White matter microstructural abnormalities in patients with late-onset schizophrenia identified by a voxel-based diffusion tensor imaging

Serum S100B protein and white matter changes in schizophrenia before and after medication

Schizophrenia patients have abnormalities in white matter (WM) integrity in brain regions. S100B has been shown to be a marker protein for glial cells. The atypical antipsychotics have neuroprotective effects on the brain. It is not clear whether antipsychotics can induce S100B changes and improve symptoms by protecting oligodendrocytes. To investigate WM and S100B changes and associations and determine the effect of quetiapine on WM and S100B in schizophrenia patients, we determined serum S100B levels with solid phase immunochromatography and fractional anisotropy（FA）values of 36 patients and 40 healthy controls. Patients exhibited significantly higher serum concentrations of S100B and decreased FA values in left postcentral，right superior frontal，right thalamus, and left inferior occipital gyrus, while higher in right temporal cortex WM compared with healthy controls. Following treatment with quetiapine, patients had decreased S100B and higher FA values in right cerebellum，right superior frontal，right thalamus, and left parietal cortex，and decreased FA values in right temporal cortex WM compared with pre-treatment values. Furthermore, S100B were negatively correlated with PANSS positive scores and positively correlated with FA values in the left postcentral cortex. In addition，the percentage change in FA values in the right temporal cortex was positively correlated with the percentage change in the S100B, percentage reduction in PANSS scores, and percentage reduction in PANSS-positive scores. Our findings demonstrated abnormalities in S100B and WM microstructure in patients with schizophrenia. These abnormalities may be partly reversed by quetiapine treatment.

Overview of late-onset psychoses

BACKGROUND

Several etiologies can underlie the development of late-onset psychosis, defined by first psychotic episode after age 40 years. Late-onset psychosis is distressing to patients and caregivers, often difficult to diagnose and treat effectively, and associated with increased morbidity and mortality.

METHODS

The literature was reviewed with searches in Pubmed, MEDLINE, and the Cochrane library. Search terms included "psychosis," "delusions," hallucinations," "late onset," "secondary psychoses," "schizophrenia," bipolar disorder," "psychotic depression," "delirium," "dementia," "Alzheimer's," "Lewy body," "Parkinson's, "vascular dementia," and "frontotemporal dementia." This overview covers the epidemiology, clinical features, neurobiology, and therapeutics of late-onset psychoses.

RESULTS

Late-onset schizophrenia, delusional disorder, and psychotic depression have unique clinical characteristics. The presentation of late-onset psychosis requires investigation for underlying etiologies of "secondary" psychosis, which include neurodegenerative, metabolic, infectious, inflammatory, nutritional, endocrine, and medication toxicity. In delirium, psychosis is common but controlled evidence is lacking to support psychotropic medication use. Delusions and hallucinations are common in Alzheimer's disease, and hallucinations are common in Parkinson's disease and Lewy body dementia. Psychosis in dementia is associated with increased agitation and a poor prognosis. Although commonly used, no medications are currently approved for treating psychosis in dementia patients in the USA and nonpharmacological interventions need consideration.

CONCLUSION

The plethora of possible causes of late-onset psychosis requires accurate diagnosis, estimation of prognosis, and cautious clinical management because older adults have greater susceptibility to the adverse effects of psychotropic medications, particularly antipsychotics. Research is warranted on developing and testing efficacious and safe treatments for late-onset psychotic disorders.

Microstructural abnormalities in callosal fibers and their relationship with cognitive function in schizophrenia: A tract-specific analysis study

INTRODUCTION

The corpus callosum serves the essential role of relaying cognitive information between the homologous regions in the left and the right hemispheres of the brain. Cognitive impairment is a core dysfunction of schizophrenia, but much of its pathophysiology is unknown. The aim of this study was to elucidate the association between microstructural abnormalities of the corpus callosum and cognitive dysfunction in schizophrenia.

METHODS

We examined stepwise multiple regression analysis to investigate the relationship of the fractional anisotropy (FA) of callosal fibers in each segment with z-scores of each brief assessment of cognition in schizophrenia subtest and cognitive composite score in all subjects (19 patients with schizophrenia [SZ group] and 19 healthy controls [HC group]). Callosal fibers were separated into seven segments based on their cortical projection using tract-specific analysis of diffusion tensor imaging.

RESULTS

The FA of callosal fibers in the temporal segment was significantly associated with z-scores of token motor test, Tower of London test, and the composite score. In the SZ group, the FA of callosal fibers in the temporal segment was significantly associated with the z-score of the Tower of London test. In addition, the FA of callosal fibers in temporal segment showed significant negative association with the positive and negative syndrome scale negative score in the SZ group. Compared to the HC group, the FA in temporal segment was significantly decreased in the SZ group.

CONCLUSION

Our results suggest that microstructural abnormalities in the callosal white matter fibers connecting bilateral temporal lobe cortices contribute to poor executive function and severe negative symptom in patients with schizophrenia.

Late-onset psychosis and very-late-onset-schizophrenia-like-psychosis: an updated systematic review

Psychotic disorders have long been known to be a condition that peaks during adolescence and early adulthood. A considerable proportion of patients have their first onset at or after the age of 40, but little is known about this population. The current systematic review examined the clinical presentation of late-onset psychosis (LOP) and very-late-onset-schizophrenia-like psychosis (VLOSLP) with focus on their psychopathological, neuropsychological, neurobiological, psychosocial and psychological correlates. A systematic search of studies published from 2000 to 2019 from Cochrane Library, Pubmed, Medline, Embase, PsycINFO, and Scopus yielded 27 original studies that were included in this review. Results revealed there is a dearth of empirical research on the conditions in the current literature and inconsistencies in the findings reported may be associated with the lack of uniformity in the definitions for LOP and VLOSLP. Future research on the topic shall (i) specify the onset age criteria for LOP and VLOSLP; (ii) study the conditions independently; (iii) involve a larger sample size, and iv) account for potential confounding variables. A comprehensive evaluation of the risks and benefits of pharmacological treatment may also be needed.

Psychotic disorders in late life: a narrative review

Psychotic disorders are not uncommon in late life. These disorders often have varied etiologies, different clinical presentations, and are associated with significant morbidity and mortality among the older adult population. Psychotic disorders in late life develop due to the complex interaction between various biological, psychological, social, and environmental factors. Given the significant morbidity and mortality associated with psychotic disorders in late life, a comprehensive work-up should be conducted when they are encountered. The assessment should not only identify the potential etiologies for the psychotic disorders, but also recognize factors that predicts possible outcomes for these disorders. Treatment approaches for psychotic disorders in late life should include a combination of nonpharmacological management strategies with the judicious use of psychotropic medications. When antipsychotic medications are necessary, they should be used cautiously with the goal of optimizing outcomes with regular monitoring of their efficacy and adverse effects.

White matter and schizophrenia: A meta-analysis of voxel-based morphometry and diffusion tensor imaging studies

Voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) are the most implemented methodologies to detect alterations of both gray and white matter (WM). However, the role of WM in mental disorders is still not well defined. We aimed at clarifying the role of WM disruption in schizophrenia and at identifying the most frequently involved brain networks. A systematic literature search was conducted to identify VBM and DTI studies focusing on WM alterations in patients with schizophrenia compared to control subjects. We selected studies reporting the coordinates of WM reductions and we performed the anatomical likelihood estimation (ALE). Moreover, we labeled the WM bundles with an anatomical atlas and compared VBM and DTI ALE-scores of each significant WM tract. A total of 59 studies were eligible for the meta-analysis. WM alterations were reported in 31 and 34 foci with VBM and DTI methods, respectively. The most occurred WM bundles in both VBM and DTI studies and largely involved in schizophrenia were long projection fibers, callosal and commissural fibers, part of motor descending fibers, and fronto-temporal-limbic pathways. The meta-analysis showed a widespread WM disruption in schizophrenia involving specific cerebral circuits instead of well-defined regions.

Adverse effects of metallic artifacts on voxel-wise analysis and tract-based spatial statistics in diffusion tensor imaging

Background Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that reflects the Brownian motion of water molecules constrained within brain tissue. Fractional anisotropy (FA) is one of the most commonly measured DTI parameters, and can be applied to quantitative analysis of white matter as tract-based spatial statistics (TBSS) and voxel-wise analysis. Purpose To show an association between metallic implants and the results of statistical analysis (voxel-wise group comparison and TBSS) for fractional anisotropy (FA) mapping, in DTI of healthy adults. Material and Methods Sixteen healthy volunteers were scanned with 3-Tesla MRI. A magnetic keeper type of dental implant was used as the metallic implant. DTI was acquired three times in each participant: (i) without a magnetic keeper (FAnon1); (ii) with a magnetic keeper (FAimp); and (iii) without a magnetic keeper (FAnon2) as reproducibility of FAnon1. Group comparisons with paired t-test were performed as FAnon1 vs. FAnon2, and as FAnon1 vs. FAimp. Results Regions of significantly reduced and increased local FA values were revealed by voxel-wise group comparison analysis (a P value of less than 0.05, corrected with family-wise error), but not by TBSS. Conclusion Metallic implants existing outside the field of view produce artifacts that affect the statistical analysis (voxel-wise group comparisons) for FA mapping. When statistical analysis for FA mapping is conducted by researchers, it is important to pay attention to any dental implants present in the mouths of the participants.

Effects of a Polymorphism of the Neuronal Amino Acid Transporter SLC6A15 Gene on Structural Integrity of White Matter Tracts in Major Depressive Disorder

Background

The SLC6A15 gene has been identified as a novel candidate gene for major depressive disorder (MDD). It is presumed to be involved in the pathophysiology of MDD through regulation of glutamate transmission in the brain. However, the involvement of this gene in microstructural changes in white matter (WM) tracts remains unclear. We aimed to investigate the influence of a polymorphism of this gene (rs1545853) on the structural integrity of WM tracts in the cortico-limbic network.

Methods

Eighty-six patients with MDD and 64 healthy controls underwent T1-weighted structural magnetic resonance imaging, including diffusion tensor imaging (DTI), and genotype analysis. We selected the genu of the corpus callosum, the uncinate fasciculus, cingulum, and fornix as regions of interest, and extracted fractional anisotropy (FA) values using the FMRIB Diffusion Toolbox software.

Results

FA values for the left parahippocampal cingulum (PHC) was significantly reduced in the patients with MDD compared to healthy control participants (p = 0.004). We also found that MDD patients with the A allele showed reduced FA values for the left PHC than did healthy controls with the A allele (p = 0.012). There was no significant difference in the FA value of left PHC for the comparison between the G homozygotes of MDD and healthy control group.

Conclusions

We observed an association between the risk allele of the SLC6A15 gene rs1545843 and the WM integrity of the PHC in MDD patients, which is known to play an important role in the neural circuit involved in emotion processing.

Psychosis in Later Life: A Review and Update

Psychosis is relatively common in later life and can present in a wide variety of contexts, including early-onset and late-onset schizophrenia, delusional disorder, mood disorders, and various dementias. It can also occur as the result of numerous medical and neurological diseases and from the use of certain medications. Although identifying the cause of psychosis in older patients can be challenging, the unique clinical features associated with the different disorders can help in making the diagnosis. Accurate diagnosis of psychosis in older populations is essential, as its treatment varies depending on the context in which it appears. Despite the safety concerns regarding the use of antipsychotics in older patients, certain pharmacological treatments appear to be both efficacious and reasonably safe in treating psychosis in older populations. Additionally, although research is limited, numerous psychosocial therapies appear promising. This review summarizes the literature on the epidemiology, clinical characteristics, neuroimaging, and treatment of psychosis in later life, and serves as an update to past reviews on this topic.

The myelinated fiber loss in the corpus callosum of mouse model of schizophrenia induced by MK-801

Previous magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) investigations have shown that the white matter volume and fractional anisotropy (FA) were decreased in schizophrenia (SZ), which indicated impaired white matter integrity in SZ. However, the mechanism underlying these abnormalities has been less studied. The current study was designed to investigate the possible reasons for white matter abnormalities in the mouse model of SZ induced by NMDA receptor antagonist using the unbiased stereological methods and transmission electron microscope technique. We found that the mice treated with MK-801 demonstrated a series of schizophrenia-like behaviors including hyperlocomotor activity and more anxiety. The myelinated fibers in the corpus callosum (CC) of the mice treated with MK-801 were impaired with splitting lamellae of myelin sheaths and segmental demyelination. The CC volume and the total length of the myelinated fibers in the CC of the mice treated with MK-801 were significantly decreased by 9.4% and 16.8% when compared to those of the mice treated with saline. We further found that the loss of the myelinated fibers length was mainly due to the marked loss of the myelinated nerve fibers with the diameter of 0.4-0.5 μm. These results indicated that the splitting myelin sheaths, demyelination and the loss of myelinated fibers with small diameter might provide one of the structural bases for impaired white matter integrity of CC in the mouse model of SZ. These results might also provide a baseline for further studies searching for the treatment of SZ through targeting white matter.

The reduction of volume and fiber bundle connections in the hippocampus of EGR3 transgenic schizophrenia rats

BACKGROUND AND OBJECTIVE

There is a growing consensus that schizophrenia is ultimately caused by abnormal communication between spatially disparate brain structures. White matter fasciculi represent the primary infrastructure for long distance communication in the brain. In this study, we aimed to investigate the white matter connection in schizophrenia susceptible brain regions of early growth response factor 3 (EGR3) expressing rats.

METHODS

A rat model of schizophrenia was created by the transfection of the EGR3 gene into rat hippocampus. All animals were placed in a fixation system using a commercial rat-dedicated coil. Schizophrenia susceptible brain regions were scanned using in vivo diffusion tensor magnetic resonance imaging. The volume, quantity, average length of fiber bundles, fractional anisotropy, apparent diffusion coefficient, the relative heterosexual fraction, and volume ratio were collected in the whole brain and schizophrenia related brain areas (the hippocampus, thalamus, and prefrontal lobe). MedINRIA software was used for data processing of diffusion tensor and fiber bundles tracking. The fibronectin in relevant brain regions was also analyzed.

RESULTS

There was a significant decrease in the volume of the fiber beam through the left hippocampus dentate in the schizophrenia model group in comparison to the control group and the risperidone treatment group (P<0.05). A significant reduction in the volume and number of the fiber bundles was also observed in left prefrontal-left hippocampus, left hippocampus-left thalamus, left prefrontal-left hippocampus-left thalamus areas in the model group (all P<0.05).

CONCLUSION

The volume of hippocampus and the number of fiber bundles were reduced in EGR3 transgenic schizophrenia rats, and are the most sensitive indicators in schizophrenia. The diffusion tensor imaging technique plays an important role in the evaluation of patients with schizophrenia.

Effect of clozapine on white matter integrity in patients with schizophrenia: a diffusion tensor imaging study

Several diffusion tensor imaging (DTI) studies have reported disturbed white matter integrity in various brain regions in patients with schizophrenia, whereas only a few studied the effect of antipsychotics on DTI measures. The aim of this study was to investigate the effect of 12 weeks of clozapine treatment on DTI findings in patients with schizophrenia, and to compare the findings with those in unaffected controls. The study included 16 patients with schizophrenia who were assessed with the Positive and Negative Syndrome Scale, a neurocognitive test battery, and DTI at baseline and 12 weeks after the initiation of clozapine treatment. Eight unaffected controls were assessed once with the neurocognitive test battery and DTI. Voxel-wise analysis of DTI data was performed via tract-based spatial statistics (TBSS). Compared with the control group, the patient group exhibited lower fractional anisotropy (FA) in 16 brain regions, including the bilateral superior longitudinal fasciculi, inferior fronto-occipital fasciculi, superior and inferior parietal lobules, cingulate bundles, cerebellum, middle cerebellar peduncles, and left inferior longitudinal fasciculus, whereas the patients had higher FA in six regions, including the right parahippocampus, left anterior thalamic radiation, and right posterior limb of the internal capsule before clozapine treatment. After 12 weeks of treatment with clozapine, white matter FA was increased in widespread brain regions. In two of the regions where FA had initially been lower in patients compared with controls (left inferior fronto-occipital fasciculus and superior parietal lobule), clozapine appeared to increase FA. An improvement in semantic fluency was correlated with the increase in FA value in the left inferior fronto-occipital fasciculus. An increase in FA following 12 weeks of treatment with clozapine suggests that this treatment alters white matter microstructural integrity in patients with schizophrenia previously treated with typical and/or atypical antipsychotics and, in some locations, reverses a previous deficit.

Advances in neuroimaging research of schizophrenia in China

SUMMARY

Since Hounsfield's first report about X-ray computed tomography (CT) in 1972, there has been substantial progress in the application of neuroimaging techniques to study the structure, function, and biochemistry of the brain. This review provides a summary of recent research in structural and functional neuroimaging of schizophrenia in China and four tables describing all of the relevant studies from mainland China. The first research report using neuroimaging techniques in China dates back to 1983, a study that reported encephalatrophy in 30% of individuals with schizophrenia. Functional neuroimaging research in China emerged in the 1990s and has undergone rapid development since. Recently, structural and functional brain networks has become a hot topic among China's neuroimaging researchers.

Late-onset schizophrenia: do recent studies support categorizing LOS as a subtype of schizophrenia?

PURPOSE OR REVIEW

To review recent literature about late-onset schizophrenia (LOS): schizophrenia with onset between ages 40 and 60 years. New findings are presented in the context of the previous literature.

RECENT FINDINGS

Newer studies continue to suggest that early-onset schizophrenia (EOS) and LOS share fundamental clinical features (i.e., positive symptoms, negative symptoms, functional deficits). One larger recent study confirmed earlier findings that LOS differs from EOS in several important ways, including predominance of women, lower severity of positive symptoms, and lower average antipsychotic dose requirement. However, this study did not find LOS patients were more likely to have the paranoid subtype or to have less severe negative symptoms compared with EOS patients. New neuroimaging and molecular studies are identifying possible differences in the underlying pathophysiology of EOS and schizophrenia developing in mid-life to late-life; however, more research is needed to confirm these findings and determine their significance. No studies evaluated treatment strategies specifically in LOS.

SUMMARY

LOS continues to be an understudied area. Recent studies add support to the idea that LOS may be a distinct subtype of schizophrenia. Studies designed to elucidate the pathophysiology of LOS in comparison with EOS and to assess treatment strategies in this population are needed.

FKBP5 genotype and structural integrity of the posterior cingulum

Alterations in the microarchitecture of the posterior cingulum (PC), a white matter tract proximal to the hippocampus that facilitates communication between the entorhinal and cingulate cortices, have been observed in individuals with psychiatric disorders, such as depression and post-traumatic stress disorder (PTSD). PC decrements may be a heritable source of vulnerability for the development of affective disorders; however, genetic substrates for these white matter abnormalities have not been identified. The FKBP5 gene product modulates glucocorticoid receptor function and has been previously associated with differential hippocampal structure, function, and affect disorder risk. Thus, FKBP5 is an attractive genetic target for investigations of PC integrity. We examined associations between PC integrity, measured through diffusion tensor imaging (DTI) and fractional anisotropy (FA; an index of white matter integrity), and polymorphisms in the FKBP5 SNP rs1360780 in a sample of 82 traumatized female civilians. Findings indicated that, compared with individuals without this allele, individuals who carried two 'risk' alleles for this FKBP5 SNP (T allele; previously associated with mood and anxiety disorder risk) demonstrated significantly lower FA in the left PC, even after statistically controlling for variance associated with age, trauma exposure, and PTSD symptoms. These data suggest that specific allelic variants for an FKBP5 polymorphism are associated with decrements in the left PC microarchitecture. These white matter abnormalities may be a heritable biological marker that indicates increased vulnerability for the development of psychiatric disorders, such as PTSD.

Neuroimaging findings in late-onset schizophrenia and bipolar disorder

In recent years, there has been an increasing interest in late-onset mental disorders. Among them, geriatric schizophrenia and bipolar disorder are significant health care risks and major causes of disability. We discussed whether late-onset schizophrenia (LOS) and late-onset bipolar (LOB) disorder can be a separate entity from early-onset schizophrenia (EOS) and early-onset bipolar (EOB) disorder in a subset of late-life schizophrenia or late-life bipolar disorder through neuroimaging studies. A literature search for imaging studies of LOS or LOB was performed in the PubMed database. Search terms used were "(imaging OR MRI OR CT OR SPECT OR DTI OR PET OR fMRI) AND (schizophrenia or bipolar disorder) AND late onset." Articles that were published in English before October 2013 were included. There were a few neuroimaging studies assessing whether LOS and LOB had different disease-specific neural substrates compared with EOS and EOB. These researches mainly observed volumetric differences in specific brain regions, white matter hyperintensities, diffusion tensor imaging, or functional neuroimaging to explore the differences between LOS and LOB and EOS and EOB. The aim of this review was to highlight the neural substrates involved in LOS and LOB through neuroimaging studies. The exploration of neuroanatomical markers may be the key to the understanding of underlying neurobiology in LOS and LOB.

Clinical features of late-onset schizophrenia in Japan: comparison with early-onset cases

BACKGROUND

Although the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders abandoned the use of the specifier 'late-onset', a considerable number of studies have reported clinical characteristics of late-onset schizophrenia. Still, only limited research has been conducted on late-onset schizophrenia, especially in Asian countries. In this epidemiological study, the clinical characteristics of late-onset schizophrenia were examined in comparison with early-onset schizophrenia.

METHODS

All patients with schizophrenia admitted to the psychiatric ward of Jichi Medical University Hospital between 1 April 1993 and 31 March 2006 were divided into two groups according to age at first onset: ≥40 years (late-onset group) and <40 years (early-onset group). The sex ratio, presence or absence of depression, schizophrenia subtype, premorbid character, marital history, and employment history at first onset were compared between the two groups.

RESULTS

Of the 316 patients with schizophrenia identified, 38 patients were assigned to the late-onset group and 278 patients to the early-onset group. Mean age at onset was 23.9 ± 8.2 years for all men and 28.0 ± 13.5 years for all women. The late-onset group was characterized by more women, more paranoid type, more depressive symptoms, less introverted premorbid character, better premorbid adaptation and less neuroleptics.

CONCLUSION

The characteristics of late-onset schizophrenia in Japan are in line those reported previously.

Memory deficits in late-onset schizophrenia

Late-onset schizophrenia (LOS) is a controversial diagnosis, mainly characterized by more positive symptoms and less deterioration. LOS could be considered as either an extreme of typical schizophrenia (but for old age patients, and short duration of the disorder), or an independent group of patients with a specific diagnosis, with no clear evidence in favor or against any of these hypotheses. The aim of the present study is to characterize the memory cognitive profile of LOS patients without related organic factors (N=25), compared to early-onset schizophrenic patients (EOS, N=44), matched for the duration of the disorder, and healthy controls (HC, N=23), matched for the age of patients. Lifetime clinical symptoms and functioning were collected using the DIGS and the PANSS, and components of memory capacity were assessed with the Forward and Backward Digit Span Tasks, Rey Complex Figure and Verbal Fluency Tests. LOS patients were performing significantly better than EOS patients on the digit span task, Rey's complex figure at T1 score and phonemic verbal fluency. However, LOS had significantly lower performances than healthy controls on the digit span task and on both verbal fluency tests. This study provides evidence that LOS had intermediate outcome compared to EOS and controls. LOS can therefore be in line with a dimensional clinical approach of schizophrenia, whereby it presents few memory deficits and few disorganization and negative symptoms with mostly positive symptoms and possibly etiopathogenic specificities. Further studies including more specific memory assessment tests and larger samples are needed to confirm the present finding.

Vestibular insights into cognition and psychiatry

The vestibular system has traditionally been thought of as a balance apparatus; however, accumulating research suggests an association between vestibular function and psychiatric and cognitive symptoms, even when balance is measurably unaffected. There are several brain regions that are implicated in both vestibular pathways and psychiatric disorders. The present review examines the anatomical associations between the vestibular system and various psychiatric disorders. Despite the lack of direct evidence for vestibular pathology in the key psychiatric disorders selected for this review, there is a substantial body of literature implicating the vestibular system in each of the selected psychiatric disorders. The second part of this review provides complimentary evidence showing the link between vestibular dysfunction and vestibular stimulation upon cognitive and psychiatric symptoms. In summary, emerging research suggests the vestibular system can be considered a potential window for exploring brain function beyond that of maintenance of balance, and into areas of cognitive, affective and psychiatric symptomology. Given the paucity of biological and diagnostic markers in psychiatry, novel avenues to explore brain function in psychiatric disorders are of particular interest and warrant further exploration.