Is schizophrenia a neurodevelopmental disorder?

Adolescent schizophrenia

Schizophrenia is a devastating chronic disorder that typically presents in early adult life and impacts on a broad swathe of social and psychological functioning. It is not surprising that psychiatrists have tended to be circumspect about making this ominous diagnosis in children and adolescents. Genuine concerns about the validity of applying ‘adult’ psychotic diagnoses in this young age group, together with the lack of diagnosis-specific interventions, have suggested a cautious approach to diagnosis. Furthermore, the relative rarity of schizophrenia in this age group has meant that most psychiatrists have relatively little experience with ‘atypical’ early presentation of the disorder.

Adult mental health disorders and their age at onset

The study of age at onset of mental health disorders is technically and conceptually difficult. It is important to consider these age distributions in order to understand causes and mechanisms of illness and to intervene at an appropriate juncture for primary and secondary prevention. This article reviews some of the approaches to studying age at onset, sets out the evidence to support the assertion that adult mental disorders begin in adolescence, and finds that perhaps half of all adult mental health disorders have begun by the teenage years. The paper then discusses whether this fits what is known about the developmental neurobiology of the brain and introduces the implications for mental health services.

Deterioration of visuospatial associative memory following a first psychotic episode: a long-term follow-up study

BACKGROUND

Cognitive deficits are a core feature of schizophrenia, and impairments in most domains are thought to be stable over the course of the illness. However, cross-sectional evidence indicates that some areas of cognition, such as visuospatial associative memory, may be preserved in the early stages of psychosis, but become impaired in later established illness stages. This longitudinal study investigated change in visuospatial and verbal associative memory following psychosis onset.

METHODS

In total 95 first-episode psychosis (FEP) patients and 63 healthy controls (HC) were assessed on neuropsychological tests at baseline, with 38 FEP and 22 HCs returning for follow-up assessment at 5-11 years. Visuospatial associative memory was assessed using the Cambridge Neuropsychological Test Automated Battery Visuospatial Paired-Associate Learning task, and verbal associative memory was assessed using Verbal Paired Associates subtest of the Wechsler Memory Scale - Revised.

RESULTS

Visuospatial and verbal associative memory at baseline did not differ significantly between FEP patients and HCs. However, over follow-up, visuospatial associative memory deteriorated significantly for the FEP group, relative to healthy individuals. Conversely, verbal associative memory improved to a similar degree observed in HCs. In the FEP cohort, visuospatial (but not verbal) associative memory ability at baseline was associated with functional outcome at follow-up.

CONCLUSIONS

Areas of cognition that develop prior to psychosis onset, such as visuospatial and verbal associative memory, may be preserved early in the illness. Later deterioration in visuospatial memory ability may relate to progressive structural and functional brain abnormalities that occurs following psychosis onset.

N-acetyl cysteine reverses bio-behavioural changes induced by prenatal inflammation, adolescent methamphetamine exposure and combined challenges

RATIONALE

Schizophrenia is associated with prenatal inflammation and/or postnatal stressors such as drug abuse, resulting in immune-redox dysfunction. Antioxidants may offer therapeutic benefits.

OBJECTIVES

The objective of this study is to investigate N-acetyl cysteine (NAC) as a therapeutic antioxidant to reverse schizophrenia-like bio-behavioural changes in rats exposed to maternal immune activation (MIA), adolescent methamphetamine (MA) or a combination thereof.

METHODS

Sprague-Dawley offspring prenatally exposed to saline/lipopolysaccharide (LPS) received saline or MA (0.2-6 mg kg^-1 twice daily × 16 days) during adolescence and divided into LPS, MA and LPS + MA groups. Vehicle/NAC (150 mg kg^-1 × 14 days) was administered following MA/saline exposure on postnatal day 51-64. Social interaction, novel object recognition and prepulse inhibition (PPI) of startle, as well as regional brain monoamines, lipid peroxidation, plasma reactive oxygen species (ROS) and pro- and anti-inflammatory cytokines (TNF-α; IL-10), were assessed.

RESULTS

NAC reversed LPS, MA and LPS + MA-induced anxiety-like social withdrawal behaviours, as well as MA and LPS + MA-induced deficits in recognition memory. PPI deficits were evident in MA, LPS and LPS + MA models, with NAC reversing that following LPS + MA. NAC reversed LPS, MA and LPS + MA-induced frontal cortical dopamine (DA) and noradrenaline (NA) elevations, LPS and LPS + MA-induced frontal cortical 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin (5-HT) and striatal NA deficits as well as LPS + MA-induced frontal cortical 5-HT turnover. Decreased IL-10 in the LPS, MA and LPS + MA animals, and increased TNF-α in the LPS and MA animals, was reversed with NAC. NAC also reversed elevated lipid peroxidation and ROS in the LPS and LPS + MA animals.

CONCLUSIONS

Prenatal LPS, LPS + postnatal MA challenge during adolescence, and to a lesser extent MA alone, promotes schizophrenia-like bio-behavioural changes later in life that are reversed by NAC, emphasizing therapeutic potential for schizophrenia and MA-associated psychosis. The nature and timing of the dual-hit are critical.

Development of a Boston Treatment Program for Youth at Clinical High Risk for Psychosis: Center for Early Detection, Assessment, and Response to Risk (CEDAR)

Over the past two decades, increasing attention has been given to the importance of early intervention for psychosis. This article describes the development of the Center for Early Detection, Assessment and Response to Risk (CEDAR), which focuses on early identification and treatment of youth at clinical high risk for psychosis. There are relatively few models in the United States for such programs, and we present our developmental story, focusing mainly on the CEDAR Clinic, as a case study of how such a program can develop. We describe the rationale, infrastructure, and services provided at the CEDAR Clinic, and present some descriptive data from the CEDAR Clinic through 2016. A case example is provided to illustrate treatment at CEDAR. We hope that the cultural history of our program's development is informative for clinicians and policy makers as one model of how to build an early intervention service. We believe that this article is timely in view of the growing momentum in the United States for developing programs for intervening as early as possible for youth at clinical high risk for psychosis.

Meta-analysis of longitudinal studies of cognition in bipolar disorder: comparison with healthy controls and schizophrenia

BACKGROUND

Bipolar disorder (BP) is associated with significant cognitive impairment. Recent evidence suggests that cognitive deficits are already evident after first-episode mania. However, it is not clear whether BP is associated with further decline in cognitive functions in individuals with established illness. Aim of this meta-analytic review was to examine longitudinal neurocognitive changes in BP and to compare trajectory of cognitive deficits in BP with schizophrenia and healthy controls.

METHODS

Electronic databases were searched for the studies published between January 1987 and November 2016. In total 22 reports were included in the current meta-analysis. The main analysis assessed the longitudinal change in cognition in 643 patients with BP. Further analyses were conducted in studies investigating cognitive changes in BP along with healthy controls (459 BP and 367 healthy controls) and schizophrenia (172 BP and 168 schizophrenia).

RESULTS

There was no cognitive decline overtime neither in short-term (mean duration = 1.5 years) nor in long-term (mean duration = 5.5 years) follow-up studies in BP. In contrast, there was evidence for modest improvements in task performance in memory and working memory at follow-up. The trajectory of cognitive functioning in BP was not significantly different from changes in schizophrenia and healthy controls.

CONCLUSIONS

Together with the findings in early BP and individuals at genetic risk for BP, current findings suggest that neurodevelopmental factors might play a significant role in cognitive deficits in BP and do not support the notion of progressive cognitive decline in most patients with BP.

Translational Genetic Modelling of 3D Craniofacial Dysmorphology: Elaborating the Facial Phenotype of Neurodevelopmental Disorders Through the "Prism" of Schizophrenia

Purpose of Review

In the context of human developmental conditions, we review the conceptualisation of schizophrenia as a neurodevelopmental disorder, the status of craniofacial dysmorphology as a clinically accessible index of brain dysmorphogenesis, the ability of genetically modified mouse models of craniofacial dysmorphology to inform on the underlying dysmorphogenic process and how geometric morphometric techniques in mutant mice can extend quantitative analysis.

Recent Findings

Mutant mice with disruption of neuregulin-1, a gene associated meta-analytically with risk for schizophrenia, constitute proof-of-concept studies of murine facial dysmorphology in a manner analogous to clinical studies in schizophrenia. Geometric morphometric techniques informed on the topography of facial dysmorphology and identified asymmetry therein.

Summary

Targeted disruption in mice of genes involved in individual components of developmental processes and analysis of resultant facial dysmorphology using geometric morphometrics can inform on mechanisms of dysmorphogenesis at levels of incisiveness not possible in human subjects.

Short-range connections in the developmental connectome during typical and atypical brain maturation

The human brain is remarkably complex with connectivity constituting its basic organizing principle. Although long-range connectivity has been focused on in most research, short-range connectivity is characterized by unique and spatiotemporally heterogeneous dynamics from infancy to adulthood. Alterations in the maturational dynamics of short-range connectivity has been associated with neuropsychiatric disorders, such as autism and schizophrenia. Recent advances in neuroimaging techniques, especially diffusion magnetic resonance imaging (dMRI), resting-state functional MRI (rs-fMRI), electroencephalography (EEG) and magnetoencephalography (MEG), have made quantification of short-range connectivity possible in pediatric populations. This review summarizes findings on the development of short-range functional and structural connections at the macroscale. These findings suggest an inverted U-shaped pattern of maturation from primary to higher-order brain regions, and possible "hyper-" and "hypo-" short-range connections in autism and schizophrenia, respectively. The precisely balanced short- and long-range connections contribute to the integration and segregation of the connectome during development. The mechanistic relationship among short-range connectivity maturation, the developmental connectome and emerging brain functions needs further investigation, including the refinement of methodological approaches.

Evolving Notions of Schizophrenia as a Developmental Neurocognitive Disorder

We review the changing conceptions of schizophrenia over the past 50 years as it became understood as a disorder of brain function and structure in which neurocognitive dysfunction was identified at different illness phases. The centrality of neurocognition has been recognized, especially because neurocognitive deficits are strongly related to social and role functioning in the illness, and as a result neurocognitive measures are used routinely in clinical assessment of individuals with schizophrenia. From the original definitions of the syndrome of schizophrenia in the early 20th century, impaired cognition, especially attention, was considered to be important. Neurocognitive impairments are found in the vast majority of individuals with schizophrenia, and they vary from mild, relatively restricted deficits, to dementia-like syndromes, as early as the first psychotic episode. Neurocognitive deficits are found in the premorbid phase in a substantial minority of pre-teenage youth who later develop schizophrenia, and they apparently worsen by the prodromal, high-risk phase in a majority of those who develop the illness. While there is limited evidence for reversibility of impairments from pharmacological interventions in schizophrenia, promising results have emerged from cognitive remediation studies. Thus, we expect cognitive interventions to play a larger role in schizophrenia in the coming years. Moreover, because youth at risk for schizophrenia can be identified by an emergent high-risk syndrome, earlier interventions might be applied in a pre-emptive way to reduce disability and improve adaptation. The notion of schizophrenia as a developmental neurocognitive disorder with stages opens up a window of possibilities for earlier interventions. (JINS, 2017, 23, 881-892).

Childhood cognitive development in 22q11.2 deletion syndrome: case-control study

Background22q11.2 deletion syndrome (22q11.2DS) is associated with a high risk of childhood as well as adult psychiatric disorders, in particular schizophrenia. Childhood cognitive deterioration in 22q11.2DS has previously been reported, but only in studies lacking a control sample.AimsTo compare cognitive trajectories in children with 22q11.2DS and unaffected control siblings.MethodA longitudinal study of neurocognitive functioning (IQ, executive function, processing speed and attention) was conducted in children with 22q11.2DS (n = 75, mean age time 1 (T₁) 9.9, time 2 (T₂) 12.5) and control siblings (n = 33, mean age T₁ 10.6, T₂ 13.4).ResultsChildren with 22q11.2DS exhibited deficits in all cognitive domains. However, mean scores did not indicate deterioration. When individual trajectories were examined, some participants showed significant decline over time, but the prevalence was similar for 22q11.2DS and control siblings. Findings are more likely to reflect normal developmental fluctuation than a 22q11.2DS-specific abnormality.ConclusionsChildhood cognitive deterioration is not associated with 22q11.2DS. Contrary to previous suggestions, we believe it is premature to recommend repeated monitoring of cognitive function for identifying individual children with 22q11.2DS at high risk of developing schizophrenia.

Clinical, Cognitive, and Neuroimaging Evidence of a Neurodevelopmental Continuum in Offspring of Probands With Schizophrenia and Bipolar Disorder

BACKGROUND

Studies in child and adolescent offspring of patients with schizophrenia or bipolar disorders may help understand the influence of neurodevelopmental factors on the premorbid phenotype of these disorders.

AIMS

To assess whether a combination of neurodevelopmental factors discriminates between young offspring of patients with schizophrenia (SzO) or bipolar disorder (BpO) and community controls (CcO). To assess the association between these factors and rates of psychiatric diagnoses in high risk (HR) youth.

METHODS

One hundred thirty-three HR offspring (47 SzO and 86 BpO) and 84 CcO, aged 6-17, underwent cross-sectional clinical, neurocognitive, and structural neuroimaging assessment. Information on perinatal events and early childhood development was also obtained. General linear mixed models were performed to assess group discrimination and association with lifetime axis I psychiatric disorders.

RESULTS

Multivariate analyses revealed that greater neurological soft signs (NSS), less total grey matter volume (GMV) and a higher frequency of obstetric complications discriminated HR offspring from CcO. When comparing each group individually, greater NSS and a higher frequency of obstetric complications discriminated SzO from CcO, and BpO from CcO, while lower intelligence also discriminated SzO from CcO and from BpO. Within HR offspring, lower intelligence and less total GMV were associated with lifetime incidence of psychiatric disorders.

CONCLUSIONS

Both SzO and BpO showed evidence of neurodevelopmental insult, although this may have a greater impact in SzO. Lower intelligence and less total GMV hold potential as biomarkers of risk for psychiatric disorders in HR youth.

Barbara Fish and a Short History of the Neurodevelopmental Hypothesis of Schizophrenia

The neurodevelopmental hypothesis of schizophrenia has become a paradigm broadly accepted in today's research in schizophrenia and its spectrum. This article traces the historical development of the neurodevelopmental hypothesis of schizophrenia up until the time of its explicit formulation in 1987, by Weinberger and by Murray and Lewis, with a main focus on the seminal contribution of Barbara Fish to its conception and elaboration.

Developmental Differences Between Schizophrenia and Bipolar Disorder

Ample evidence supports a neurodevelopmental origin in some cases of schizophrenia (SZ). More inconsistent information is available for bipolar disorder (BD). We herein review studies with a focus on premorbid (adjustment and functionality) and early developmental milestones that include both SZ and BD patients. A search was performed in the PubMed electronic database, retrieving 619 abstracts; 30 were ultimately included in this systematic review. Eight prospective cohorts, 15 retrospective studies, and 7 studies based on national registries. Psychomotor developmental deviations and general adjustment problems characterize the childhood of subjects later diagnosed with SZ or BD; they are more marked in those later diagnosed with SZ vs BD, earlier onset vs later onset, and psychotic vs nonpsychotic disorders. Cognitive impairment follows a linear risk trend for SZ and a U-shaped trend for BD. Social isolation and visuoperceptual/reading anomalies more frequently antecede SZ. Pervasive developmental disorders increase the risk for both SZ and BD, more so in cases with normal intelligence. The predictive risk of each isolated developmental marker is low, but a significant percentage of subjects with SZ and a minority of adults with BD showed signs of premorbid abnormalities in childhood. The great limitation is still the lack of studies comparing SZ and BD that include psychotic and nonpsychotic bipolar cases separately. There are many cases, even in childhood/adolescent SZ, where no premorbid anomalies are found, and immunological disorders or other etiologies should be searched for. At least in cases with clear neurodevelopmental markers, rare genetic variants should be investigated.

30 Years on: How the Neurodevelopmental Hypothesis of Schizophrenia Morphed Into the Developmental Risk Factor Model of Psychosis

At its re-birth 30 years ago, the neurodevelopment hypothesis of schizophrenia focussed on aberrant genes and early neural hazards, but then it grew to include ideas concerning aberrant synaptic pruning in adolescence. The hypothesis had its own stormy development and it endured some difficult teenage years when a resurgence of interest in neurodegeneration threatened its survival. In early adult life, it over-reached itself with some reductionists claiming that schizophrenia was simply a neurodevelopmental disease. However, by age 30, the hypothesis has matured sufficiently to incorporated childhood and adult adversity, urban living and migration, as well as heavy cannabis use, as important risk factors. Thus, it morphed into the developmental risk factor model of psychosis and integrated new evidence concerning dysregulated striatal dopamine as the final step on the pathway linking risk factors to psychotic symptoms.

Early motor developmental milestones and schizophrenia: A systematic review and meta-analysis

The neurodevelopmental hypothesis of schizophrenia proposes that impaired brain development is a cause of the illness. Early motor developmental milestones, such as learning to walk, are predictors of later schizophrenia but studies have not been systematically reviewed. The aim of the present systematic review and meta-analysis was to explore the association between early motor developmental milestones and the risk of adult schizophrenia. In addition, we updated a systematic review on motor function and risk of schizophrenia. The PubMed, PsycINFO and Scopus databases were searched for original research articles published up to July 2015. Motor milestones were measured between ages 0 and 13years. Random effect meta-analysis calculated effect estimates (Hedges' g) for the association between individual motor milestones and schizophrenia risk. An electronic database and selected articles reference list search identified 5990 articles after removing duplicates. Sixty-nine full text articles were assessed for eligibility of which six were included in the review. Five studies provided sufficient data for meta-analyses. The following motor milestones were significantly associated with adult schizophrenia risk: walking unsupported (g=0.46; 95% CI 0.27-0.64; p<0.001), standing unsupported (g=0.28; 0.16-0.40; p<0.001) and sitting unsupported (g=0.18; 0.05-0.31; p=0.007). Results for the milestones 'holding head up' and 'grabbing object' were not statistically significant. Delayed walking, sitting and standing unsupported were associated with adult onset schizophrenia. The findings emphasise the importance of timely achievement of these motor milestones in childhood and can contribute to the identification of individuals at risk of psychosis.

A prenatal interruption of DISC1 function in the brain exhibits a lasting impact on adult behaviors, brain metabolism, and interneuron development

Mental illnesses like schizophrenia (SCZ) and major depression disorder (MDD) are devastating brain disorders. The SCZ risk gene, disrupted in schizophrenia 1 (DISC1), has been associated with neuropsychiatric conditions. However, little is known regarding the long-lasting impacts on brain metabolism and behavioral outcomes from genetic insults on fetal NPCs during early life. We have established a new mouse model that specifically interrupts DISC1 functions in NPCs in vivo by a dominant-negative DISC1 (DN-DISC1) with a precise temporal and spatial regulation. Interestingly, prenatal interruption of mouse Disc1 function in NPCs leads to abnormal depression-like deficit in adult mice. Here we took a novel unbiased metabonomics approach to identify brain-specific metabolites that are significantly changed in DN-DISC1 mice. Surprisingly, the inhibitory neurotransmitter, GABA, is augmented. Consistently, parvalbumin (PV) interneurons are increased in the cingulate cortex, retrosplenial granular cortex, and motor cortex. Interestingly, somatostatin (SST) positive and neuropeptide Y (NPY) interneurons are decreased in some brain regions, suggesting that DN-DISC1 expression affects the localization of interneuron subtypes. To further explore the cellular mechanisms that cause this change, DN-DISC1 suppresses proliferation and promotes the cell cycle exit of progenitors in the medial ganglionic eminence (MGE), whereas it stimulates ectopic proliferation of neighboring cells through cell non-autonomous effect. Mechanistically, it modulates GSK3 activity and interrupts Dlx2 activity in the Wnt activation. In sum, our results provide evidence that specific genetic insults on NSCs at a short period of time could lead to prolonged changes of brain metabolism and development, eventually behavioral defects.

Predictors of change in social networks, support and satisfaction following a first episode psychosis: A cohort study

BACKGROUND

Diminished social networks are common in psychosis but few studies have measured these comprehensively and prospectively to determine how networks and support evolve during the early phase. There is little information regarding perceived support in the early phase of illness. The aim of this study was to describe social support, networks and perceived satisfaction, explore the clinical correlates of these outcomes and examine whether phases of untreated psychosis are linked with social network variables to determine potential opportunities for intervention.

METHODS

During the study period, we assessed 222 people with first-episode psychosis at entry into treatment using valid and reliable measures of diagnosis, positive and negative symptoms, periods of untreated psychosis and prodrome and premorbid adjustment. For follow-up we contacted participants to conduct a second assessment (n=158). There were 97 people who participated which represented 61% of those eligible. Social network and support information obtained at both time points included the number of friends, self-reported satisfaction with support and social network size and clinician's evaluation of the degree of support received through networks. Mixed effects modelling determined the contribution of potential explanatory variables to social support measured.

RESULTS

A number of clinical variables were linked with social networks, support and perceived support and satisfaction. The size of networks did not change over time but those with no friends and duration of untreated psychosis was significantly longer for those with no friends at entry into treatment (n=129, Median=24.5mths, IQR=7.25-69.25; Mann-Whitney U=11.78, p=0.008). Social support at baseline and at one year was predicted by homelessness (t=-2.98, p=0.001, CI -4.74 to -1.21), duration of untreated psychosis (t=-0.86, p=0.031, CI -1.65 to -0.08) and premorbid adjustment (t=-2.26, p=0.017, CI -4.11 to -0.42). Social support improved over time but the duration of untreated psychosis was not linked with the rate of improvement in this outcome.

CONCLUSIONS

Improved social support could indicate greater reliance on social support or becoming more adept at mobilising resources to meet social needs. Particularly vulnerable groups with very long duration of untreated psychosis confirm the need for earlier intervention or targeted social network interventions to preserve social connectedness.

Mapping the Consequences of Impaired Synaptic Plasticity in Schizophrenia through Development: An Integrative Model for Diverse Clinical Features

Schizophrenia is associated with alterations in sensory, motor, and cognitive functions that emerge before psychosis onset; identifying pathogenic processes that can account for this multi-faceted phenotype remains a challenge. Accumulating evidence suggests that synaptic plasticity is impaired in schizophrenia. Given the role of synaptic plasticity in learning, memory, and neural circuit maturation, impaired plasticity may underlie many features of the schizophrenia syndrome. Here, we summarize the neurobiology of synaptic plasticity, review evidence that plasticity is impaired in schizophrenia, and explore a framework in which impaired synaptic plasticity interacts with brain maturation to yield the emergence of sensory, motor, cognitive, and psychotic features at different times during development in schizophrenia. Key gaps in the literature and future directions for testing this framework are discussed.

The interplay of childhood behavior problems and IQ in the development of later schizophrenia and affective psychoses

Schizophrenia and affective psychoses are both associated with impaired social functioning, but the extent to which childhood behavioral impairments are present prior to onset of illness is less well studied. Moreover, the concurrent relationship of childhood behavior problems and premorbid IQ with subsequent psychotic disorder has not been established. We investigated whether childhood behavior problems are associated with increased risk for adult schizophrenia or affective psychosis, independently and in combination with IQ. The study included individuals with schizophrenia (N=47), affective psychoses (N=45) and non-psychotic controls (N=1496) from the New England Family Study. Behavior problems were prospectively assessed from standardized clinician observations at ages 4 and 7. IQ was assessed with the Stanford-Binet at age 4 and the Wechsler Intelligence Scale for Children at age 7. We found externalizing problems at age 4 and externalizing and internalizing problems at age 7 were associated with later schizophrenia, and both internalizing and externalizing problems at ages 4 and 7 were associated with later development of affective psychoses. Lower IQ at ages 4 and 7 was associated with schizophrenia, while lower IQ was associated with affective psychoses at age 7 only. Examined simultaneously, both lower IQ and behavior problems remained associated with risk of schizophrenia, while only behavior problems remained associated with affective psychoses. Behavior problems appear to be a general marker of risk of adult psychotic disorder, while lower childhood IQ is more specific to risk of schizophrenia. Future research should clarify the premorbid evolution of behavior and cognitive problems into adult psychosis.

Clinical correlates of hippocampus volume and shape in antipsychotic-naïve schizophrenia

While volume deficit of hippocampus is an established finding in schizophrenia, very few studies have examined large sample of patients without the confounding effect of antipsychotic treatment. Concurrent evaluation of hippocampus shape will offer additional information on the hippocampal aberrations in schizophrenia. In this study, we analyzed the volume and shape of hippocampus in antipsychotic-naïve schizophrenia patients (N=71) in comparison to healthy controls (N=82). Using 3-T MRI data, gray matter (GM) volume (anterior and posterior sub-divisions) and shape of the hippocampus were analyzed. Schizophrenia patients had significant hippocampal GM volume deficits (specifically the anterior sub-division) in comparison to healthy controls. There were significant positive correlations between anterior hippocampus volume and psychopathology scores of positive syndrome. Shape analyses revealed significant inward deformation of bilateral hippocampal surface in patients. In conclusion, our study findings add robust support for volume deficit in hippocampus in antipsychotic-naïve schizophrenia. Hippocampal shape deficits in schizophrenia observed in this study map to anterior CA1 sub-region. The differential relationship of anterior hippocampus (but not posterior hippocampus) with clinical symptoms is in tune with the findings in animal models. Further systematic studies are needed to evaluate the relationship between these hippocampal gray matter deficits with white matter and functional connectivity to facilitate understanding the hippocampal network abnormalities in schizophrenia.

Genetics implicate common mechanisms in autism and schizophrenia: synaptic activity and immunity

The diagnosis of debilitating psychiatric disorders like autism spectrum disorder (ASD) and schizophrenia (SCHZ) is on the rise. These are severe conditions that lead to social isolation and require lifelong professional care. Improved diagnosis of ASD and SCHZ provides early access to medication and therapy, but the reality is that the mechanisms and the cellular pathology underlying these conditions are mostly unknown at this time. Although both ASD and SCHZ have strong inherited components, genetic risk seems to be distributed in hundreds of variants, each conferring low risk. The poor understanding of the genetics of ASD and SCHZ is a significant hurdle to developing effective treatments for these costly conditions. The recent implementation of next-generation sequencing technologies and the creation of large consortia have started to reveal the genetic bases of ASD and SCHZ. Alterations in gene expression regulation, synaptic architecture and activity and immunity seem to be the main cellular mechanisms contributing to both ASD and SCHZ, a surprising overlap given the distinct phenotypes and onset of these conditions. These diverse pathways seem to converge in aberrant synaptic plasticity and remodelling, which leads to altered connectivity between relevant brain regions. Continuous efforts to understand the genetic basis of ASD and SCHZ will soon lead to significant progress in the mechanistic understanding of these prominent psychiatric disorders and enable the development of disease-modifying therapies for these devastating conditions.

Minor physical anomalies in bipolar I and bipolar II disorders - Results with the Méhes Scale

Minor physical anomalies (MPAs) are external markers of abnormal brain development, so the more common appearence of these signs among bipolar I and bipolar II patients can confirm the possibility of a neurodevelopmental deficit in these illnesses. The aim of the present study was to investigate the rate and topological profile of minor physical anomalies in patients with bipolar I and - first in literature - with bipolar II disorders compared to matched healthy control subjects. Using a list of 57 minor physical anomalies (the Méhes Scale), 30 bipolar I and 30 bipolar II patients, while as a comparison 30 matched healthy control subjects were examined. Significant differences were detected between the three groups comparing the total number of minor physical anomalies, minor malformations and phenogenetic variants and in the cases of the ear and the mouth regions. The individual analyses of the 57 minor physical anomalies by simultaneous comparison of the three groups showed, that in the cases of furrowed tongue and high arched palate were significant differences between the three groups. The results can promote the concept, that a neurodevelopmental deficit may play a role in the etiology of both bipolar I and bipolar II disorders.

Rare damaging variants in DNA repair and cell cycle pathways are associated with hippocampal and cognitive dysfunction: a combined genetic imaging study in first-episode treatment-naive patients with schizophrenia

Schizophrenia is a complex neurodevelopmental disorder where changes in both hippocampus and memory-related cognitive functions are central. However, the exact relationship between neurodevelopmental-genetic factors and hippocampal-cognitive dysfunction remains unclear. The general aim of our study is to link the occurrence of rare damaging mutations involved in susceptibility gene pathways to the structure and function of hippocampus in order to define genetically and phenotypically based subgroups in schizophrenia. In the present study, by analyzing the exome sequencing and magnetic resonance imaging data in 94 first-episode treatment-naive schizophrenia patients and 134 normal controls, we identified that a cluster of rare damaging variants (RDVs) enriched in DNA repair and cell cycle pathways was present only in a subgroup including 39 schizophrenic patients. Furthermore, we found that schizophrenic patients with this RDVs show increased resting-state functional connectivity (rsFC) between left hippocampus (especially for left dentate gyrus) and left inferior parietal cortex, as well as decreased rsFC between left hippocampus and cerebellum. Moreover, abnormal rsFC was related to the deficits of spatial working memory (SWM; that is known to recruit the hippocampus) in patients with the RDVs. Taken together, our data demonstrate for the first time, to our knowledge, that damaging rare variants of genes in DNA repair and cell cycle pathways are associated with aberrant hippocampal rsFC, which was further relative to cognitive deficits in first-episode treatment-naive schizophrenia. Therefore, our data provide some evidence for the occurrence of phenotypic alterations in hippocampal and SWM function in a genetically defined subgroup of schizophrenia.

Diminished Infant P50 Sensory Gating Predicts Increased 40-Month-Old Attention, Anxiety/Depression, and Externalizing Symptoms

OBJECTIVE

When behavioral problems resulting from attentional difficulties present, often in preschool, it is unknown whether these problems represent preexisting altered brain development or new brain changes. This study examines whether infant sensory gating of auditory evoked potentials predicts parent-reported behavior at 40 months.

METHOD

P50 sensory gating, an auditory evoked potential measure reflective of inhibitory processes in the brain, was measured in 50 infants around 70 days old. Parents, using the Child Behavior Checklist, reported on the child's behavior at 40 months.

RESULTS

Controlling for gender, infants with diminished sensory gating had more problems later with externalizing behavior ( F = 4.17, ndf = 1, ddf = 46, p = .047), attentional problems ( F = 5.23, ndf = 1, ddf = 46, p = .027), and anxious/depressed symptoms ( F = 5.36, ndf = 1, ddf = 46, p = .025).

CONCLUSION

Diminished infant P50 sensory gating predicts attention symptoms 3 years later. These results support the hypothesis that preschool attentional dysfunction may relate to altered brain development that is detectable years prior to symptom onset.

The longitudinal association between external locus of control, social cognition and adolescent psychopathology

PURPOSE

To investigate the longitudinal associations between social cognitive ability an external locus of control (externality) and adolescent psychopathology.

METHODS

7058 participants from a prospective population-based cohort provided data on externality, social communication, and emotion perception between 7 and 16 years and psychotic experiences and depressive symptoms at 12 and 18 years. Bivariate probit modelling was used to investigate associations between these risk factors and psychopathological outcomes.

RESULTS

Externality was associated with psychopathology at 12 (psychotic experiences OR 1.23 95% CI 1.14, 1.33; depression OR 1.12 95% CI 1.02, 1.22) and 18 years (psychotic experiences OR 1.38 95% CI 1.23, 1.55; depression OR 1.40 95% CI 1.28, 1.52). Poor social communication was associated with depression at both ages (12 years OR 1.22 95% CI 1.11, 1.34; 18 years OR 1.21 95% CI 1.10, 1.33) and marginally associated with psychotic experiences. There was marginal evidence of a larger association between externality and psychotic experiences at 12 years (p = 0.06) and between social communication and depression at 12 years (p = 0.03).

CONCLUSIONS

Externality was more strongly associated with psychotic experiences. At 18 years change in externality, between 8 and 16 years were associated with a larger increase in the risk of depression. Poor social communication was more strongly associated with depression.

Academic Performance in Children of Mothers With Schizophrenia and Other Severe Mental Illness, and Risk for Subsequent Development of Psychosis: A Population-Based Study

OBJECTIVE

We examined the academic performance at age 12 years of children of mothers diagnosed with schizophrenia or other severe mental illness using a large whole-population birth cohort born in Western Australia. We investigated the association between academic performance and the subsequent development of psychotic illness.

METHOD

The sample comprised 3169 children of mothers with severe mental illness (schizophrenia, bipolar disorder, unipolar major depression, delusional disorder or other psychoses; ICD-9 codes 295-298), and 88 353 children of comparison mothers without known psychiatric morbidity. Academic performance of children was indexed on a mandatory state-wide test of reading, spelling, writing and numeracy.

RESULTS

A larger proportion of children (43.1%) of mothers with severe mental illness performed below the acceptable standard than the reference group (30.3%; children of mothers with no known severe mental illness). After adjusting for covariates, children of mothers with any severe mental illness were more likely than the reference group to perform below-benchmark on all domains except reading. For all children, poor spelling was associated with the later development of psychosis, but particularly for those at familial risk for severe mental illness (hazard ratio [HR] = 1.81; 95% CI for HR = 1.21, 2.72).

CONCLUSIONS

Children of mothers with a severe mental illness are at increased risk for sub-standard academic achievement at age 12 years, placing these children at disadvantage for the transition to secondary school. For children with familial risk for severe mental illness, very poor spelling skills at age 12 years may be an indicator of risk for later psychotic disorder.

Visual Population Receptive Fields in People with Schizophrenia Have Reduced Inhibitory Surrounds

People with schizophrenia (SZ) experience abnormal visual perception on a range of visual tasks, which have been linked to abnormal synaptic transmission and an imbalance between cortical excitation and inhibition. However, differences in the underlying architecture of visual cortex neurons, which might explain these visual anomalies, have yet to be reported in vivo Here, we probed the neural basis of these deficits using fMRI and population receptive field (pRF) mapping to infer properties of visually responsive neurons in people with SZ. We employed a difference-of-Gaussian model to capture the center-surround configuration of the pRF, providing critical information about the spatial scale of the pRFs inhibitory surround. Our analysis reveals that SZ is associated with reduced pRF size in early retinotopic visual cortex, as well as a reduction in size and depth of the inhibitory surround in V1, V2, and V4. We consider how reduced inhibition might explain the diverse range of visual deficits reported in SZ.SIGNIFICANCE STATEMENT People with schizophrenia (SZ) experience abnormal perception on a range of visual tasks, which has been linked to abnormal synaptic transmission and an imbalance between cortical excitation/inhibition. However, associated differences in the functional architecture of visual cortex neurons have yet to be reported in vivo We used fMRI and population receptive field (pRF) mapping to demonstrate that the fine-grained functional architecture of visual cortex in people with SZ differs from unaffected controls. SZ is associated with reduced pRF size in early retinotopic visual cortex largely due to reduced inhibitory surrounds. An imbalance between cortical excitation and inhibition could drive such a change in the center-surround pRF configuration and ultimately explain the range of visual deficits experienced in SZ.

Should psychiatrists be more cautious about the long-term prophylactic use of antipsychotics?

Patients who recover from an acute episode of psychosis are frequently prescribed prophylactic antipsychotics for many years, especially if they are diagnosed as having schizophrenia. However, there is a dearth of evidence concerning the long-term effectiveness of this practice, and growing concern over the cumulative effects of antipsychotics on physical health and brain structure. Although controversy remains concerning some of the data, the wise psychiatrist should regularly review the benefit to each patient of continuing prophylactic antipsychotics against the risk of side-effects and loss of effectiveness through the development of supersensitivity of the dopamine D₂ receptor. Psychiatrists should work with their patients to slowly reduce the antipsychotic to the lowest dose that prevents the return of distressing symptoms. Up to 40% of those whose psychosis remits after a first episode should be able to achieve a good outcome in the long term either with no antipsychotic medication or with a very low dose.

The communicative impairment as a core feature of schizophrenia: Frequency of pragmatic deficit, cognitive substrates, and relation with quality of life

BACKGROUND

Impairments in specific aspects of pragmatic competence, supporting the use of language in context, are largely documented in schizophrenia and might represent an indicator of poor outcome. Yet pragmatics is rarely included in clinical settings. This paper aims to promote a clinical consideration of pragmatics as a target of assessment and intervention. We investigated the frequency of the pragmatic deficit, its cognitive substrates, and the relation with quality of life.

METHODS

Pragmatic abilities were compared in a sample of patients with schizophrenia and healthy controls based on a comprehensive pragmatic test (APACS). We assessed also for psychopathology, cognition, social cognition, and quality of life. We explored the co-occurrence of deficits in different domains, and we used multiple regressions to investigate the effect of cognition and social cognition on pragmatics, and of pragmatics on quality of life.

RESULTS

Pragmatic abilities, especially comprehending discourse and non-literal meanings, were compromised in schizophrenia, with 77% of patients falling below cutoff. Pragmatic deficit co-occurred with cognitive or socio-cognitive deficits in approximately 30% of cases. Multiple regression analysis confirmed the interplay of cognition and social cognition in pragmatic behavior. Quality of life was predicted by symptoms and by pragmatic abilities.

CONCLUSIONS

The high frequency of impairment suggests that the pragmatic deficit is a core feature of schizophrenia, associated with quality of life. Cognitive and socio-cognitive abilities might represent necessary though not sufficient building blocks for the acquisition of pragmatic abilities throughout development. Therefore, a more precise incorporation of pragmatics in the description of the pathology is of high clinical and translational relevance.

Weaving a Net of Neurobiological Mechanisms in Schizophrenia and Unraveling the Underlying Pathophysiology

Perineuronal nets (PNNs) are enigmatic structures composed of extracellular matrix molecules that encapsulate the soma, dendrites, and axon segments of neurons in a lattice-like fashion. Although most PNNs condense around parvalbumin-expressing gamma-aminobutyric acidergic interneurons, some glutamatergic pyramidal cells in the brain are also surrounded by PNNs. Experimental findings suggest pivotal roles of PNNs in the regulation of synaptic formation and function. Also, an increasing body of evidence links PNN abnormalities to schizophrenia. The number of PNNs progressively increases during postnatal development until plateauing around the period of late adolescence and early adulthood, which temporally coincides with the age of onset of schizophrenia. Given the established role of PNNs in modulating developmental plasticity, the PNN represents a possible candidate for altering the onset and progression of schizophrenia. Similarly, the reported function of PNNs in regulating the trafficking of glutamate receptors places them in a critical position to modulate synaptic pathology, considered a cardinal feature of schizophrenia. We discuss the physiologic role of PNNs in neural function, synaptic assembly, and plasticity as well as how they interface with circuit/system mechanisms of cognition. An integrated understanding of these neurobiological processes should provide a better basis to elucidate how PNN abnormalities influence brain function and contribute to the pathogenesis of neurodevelopmental disorders such as schizophrenia.

Genome-wide significant schizophrenia risk variation on chromosome 10q24 is associated with altered cis-regulation of BORCS7, AS3MT, and NT5C2 in the human brain

Chromosome 10q24.32-q24.33 is one of the most robustly supported risk loci to emerge from genome-wide association studies (GWAS) of schizophrenia. However, extensive linkage disequilibrium makes it difficult to distinguish the actual susceptibility gene(s) at the locus, limiting its value for improving biological understanding of the condition. In the absence of coding changes that can account for the association, risk is likely conferred by altered regulation of one or more genes in the region. We, therefore, used highly sensitive measures of allele-specific expression to assess cis-regulatory effects associated with the two best-supported schizophrenia risk variants (SNP rs11191419 and indel ch10_104957618_I/rs202213518) on the primary positional candidates BORCS7, AS3MT, CNNM2, and NT5C2 in the human brain. Heterozygosity at rs11191419 was associated with increased allelic expression of BORCS7 and AS3MT in the fetal and adult brain, and with reduced allelic expression of NT5C2 in the adult brain. Heterozygosity at ch10_104957618_I was associated with reduced allelic expression of NT5C2 in both the fetal and adult brain. Comparisons between cDNA ratios in heterozygotes and homozygotes for the risk alleles indicated that cis-effects on NT5C2 expression in the adult dorsolateral prefrontal cortex could be largely accounted for by genotype at these two risk variants. While not excluding effects on other genes in the region, this study implicates altered neural expression of BORCS7, AS3MT, and NT5C2 in susceptibility to schizophrenia arising from genetic variation at the chromosome 10q24 locus. © 2016 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc.

Association between childhood psychiatric disorders and psychotic experiences in adolescence: A population-based longitudinal study

BACKGROUND

Adolescent psychotic experiences (PEs) are common, and are associated with both psychotic and non-psychotic illnesses. In order to examine psychopathological and cognitive antecedents of adolescent PEs, we have conducted a longitudinal study of common childhood psychiatric disorders and subsequent adolescent PEs in the population-based prospective ALSPAC birth cohort.

METHOD

Depression, anxiety, attention deficit hyperactivity disorder, oppositional defiant or conduct disorder, and pervasive developmental disorder were diagnosed according to DSM-IV criteria in 8253 participants at age 8years. IQ was assessed by WISC-III also at 8years. PEs, depressive and anxiety symptoms were assessed at 13years. Logistic regression calculated odds ratio (OR) for PEs at 13years associated with psychiatric disorders at 8years. Linear regression calculated mean difference in IQ between groups with and without psychiatric disorder. Mediating effects of IQ, mood and anxiety symptoms on the psychiatric disorder-PEs relationship were examined.

RESULTS

In total, 599 children were assessed to have a DSM-IV psychiatric disorder at 8years (7.2%). These children compared with those without any psychiatric disorder performed worse on all measures of IQ; adjusted mean difference in total IQ -6.17 (95% CI, -7.86, -4.48). Childhood psychiatric disorders were associated with PEs subsequently in adolescence; adjusted OR 1.96 (95% CI, 1.47-2.68). The association between psychiatric disorder and subsequent PEs was partly mediated by, independently, IQ deficit at 8years and depressive and anxiety symptoms at 13years.

CONCLUSIONS

The findings indicate that adolescent PEs are associated with general cognitive ability and past and present psychopathological factors.

Longitudinal change in neurocognition and its relation to symptomatic and functional changes over 2years in individuals at clinical high-risk for psychosis

BACKGROUND

Negative symptoms and functional disability represent the core of schizophrenia and both are associated with cognitive impairments. We explored the course of cognitive change and its relation to symptomatic and functional changes in individuals at clinical high-risk (CHR) for psychosis to identify cognitive indicators of long-term course. Such attempts may offer insight into the pathological changes associated with the development of illness in the prodromal state.

METHODS

Forty-seven CHR individuals completed neurocognitive, clinical, and functional assessments at baseline and 2-year follow-up; twenty-eight healthy controls were assessed for neurocognitive and functional measures at baseline and 2-year follow-up. The delta values of CHR individuals in neurocognitive, clinical, and functional domains were determined from differences between baseline and follow-up scores to estimate the degree of change.

RESULTS

Although overall longitudinal cognitive performance of CHR individuals improved, the magnitude of improvement was not statistically different from that of normal controls at the group level. However, the individual data yielded two groups of CHR subjects showing opposite trajectories of cognitive change in semantic fluency (i.e., improvement or decline), which was significantly associated with changes in negative symptoms and functioning. Moreover, the relationships between negative symptoms and functioning were more strengthened over time than baseline.

CONCLUSIONS

Our findings show that semantic fluency seems to be a neurocognitive indicator reflecting clinical courses in CHR individuals. The longitudinal relationship of negative symptoms and functioning with semantic fluency may represent ongoing pathological processes in neural systems involving aberrant fronto-temporal interaction in the early phase of schizophrenia.

Cognitive functioning in individuals at ultra-high risk for psychosis, first-degree relatives of patients with psychosis and patients with first-episode schizophrenia

OBJECTIVE

The aim of the present study was to investigate and compare cognitive functioning of first-degree relatives of people with schizophrenia who were also at ultra-high risk (UHR) for psychosis with patients with first-episode (FE) schizophrenia, first degree relatives of patients not fulfilling UHR criteria (FDR), and healthy control (HC) subjects.

METHOD

Forty subjects in each group were included, underwent a face-to-face interview and completed a neurocognitive test battery, including the Trail Making Test-A (TMT-A, psychomotor functions), Stroop Color Word Test (attention), Digit Symbol Coding Test (DST, processing speed and working memory) and Hopkins Verbal Leaning Test-Revised (HVLT-R, verbal memory).

RESULTS

Functioning in all the cognitive test domains displayed a gradual decrease from the HC, FDR, UHR to FE groups. After controlling for covariates, there were still significant differences in TMT-A (F(7160)=35.4, P<0.001), DST (F(7160)=38.9, P<0.001), Stroop Color Word Test (F(7160)=35.0, P<0.001), Stroop Word Test (F(7160)=36.2, P<0.001), Stroop Color Test (F(7160)=40.9, P<0.001) and HVLT-R (F(7160)=62.5, P<0.001) between the four groups, indicating that the cognitive functioning in the UHR group was intermediate between the FE and FDR groups, while the FDR group had poorer performance than the HC group, and the FE group had the poorest cognitive functioning across all four examined domains.

CONCLUSION

The results indicate that impairments in processing speed, attention, working memory and verbal memory exist in both UHR and FDR subjects. In order to clarify the associations between cognitive functioning and UHR and schizophrenia, longitudinal studies are warranted.

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

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

Nicotine ameliorates schizophrenia-like cognitive deficits induced by maternal LPS exposure: a study in rats

Maternal exposure to infectious agents is a predisposing factor for schizophrenia with associated cognitive deficits in offspring. A high incidence of smoking in these individuals in adulthood might be, at least in part, due to the cognitive-enhancing effects of nicotine. Here, we have used prenatal exposure to maternal lipopolysaccharide (LPS, bacterial endotoxin) at different time points as a model for cognitive deficits in schizophrenia to determine whether nicotine reverses any associated impairments. Pregnant rats were treated subcutaneously with LPS (0.5 mg/kg) at one of three neurodevelopmental time periods [gestation days (GD) 10-11, 15-16, 18-19]. Cognitive assessment in male offspring commenced in early adulthood [postnatal day (PND) 60] and included: prepulse inhibition (PPI), latent inhibition (LI) and delayed non-matching to sample (DNMTS). Following PND 100, daily nicotine injections (0.6 mg/kg, subcutaneously) were administered, and animals were re-tested in the same tasks (PND 110). Only maternal LPS exposure early during fetal neurodevelopment (GD 10-11) resulted in deficits in all tests compared to animals that had been prenatally exposed to saline at the same gestational time point. Repeated nicotine treatment led to global (PPI) and selective (LI) improvements in performance. Early but not later prenatal LPS exposure induced consistent deficits in cognitive tests with relevance for schizophrenia. Nicotine reversed the LPS-induced deficits in selective attention (LI) and induced a global enhancement of sensorimotor gating (PPI).

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.

Cognitive bias salience in patients with schizophrenia in relation to social functioning: A four-case observation study

Neurocognition and social cognition are the core deficits influencing social outcomes in patients with schizophrenia. These deficits are present in the prodromal phase, throughout the illness and in first-degree relatives. They are considered in the framework of neurodevelopmental or neurodegenerative models as well as candidates for endophenotypes of schizophrenia. Four clinical cases with patients reflecting different cognitive profiles were chosen to demonstrate heterogeneity of cognitive biases and their influence on social function in vivo. The patients had undergone a number of neurocognitive and social cognitive measures. Better functioning was observed in patients with less affected domains of emotional processing and theory of mind, while neurocognitive statuses were incongruent to levels of social functioning. Further investigation on large samples concerning capacity for empathy and its role in social functioning is needed.

Genome-wide investigation of schizophrenia associated plasma Ndel1 enzyme activity

Ndel1 is a DISC1-interacting oligopeptidase that cleaves in vitro neuropeptides as neurotensin and bradykinin, and which has been associated with both neuronal migration and neurite outgrowth. We previously reported that plasma Ndel1 enzyme activity is lower in patients with schizophrenia (SCZ) compared to healthy controls (HCs). To our knowledge, no previous study has investigated the genetic factors associated with the plasma Ndel1 enzyme activity. In the current analyses, samples from 83 SCZ patients and 92 control subjects that were assayed for plasma Ndel1 enzyme activity were genotyped on Illumina Omni Express arrays. A genetic relationship matrix using genome-wide information was then used for ancestry correction, and association statistics were calculated genome-wide. Ndel1 enzyme activity was significantly lower in patients with SCZ (t=4.9; p<0.001) and was found to be associated with CAMK1D, MAGI2, CCDC25, and GABGR3, at a level of suggestive significance (p<10(-6)), independent of the clinical status. Then, we performed a model to investigate the observed differences for case/control measures. 2 SNPs at region 1p22.2 reached the p<10(-7) level. ZFPM2 and MAD1L1 were the only two genes with more than one hit at 10(-6) order of p value. Therefore, Ndel1 enzyme activity is a complex trait influenced by many different genetic variants that may contribute to SCZ physiopathology.

Research Review: Do motor deficits during development represent an endophenotype for schizophrenia? A meta-analysis

BACKGROUND

Early detection of schizophrenia risk is a critical goal in the field. Endophenotypes in children to relatives of affected individuals may contribute to this early detection. One of the lowest cost and longest theorized domains is motor development in children.

METHODS

A meta-analysis was conducted comparing individuals ≤21 years old with affected first-degree relatives (FDR) with (1) individuals from unaffected families (controls), or (2) individuals with FDR having other psychiatric disorders. Studies were classified by motor outcome and separate meta-analyses were performed across six correlated domains, with available N varying by domain.

RESULTS

Inclusion criteria were met by k = 23 independent studies with a total N = 18,582, and N across domains varying from 167 to 8619. The youth from affected families had delays in gross and fine motor development in infancy (k = 3, n = 167, Hedges'g = 0.644, confidence intervals (CI) = [0.328, 0.960], p < .001), walking milestones (k = 3, n = 608, g = 0.444, CI = [0.108, 0.780], p = .01), coordination (k = 8, n = 8619, g = 0.625, CI = [0.453, 0.797], p < .0001), and had more abnormal movements such as involuntary movements (k = 6, n = 8365, g = 0.291, CI = [0.041, 0.542], p = .02) compared with controls. However, not all effects survived correction for publication bias. Effects for neurological soft signs were small and not reliably different from zero (k = 4, n = 548, g = 0.238, CI = [-0.106, 0.583], p = .18). When comparing the FDR group to youth from families with other psychiatric disorders, the FDR group was distinguished by poorer gross and fine motor skills (k = 2, n = 275, g = 0.847, CI = [0.393, 1.300], p < .001).

CONCLUSIONS

Motor deficits during development likely represent an endophenotype for schizophrenia, although its specificity is limited in relation to other serious mental disorders. It holds promise as a low cost domain for early risk detection, although it will have to be combined with other indicators to achieve clinically usable prediction accuracy. Impaired coordination was the most robust result with a moderate effect size and lack of heterogeneity and publication bias.

Exposure to genocide and the risk of schizophrenia: a population-based study

BACKGROUND

No evidence exists on the association between genocide and the incidence of schizophrenia. This study aims to identify critical periods of exposure to genocide on the risk of schizophrenia.

METHOD

This population-based study comprised of all subjects born in European nations where the Holocaust occurred from 1928 to 1945, who immigrated to Israel by 1965 and were indexed in the Population Register (N = 113 932). Subjects were followed for schizophrenia disorder in the National Psychiatric Case Registry from 1950 to 2014. The population was disaggregated to compare groups that immigrated before (indirect exposure: n = 8886, 7.8%) or after (direct exposure: n = 105 046, 92.2%) the Nazi or fascist era of persecutions began. The latter group was further disaggregated to examine likely initial prenatal or postnatal genocide exposures. Cox regression modelling was computed to compare the risk of schizophrenia between the groups, adjusting for confounders.

RESULTS

The likely direct group was at a statistically (p < 0.05) greater risk of schizophrenia (hazard ratio = 1.27, 95% confidence interval 1.06-1.51) than the indirect group. Also, the likely combined in utero and postnatal, and late postnatal (over age 2 years) exposure subgroups were statistically at greater risk of schizophrenia than the indirect group (p < 0.05). The likely in utero only and early postnatal (up to age 2 years) exposure subgroups compared with the indirect exposure group did not significantly differ. These results were replicated across three sensitivity analyses.

CONCLUSIONS

This study showed that genocide exposure elevated the risk of schizophrenia, and identified in utero and postnatal (combined) and late postnatal (age over 2 years) exposures as critical periods of risk.

The association between childhood autistic traits and adolescent psychotic experiences is explained by general neuropsychiatric problems

Studies suggest associations between childhood autistic traits and adolescent psychotic experiences. However, recent research suggests that a general neuropsychiatric problems factor predicts adverse outcomes better than specific diagnostic entities. To examine if the alleged association between autistic traits and psychotic experiences could rather be explained by a general neuropsychiatric problems factor comprising symptoms of ADHD, tic disorder, developmental coordination disorder, and learning disorder, we conducted a prospective cohort study based on the Child and Adolescent Twin Study in Sweden. In addition, we examined the genetic and environmental influences on the associations. A total of 9,282 twins with data on childhood autistic traits and other neuropsychiatric problems, and follow-up data on psychotic experiences at ages 15 and/or 18 years were included. First, psychotic experiences were regressed on autistic traits and second, the general neuropsychiatric problems factor was added to the model. Auditory hallucinations were analyzed separately from the other psychotic experiences. Finally, twin analyses were employed to disentangle genetic from environmental influences in the observed associations. Replicating prior research, significant associations were found between autistic traits in childhood and auditory hallucinations at ages 15 and 18. However, after controlling for the general neuropsychiatric problems factor, the associations between autistic traits and auditory hallucinations disappeared, whereas the association between the general neuropsychiatric problems factor and auditory hallucinations persisted after controlling for autistic traits. Twin analyses revealed that the association between the general neuropsychiatric problems factor and auditory hallucinations was driven by shared genetic influences. © 2015 Wiley Periodicals, Inc.