyloid A, C-reactive protein, and vascular adhesion molecule-1. The decrease of CCL17 and IL-8 was correlated with the decrease in disease severity in a subgroup of moderate AD individuals.

CONCLUSION

Stratum corneum tape stripping offers a minimally invasive approach for studying local levels of immunomodulatory molecules in the skin. CCL17 (TARC) and IL-8 were found to be the most promising biomarkers of AD and might be useful for investigating the course of skin diseases and the effect of local therapy.

Clinical studies of neuroinflammatory mechanisms in schizophrenia

Schizophrenia is a pervasive neurodevelopmental disorder that appears to result from genetic and environmental factors. Although the dopamine hypothesis is the driving theory behind the majority of translation research in schizophrenia, emerging evidence suggests that aberrant immune mechanisms in the peripheral and central nervous system influence the etiology of schizophrenia and the pathophysiology of psychotic symptoms that define the illness. The initial interest in inflammatory processes comes from epidemiological data and historical observations, dating back several decades. A growing body of research on developmental exposure to infection, stress-induced inflammatory response, glial cell signaling, structural and functional brain changes and therapeutic trials demonstrates the impact that inflammation has on the onset and progression of schizophrenia. Research in animal models of psychosis has helped to advance clinical and basic science investigations of the immune mechanisms disrupted in schizophrenia. However, they are limited by the inability to recapitulate the human experience of hallucinations, delusions and thought disorder that define psychosis. To date, translational studies of inflammatory mechanisms in human subjects have not been reviewed in great detail. Here, we critically review clinical studies that focus on inflammatory mechanisms in schizophrenia. Understanding the neuroinflammatory mechanisms involved in schizophrenia may be essential in identifying potential therapeutic targets to minimize the morbidity and mortality of schizophrenia by interrupting disease development.

Higher Plasma S100B Concentrations in Schizophrenia Patients, and Dependently Associated with Inflammatory Markers

Glial damage and immune dysfunction are involved in pathogenesis of schizophrenia. However, interaction between glial damage and immune dysfunction in schizophrenia is undefined. This study aims to compare plasma S100 calcium binding protein (S100B) levels between schizophrenia patients and healthy participants, and to determine if immune markers are independently related with concentration of S100B in schizophrenia patients. Forty-one schizophrenia patients and thirty-three healthy volunteers were enrolled. Enzyme-linked immunosorbent assay (ELISA) was used to assess the concentrations of plasma S100B and inflammatory markers. We found that concentrations of S100B were elevated in schizophrenia patients than healthy participants (p < 0.05), and were negatively related with the severity of symptoms (p = 0.046). Receiver operating characteristic (ROC) curve analysis showed that different S100B levels between schizophrenia and healthy participants can be used as a clinical diagnostic factor (predictive value: 0.666, p = 0.015). Multiple linear regression analysis found that length of illness (Beta = −0.161), plasma levels of inflammatory regulation factors (including TGF-β1, logIL-23 and logIL-10) (Beta = 0.119, 0.475, 0.514) were independently associated with concentrations of S100B (Adjusted R² = 0.897, p < 0.001). Therefore, our results suggest the possible function of S100B in pathogenesis of schizophrenia, and implicate the important role of autoimmune response and balance to glial dysfunction in patients with schizophrenia.

Is there a role for immune-to-brain communication in schizophrenia?

Schizophrenia is characterised by hallucinations, delusions, depression-like so-called negative symptoms, cognitive dysfunction, impaired neurodevelopment and neurodegeneration. Epidemiological and genetic studies strongly indicate a role of inflammation and immunity in the pathogenesis of symptoms of schizophrenia. Evidence accrued over the last two decades has demonstrated that there are a number of pathways through which systemic inflammation can exert profound influence on the brain leading to changes in mood, cognition and behaviour. The peripheral immune system-to-brain communication pathways have been studied extensively in the context of depression where inflammatory cytokines are thought to play a key role. In this review, we highlight novel evidence suggesting an important role of peripheral immune-to-brain communication pathways in schizophrenia. We discuss recent population-based longitudinal studies that report an association between elevated levels of circulating inflammatory cytokines and subsequent risk of psychosis. We discuss emerging evidence indicating potentially important role of blood-brain barrier endothelial cells in peripheral immune-to-brain communication, which may be also relevant for schizophrenia. Drawing on clinical and preclinical studies, we discuss whether immune-mediated mechanisms could help to explain some of the clinical and pathophysiological features of schizophrenia. We discuss implication of these findings for approaches to diagnosis, treatment and research in future. Finally, pointing towards links with early-life adversity, we consider whether persistent low-grade activation of the innate immune response, as a result of impaired foetal or childhood development, could be a common mechanism underlying the high comorbidity between certain neuropsychiatric and physical illnesses, such as schizophrenia, depression, heart disease and type-two diabetes.

Is there a role for immune-to-brain communication in schizophrenia?

Schizophrenia is characterised by hallucinations, delusions, depression-like so-called negative symptoms, cognitive dysfunction, impaired neurodevelopment and neurodegeneration. Epidemiological and genetic studies strongly indicate a role of inflammation and immunity in the pathogenesis of symptoms of schizophrenia. Evidence accrued over the last two decades has demonstrated that there are a number of pathways through which systemic inflammation can exert profound influence on the brain leading to changes in mood, cognition and behaviour. The peripheral immune system-to-brain communication pathways have been studied extensively in the context of depression where inflammatory cytokines are thought to play a key role. In this review, we highlight novel evidence suggesting an important role of peripheral immune-to-brain communication pathways in schizophrenia. We discuss recent population-based longitudinal studies that report an association between elevated levels of circulating inflammatory cytokines and subsequent risk of psychosis. We discuss emerging evidence indicating potentially important role of blood-brain barrier endothelial cells in peripheral immune-to-brain communication, which may be also relevant for schizophrenia. Drawing on clinical and preclinical studies, we discuss whether immune-mediated mechanisms could help to explain some of the clinical and pathophysiological features of schizophrenia. We discuss implication of these findings for approaches to diagnosis, treatment and research in future. Finally, pointing towards links with early-life adversity, we consider whether persistent low-grade activation of the innate immune response, as a result of impaired foetal or childhood development, could be a common mechanism underlying the high comorbidity between certain neuropsychiatric and physical illnesses, such as schizophrenia, depression, heart disease and type-two diabetes.

Comorbidity of Atopic Disorders with Autism Spectrum Disorder and Attention Deficit/Hyperactivity Disorder

OBJECTIVE

To assess the relationship between allergic manifestations in early life and the occurrence of newly diagnosed autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) throughout childhood.

STUDY DESIGN

We collected a population-based longitudinal cohort comprising children enrolled in Taiwan's National Health Insurance Program during 2000-2010. We first identified 387,262 children who had a diagnosis of atopic dermatitis (AD) before age 2 years, with 1:1 individualized matching to children without AD. Cox regression analyses were performed to estimate the early-onset and cumulative effects of allergic manifestations on ASD and ADHD.

RESULTS

An estimated 0.5% of AD-exposed children received a diagnosis of ASD, and 3.7% were diagnosed with ADHD, significantly higher than the respective rates of 0.4% and 2.9% found in their nonexposed peers. Having AD before age 2 years was associated with an increased hazard ratio (HR) for ASD by 10% and that for ADHD by 16%; such increases were particularly prominent among those with earlier-onset or more severe AD. HRs were especially higher for children with persistent AD and emerging atopic respiratory diseases in childhood (eg, for ASD, adjusted HR, 1.75 and 2.13, respectively; P < .001).

CONCLUSION

The observed increased risks of ASD and ADHD associated with AD in infancy suggest that a disordered immunologic response may exert effects on neurodevelopment and have implications for research into etiology and treatment strategies.

The Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort as a resource for studying psychopathology in childhood and adolescence: a summary of findings for depression and psychosis

PURPOSE

The purpose of this study is to highlight the Avon Longitudinal Study of Parents and Children (ALSPAC) as a resource to study psychopathology. To demonstrate this, we review the studies related to depression and psychosis in childhood and adolescence and discuss the results in relation to the aetiology of depression and psychotic experiences (PEs) and possible underlying mechanisms.

METHODS

We examined the list of publications from ALSPAC and then classified them as examining (a) the course and risk factors of maternal and paternal depression, (b) the effects of maternal and paternal depression on child development, (c) risk factors for depression in childhood and adolescence, (d) the frequency, clinical relevance and risk factors of PEs, and (e) shared risk factors for depression and PEs.

RESULTS

There was evidence that environmental stressors and the way these are interpreted contribute to risk of depression and evidence that biological factors related to puberty are also likely to play a role. With regards to PEs, the findings further support the existence of 'a continuum of psychosis' while they also suggest that PEs might be of limited clinical utility in predicting psychotic disorder during adolescence and early adulthood. Finally, most risk factors examined were found to be shared between depression and PEs.

CONCLUSIONS

The ALSPAC birth cohort has provided important insights for our understanding of the aetiological mechanisms underlying depression and PEs. Future research could aim to incorporate measures of automatic psychological mechanisms to provide insights into the brain mechanisms that underlie these clinical phenomena.

Is childhood cat ownership a risk factor for schizophrenia later in life?

Two previous studies suggested that childhood cat ownership is a possible risk factor for later developing schizophrenia or other serious mental illness. We therefore used an earlier, large NAMI questionnaire to try and replicate this finding. The results were the same, suggesting that cat ownership in childhood is significantly more common in families in which the child later becomes seriously mentally ill. If true, an explanatory mechanism may be Toxoplasma gondii. We urge our colleagues to try and replicate these findings to clarify whether childhood cat ownership is truly a risk factor for later schizophrenia.

Inflammation and immunity in schizophrenia: implications for pathophysiology and treatment

Complex interactions between the immune system and the brain might have important aetiological and therapeutic implications for neuropsychiatric brain disorders. A possible association between schizophrenia and the immune system was postulated over a century ago, and is supported by epidemiological and genetic studies pointing to links with infection and inflammation. Contrary to the traditional view that the brain is an immunologically privileged site shielded behind the blood-brain barrier, studies in the past 20 years have noted complex interactions between the immune system, systemic inflammation, and the brain, which can lead to changes in mood, cognition, and behaviour. In this Review, we describe some of the important areas of research regarding innate and adaptive immune response in schizophrenia and related psychotic disorders that, we think, will be of interest to psychiatric clinicians and researchers. We discuss potential mechanisms and therapeutic implications of these findings, including studies of anti-inflammatory drugs in schizophrenia, describe areas for development, and offer testable hypotheses for future investigations.

A population-based longitudinal study of childhood neurodevelopmental disorders, IQ and subsequent risk of psychotic experiences in adolescence

BACKGROUND

Schizophrenia has a neurodevelopmental component to its origin, and may share overlapping pathogenic mechanisms with childhood neurodevelopmental disorders (NDs). Nevertheless, longitudinal studies of psychotic outcomes among individuals with NDs are limited. We report a population-based prospective study of six common childhood NDs, subsequent neurocognitive performance and the risk of psychotic experiences (PEs) in early adolescence.

METHOD

PEs were assessed by semi-structured interviews at age 13 years. IQ and working memory were measured between ages 9 and 11 years. The presence of six NDs (autism spectrum, dyslexia, dyspraxia, dysgraphia, dysorthographia, dyscalculia) was determined from parent-completed questionnaires at age 9 years. Linear regression calculated the mean difference in cognitive scores between children with and without NDs. Associations between NDs and PEs were expressed as odds ratios (ORs) with 95% confidence intervals (CIs); effects of cognitive deficits were examined. Potential confounders included age, gender, father's social class, ethnicity and maternal education.

RESULTS

Out of 8220 children, 487 (5.9%) were reported to have NDs at age 9 years. Children with, compared with those without, NDs performed worse on all cognitive measures; the adjusted mean difference in total IQ was 6.84 (95% CI 5.00-8.69). The association between total IQ and NDs was linear (p < 0.0001). The risk of PEs was higher in those with, compared with those without, NDs; the adjusted OR for definite PEs was 1.76 (95% CI 1.11-2.79). IQ (but not working memory) deficit partly explained this association.

CONCLUSIONS

Higher risk of PEs in early adolescence among individuals with childhood ND is consistent with the neurodevelopmental hypothesis of schizophrenia.