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Objective: Schizophrenia, a complex psychiatric disorder, is often associated with cognitive, neurological and neuroimaging abnormalities. The processes underlying these abnormalities, and whether a subset of people with schizophrenia have a neuroprogressive or neurodegenerative component to schizophrenia, remain largely unknown. Examining fluid biomarkers of diverse types of neuronal damage could increase our understanding of these processes, as well as potentially provide clinically useful biomarkers, for example with assisting with differentiation from progressive neurodegenerative disorders such as Alzheimer and frontotemporal dementias., Methods: This study measured plasma neurofilament light chain protein (NfL) using ultrasensitive Simoa technology, to investigate the degree of neuronal injury in a well-characterised cohort of people with treatment-resistant schizophrenia on clozapine ( n  = 82), compared to first-degree relatives (an at-risk group, n  = 37), people with schizophrenia not treated with clozapine ( n  = 13), and age- and sex-matched controls ( n  = 59)., Results: We found no differences in NfL levels between treatment-resistant schizophrenia (mean NfL, M = 6.3 pg/mL, 95% confidence interval: [5.5, 7.2]), first-degree relatives (siblings, M = 6.7 pg/mL, 95% confidence interval: [5.2, 8.2]; parents, M after adjusting for age = 6.7 pg/mL, 95% confidence interval: [4.7, 8.8]), controls (M = 5.8 pg/mL, 95% confidence interval: [5.3, 6.3]) and not treated with clozapine (M = 4.9 pg/mL, 95% confidence interval: [4.0, 5.8]). Exploratory, hypothesis-generating analyses found weak correlations in treatment-resistant schizophrenia, between NfL and clozapine levels (Spearman's r  = 0.258, 95% confidence interval: [0.034, 0.457]), dyslipidaemia ( r  = 0.280, 95% confidence interval: [0.064, 0.470]) and a negative correlation with weight ( r  = -0.305, 95% confidence interval: [-0.504, -0.076])., Conclusion: Treatment-resistant schizophrenia does not appear to be associated with neuronal, particularly axonal degeneration. Further studies are warranted to investigate the utility of NfL to differentiate treatment-resistant schizophrenia from neurodegenerative disorders such as behavioural variant frontotemporal dementia, and to explore NfL in other stages of schizophrenia such as the prodome and first episode.

Aim: The aim of this study was to develop a suspicion index that aids diagnosis of secondary schizophrenia spectrum disorders in regular clinical practice., Method: We used the Delphi method to rate and refine questionnaire items in consecutive rounds. Differences in mean expert responses for schizophrenia spectrum disorders and secondary schizophrenia spectrum disorders populations allowed to define low/middle/high predictive items, which received different weights. Algorithm performance was tested in 198 disease profiles by means of sensitivity and specificity., Results: Twelve experts completed the Delphi process, and consensus was reached in 19/24 (79.2%) items for schizophrenia spectrum disorders and 17/24 (70.8%) for secondary schizophrenia spectrum disorders. We assigned rounded values to each item category according to their predictive potential. A differential distribution of scores was observed between schizophrenia spectrum disorders and secondary schizophrenia spectrum disorders when applying the suspicion index for validation to 198 disease profiles. Sensitivity and specificity analyses allowed to set a >8/10/16 risk prediction score as a threshold to consider medium/high/very high suspicion of secondary schizophrenia spectrum disorders., Conclusion: Our final outcome was the Secondary Schizophrenia Suspicion Index, the first paper-based and reliable algorithm to discriminate secondary schizophrenia spectrum disorders from schizophrenia spectrum disorders with the potential to help improve the detection of secondary schizophrenia spectrum disorder cases in clinical practice.

A literature review was conducted, using the computerized "Online Mendelian Inheritance in Man" (OMIM) and PubMed, to identify inborn errors of metabolism (IEM) in which psychosis may be a predominant feature or the initial presenting symptom. Different combinations of the following keywords were searched using OMIM: "psychosis", "schizophrenia", or "hallucinations" and "metabolic", "inborn error of metabolism", "inborn errors of metabolism", "biochemical genetics", or "metabolic genetics". The OMIM search generated 126 OMIM entries, 40 of which were well known IEM. After removing IEM lacking evidence in PubMed for an association with psychosis, 29 OMIM entries were identified. Several of these IEM are treatable. They involve different small organelles (lysosomes, peroxisomes, mitochondria), iron or copper accumulation, as well as defects in other met-abolic pathways (e.g., defects leading to hyperammonemia or homocystinemia). A clinical checklist summarizing the key features of these conditions and a guide to clinical approach are provided. The genes corresponding to each of these con-ditions were identified. Whole exome data from 2545 adult cases with schizophrenia and 2545 unrelated controls, accessed via the Database of Genotypes and Phenotypes (dbGaP), were analyzed for rare functional variants in these genes. The odds ratio of having a rare functional variant in cases versus controls was calculated for each gene. Eight genes are significantly associated with schizophrenia (p < 0.05, OR >1) using an unselected group of adult patients with schizophrenia. Increased awareness of clinical clues for these IEM will optimize referrals and timely metabolic interventions.

This study focuses on a group of patients with chronic schizophrenia who have a more severe form of the disorder, as indicated by socio-functional decline, treatment resistance, and recurrent hospitalisation. Previous research has suggested that the pattern and severity of cognitive deficits in people with severe chronic schizophrenia is similar to that observed in behavioural variant frontotemporal dementia (bvFTD). In the current study, we compared neurocognitive performance in 16 cognitive domains in 7 inpatients with severe chronic schizophrenia, 13 community-dwelling outpatients with chronic schizophrenia, 12 patients with bvFTD, and 18 healthy controls. Our findings revealed more similar cognitive profiles between the schizophrenia inpatient and bvFTD groups compared to the schizophrenia outpatient group, who outperformed the former groups. The current results provide preliminary evidence for a distinct schizophrenia subgroup, distinguishable from other chronic schizophrenia patients by poorer clinical and functional status, who have levels of cognitive impairment comparable to those seen in bvFTD patients., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Abnormalities in hippocampal morphology are characteristic of schizophrenia and have also been reported in chronic cannabis users. There is a paucity of research investigating potential additive effects of cannabis use on brain pathology associated with schizophrenia. In this study, we performed hippocampal shape analysis in cannabis-using and non-using patients with schizophrenia, healthy cannabis users and healthy non-using controls. Hippocampal shape changes were observed in each group relative to controls, with the greatest degree of alterations (i.e., deflations across the hippocampus, and with an anterior predisposition), in cannabis-using schizophrenia patients. These alterations were associated with cannabis use patterns and psychotic symptoms., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Although historically gray matter changes have been the focus of neuropathological and neuroradiological studies in schizophrenia, in recent years an increasing body of research has implicated white matter structures and its constituent components (axons, their myelin sheaths and supporting oligodendrocytes). This article summarizes this body of literature, examining neuropathological, neurogenetic and neuroradiological evidence for white matter pathology in schizophrenia. We then look at the possible role that antipsychotic medication may play in these studies, examining both its role as a potential confounder in studies examining neuronal density and brain volume, but also the possible role that these medications may play in promoting myelination through their effects on oligodendrocytes. Finally, the role of potential novel therapies is discussed.

Despite an increasing number of published voxel based morphometry studies of schizophrenia, there has been no adequate attempt to examine gray (GM) and white matter (WM) abnormalities and the heterogeneity of published findings. In the current article, we used a coordinate based meta-analysis technique to simultaneously examine GM and WM abnormalities in schizophrenia and to assess the effects of gender, chronicity, negative symptoms and other clinical variables. 79 studies meeting our inclusion criteria were included in the meta-analysis. Schizophrenia was associated with GM reductions in the bilateral insula/inferior frontal cortex, superior temporal gyrus, anterior cingulate gyrus/medial frontal cortex, thalamus and left amygdala. In WM analyses of volumetric and diffusion-weighted images, schizophrenia was associated with decreased FA and/or WM in interhemispheric fibers, anterior thalamic radiation, inferior longitudinal fasciculi, inferior frontal occipital fasciculi, cingulum and fornix. Male gender, chronic illness and negative symptoms were associated with more severe GM abnormalities and illness chronicity was associated with more severe WM deficits. The meta-analyses revealed overlapping GM and WM structural findings in schizophrenia, characterized by bilateral anterior cortical, limbic and subcortical GM abnormalities, and WM changes in regions including tracts that connect these structures within and between hemispheres. However, the available findings are biased towards characteristics of schizophrenia samples with poor prognosis., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Background: Morphological abnormalities of the superior temporal gyrus have been consistently reported in schizophrenia, but the timing of their occurrence remains unclear., Aims: To determine whether individuals exhibit superior temporal gyral changes before the onset of psychosis., Method: We used magnetic resonance imaging to examine grey matter volumes of the superior temporal gyrus and its subregions (planum polare, Heschl's gyrus, planum temporale, and rostral and caudal regions) in 97 antipsychotic-naive individuals at ultra-high risk of psychosis, of whom 31 subsequently developed psychosis and 66 did not, and 42 controls., Results: Those at risk of psychosis had significantly smaller superior temporal gyri at baseline compared with controls bilaterally, without any prominent subregional effect; however, there was no difference between those who did and did not subsequently develop psychosis., Conclusions: Our findings indicate that grey matter reductions of the superior temporal gyrus are present before psychosis onset, and are not due to medication, but these baseline changes are not predictive of transition to psychosis.

We describe the differential presentation of schizophrenia-like psychosis in two siblings with the 'variant' biochemical presentation of adult Niemann-Pick disease type C. The male sibling presented with psychosis at age 16 years and cognitive and motor disturbance at age 25 years, whereas his elder sister, sharing the same mutation but showing less severe biochemical, neuroimaging and ocular motor parameters, presented with a similar schizophrenia-like illness with associated cognitive and motor disturbance at age 31 years. Their illness onset, course and response to treatment mirrors the sex dimorphism seen in schizophrenia, and is suggestive of an interaction between the neurobiology of their metabolic disorder and sex differences in neurodevelopment.

Spatial working memory (SWM) dysfunction has been suggested as a trait marker of schizophrenia and implicates a diffuse network involving prefrontal, temporal and parietal cortices. However, structural abnormalities in both grey and white matter in relation to SWM deficits are largely unexplored. The current magnetic resonance imaging (MRI) study examined this relationship in a sample of young first-episode schizophrenia (FES) patients using a whole-brain voxel-based method. SWM ability of 21 FES patients and 41 comparable controls was assessed by the CANTAB SWM task. Using an automated morphometric analysis of brain MRI scans, we assessed the relationship between SWM abilities and both grey matter volume and white matter density in both groups. Our findings demonstrated the different directionality of the association between SWM errors and grey matter volume in left frontal regions and white matter tracts connecting these regions with temporal and occipital areas between FES patients and controls. This suggests that the substrate underpinning the normal variability in SWM function in healthy individuals may be abnormal in FES, and that the normal neurodevelopmental processes that drive the development of SWM networks are disrupted in schizophrenia.

Objective: Young patients with frontotemporal dementia (FTD) may present with schizophrenia-like psychosis. Few studies have investigated whether FTD-like neuropathological changes are present in schizophrenia. The purpose of the present study was therefore to determine whether FTD-like abnormalities in TARDNA binding protein (TDP-43) and ubiquitin are detectable in hippocampal dentate gyrus of patients with schizophrenia and bipolar disorder. A secondary objective was to identify clinicopathological relationships of any such abnormalities., Methods: Hippocampal sections from 12 patients (nine with schizophrenia and three with bipolar disorder) and 11 control subjects Facility from the National Neural Tissue Resource Centre, Melbourne were blindly rated for the presence or absence of normal TDP-43 staining or ubiquitin-positive neuronal inclusions within the dentate gyrus. The clinical files of all subjects were reviewed for demographic and clinical information., Results: In three patients the normal expression of nuclear TDP-43 staining was not detected. Significantly, all three subjects presented after the age of 50 and had an adult child diagnosed with the same psychiatric disorder., Conclusion: Abnormalities in TDP-43 nuclear expression were identified in patients with late-onset psychosis and a positive family history.

Reductions in the size of the anterior callosum have been described for both first-episode and established schizophrenia and bipolar affective disorder, but never in individuals with psychotic bipolar disorder. We recruited 110 first-episode psychosis subjects (74 schizophrenia spectrum and 36 affective psychosis) and 36 age- and gender-matched controls. The callosum was extracted from a mid-sagittal slice from T1-weighted magnetic resonance images, and total area, length and curvature of the callosum were compared. The schizophrenia-spectrum group showed reductions in thickness of the genu across schizophreniform and schizoaffective disorder and schizophrenia, and the schizoaffective disorder group also showed an increase in thickness in the splenium and isthmus. None of these changes were seen in the affective disorder group, although a non-significant increase in the region of the isthmus and splenium was seen, particularly in the depressed group. Psychotic affective disorders do not show the anterior callosal reductions that are seen in the schizophrenia-spectrum group at first episode. The schizoaffective patients show additional posterior callosal expansions that may be a marker of an affective diathesis. This suggests that schizoaffective disorder may represent two interacting illness processes or be mid-way along a continuum of these two broad categories of illness at first psychosis.

Background: Few studies have investigated the relationship between schizophrenia and frontotemporal dementia., Aims: To investigate this relationship through a clinicopathological investigation of young-onset frontotemporal dementia and a review of the case literature., Method: Cases of young-onset frontotemporal dementia were identified within the local brain bank. The clinical course and pathological findings were collated. For the literature review, cases of frontotemporal dementia identified through Medline were selected according to defined criteria. The demographic, clinical, pathological and genetic characteristics of cases presenting with a psychotic illness were identified., Results: In the case series, 5 of 17 patients with frontotemporal dementia had presented with a psychotic illness (schizophrenia/schizoaffective disorder n=4, bipolar disorder n=1) an average of 5 years prior to the dementia diagnosis. Patients with schizophrenia exhibited changes consistent with TDP-43 and ubiquitin-positive frontotemporal dementia. In the cases review, a third of patients aged 30 years or under and a quarter of those aged 40 years or under had been diagnosed with psychosis at presentation., Conclusions: Patients with young-onset frontotemporal dementia may be diagnosed with a psychotic illness years before the dementia diagnosis is made. These findings have implications for clinicians and for our further understanding of the neurobiology of psychotic illness.

Reductions in the size of the anterior callosum have been described for both first-episode schizophrenia-spectrum psychosis and established schizophrenia, but have not been examined in individuals at ultra-high risk for psychosis (UHR). We compared 100 UHR individuals (27 of whom later developed psychosis) with 38 age-matched control subjects on measures of size and shape of the corpus callosum to determine if changes previously demonstrated in first-episode and established schizophrenia are present in the pre-psychotic phase. Each individual's callosum was extracted from the mid-sagittal slice from T1-weighted magnetic resonance images, and total area, length and curvature of the callosum was compared using one-way ANOVA, and 39 regional thicknesses via a non-parametric permutation method to account for non-independence of adjacent measures. Total area, length and curvature did not differ between the groups. Compared to both the UHR-NP group and controls, the UHR-P group showed significant regional reductions in the region of the anterior genu of the callosum. The UHR-NP group did not differ from controls. Positive and negative symptoms did not affect regional thickness in either of the patient groups. Cox regression showed that mean anterior genu thickness was highly predictive of a transition to psychosis. Reductions in the thickness of the anterior callosum differentiate between high-risk individuals who transition to psychosis and those who do not, and is highly predictive of transition. These changes may reflect primary pathology of orbitofrontal and medial frontal cortex, or deficits in anterior interhemispheric myelination.

Background: The shape of the corpus callosum may differ in schizophrenia, although no study has compared first-episode with established illness., Aims: To investigate the size and shape of the corpus callosum in a large sample of people with first-episode and established schizophrenia., Method: Callosal size and shape were determined using high-resolution magnetic resonance imaging on 76 patients with first-episode schizophrenia-spectrum disorders, 86 patients with established schizophrenia and 55 healthy participants., Results: There were no significant differences in total area across groups. Reductions in callosal width were seen in the region of the anterior genu in first-episode disorder (P<0.005). Similar reductions were seen in the chronic schizophrenia group in the anterior genu, but also in the posterior genu and isthmus (P=0.0005)., Conclusions: Reductions in anterior callosal regions connecting frontal cortex are present at the onset of schizophrenia, and in established illness are accompanied by changes in other regions of the callosum connecting cingulate, temporal and parietal cortices.

Diffusion Tensor Imaging (DTI) investigations in schizophrenia have provided evidence of impairment in white matter as indicated by reduced fractional anisotropy (FA). However, the neuropathological implications of these findings remain unclear. In the current study, we conducted a voxelwise analysis of the constituent parameters of FA, Axial (lambda(||)) and Radial Diffusivity (lambda( upper left and right quadrants)), in 14 male participants with schizophrenia and 14 age, gender, education, and premorbid intelligence matched healthy controls. Significantly reduced FA and higher Radial Diffusivity were concurrently observed in several major white matter tracts in the schizophrenia group. This finding suggests that the loss of white matter integrity in schizophrenia is the result of demyelination and/or changes to the axonal cytoskeleton rather than gross axonal damage.

We describe the case of a 23-year-old Caucasian woman who presented with alien hand syndrome and a first episode of the coenesthetic subtype of schizophrenia. 'Alienness' of her non-dominant hand was intimately phenomenologically associated with the onset of first-psychosis. Cerebral MRI revealed a partial agenesis of the corpus callosum with a complete absence of the rostrum, hypoplastic anterior and inferior genu, and a hypoplastic splenium. This case suggests that this syndrome can occur with the development of a functional disconnection syndrome involving the anterior callosum, and in this case the 'second hit' proposed to occur in early adulthood in schizophrenia may have interacted with her earlier neurodevelopmental lesion to result in a combination of psychosis and alien hand syndrome., (2008 S. Karger AG, Basel.)

Psychotic symptoms occur in a variety of medical and neurological conditions. The authors describe three young men with a variant form of Niemann-Pick type C disease, a neurodegenerative disorder related to abnormal intracellular cholesterol metabolism, who presented with psychosis in early adulthood. Two patients were treated for schizophrenia for many years prior to a diagnosis of Niemann-Pick type C. The cases presented in this article illustrate the role of changes in both white and gray matter structures in psychosis, and, like the assessments of other neurodevelopmental disorders that predispose toward psychotic presentations, shed light on the underlying pathophysiology of major mental disorders.

A wide range of neuropathological abnormalities have been detected in schizophrenia sufferers, and emerging evidence points to neural substrates of connectivity as having a key role in the development of disease. This article reviews the available evidence for white matter pathology in schizophrenia, and examines its possible role as a substrate of impaired connectivity. Neuropathological data is suggestive of abnormalities in glial structure and function, and myelinated structures have also been implicated. A number of studies, particularly using gene array technology, are pointing towards significant disruption in expression of myelination genes. Magnetic resonance imaging has tended to focus on, and detect, more grey than white matter abnormalities, although non-volumetric techniques are suggestive of changes in the microstructure of white matter in schizophrenia. Myelinated structures are an attractive candidate for an anatomical substrate for disconnectivity, and may act synergistically with synaptic changes to result in functional disconnectivity although the relationship between white and grey matter changes in the illness remains unclear.

Objective: To analyse the available data regarding the presentation of psychosis in diseases of central nervous system (CNS) white matter., Method: The available neurological and psychiatric literature on developmental, neoplastic, infective, immunological and other white matter diseases was reviewed., Results: A number of diseases of the white matter can present as schizophrenia-like psychoses, including leukodystrophies, neoplasms, velocardiofacial syndrome, callosal anomalies and inflammatory diseases., Conclusions: Production of psychotic symptoms may result from functional asynchrony of interdependent regions, due to alterations in critical circuits as a result of pathology. The nature, location and timing of white matter pathology seem to be the key factors in the development of psychosis, especially during the critical adolescent period of association area myelination. Diseases that disrupt the normal formation of myelin appear to cause psychosis at higher rates than those that disrupt mature myelinated structures. Diffuse rather than discrete lesions, in particular those affecting frontotemporal zones, are also more strongly associated with schizophrenia-like psychosis. These illnesses point to the central role that white matter plays in maintaining CNS connectivity and to how pathology of the white matter may contribute to the neurobiology of psychosis.

Objective: To determine the nature of the relationship between schizophrenia-like psychosis and narcolepsy., Background: A relationship between schizophrenia and narcolepsy has long been postulated due to the association of schizophrenia-like psychosis with narcolepsy and its treatment., Method: We report two patients who presented with schizophrenia-like psychosis of narcolepsy and review the literature regarding possible shared neurobiology between the two disorders that might explain their co-occurrence., Results: There appears to be little in the way of common pathology between these two conditions when symptoms, human leukocyte antigen associations, rapid eye movement sleep architecture, D2-dopamine receptor changes, and hypocretinergic function are examined., Conclusions: The available literature suggests that schizophrenia-like psychosis in narcolepsy is most commonly medication related or a chance co-occurrence, with limited evidence for a separate psychosis of narcolepsy.