Gray matter volume deficits and correlation with insight and negative symptoms in first-psychotic-episode subjects

Voxel-based morphometry for separation of schizophrenia from other types of psychosis in first episode psychosis

BACKGROUND

Schizophrenia is a psychiatric disorder which involves distortions in thought and perception, blunted affect, and behavioural disturbances. The longer psychosis goes unnoticed and untreated, the more severe the repercussions for relapse and recovery. There is some evidence that early intervention services can help, and diagnostic techniques that could contribute to early intervention may offer clinical utility in these situations. The index test being evaluated in this review is the structural magnetic resonance imaging (MRI) analysis technique known as voxel-based morphometry (VBM) that estimates the distribution of grey matter tissue volume across several brain regions. This review is an exploratory examination of the diagnostic 'potential' of VBM for use as an additional tool in the clinical examination of patients with first episode psychosis to establish whether an individual will progress on to developing schizophrenia as opposed to other types of psychosis.

OBJECTIVES

To determine whether VBM applied to the brain can be used to differentiate schizophrenia from other types of psychosis in participants who have received a clinical diagnosis of first episode psychosis.

SEARCH METHODS

In December 2013, we updated a previous search (May 2012) of MEDLINE, EMBASE, and PsycInfo using OvidSP.

SELECTION CRITERIA

We included retrospective and prospective studies that consecutively or randomly selected adolescent and adult participants (< 45 years) with a first episode of psychosis; and that evaluated the diagnostic accuracy of VBM for differentiating schizophrenia from other psychoses compared with a clinical diagnosis made by a qualified mental health professional, with or without the use of standard operational criteria or symptom checklists. We excluded studies in children, and in adult participants with organic brain disorders or who were at high risk for schizophrenia, such as people with a genetic predisposition.

DATA COLLECTION AND ANALYSIS

Two review authors screened all references for inclusion. We assessed the quality of studies using the QUADAS-2 instrument. Due to a lack of data, we were not able to extract 2 x 2 data tables for each study nor undertake any meta-analysis.

MAIN RESULTS

We included four studies with a total of 275 participants with first episode psychosis. VBM was not used to diagnose schizophrenia in any of the studies, instead VBM was used to quantify the magnitude of differences in grey matter volume. Therefore, none of the included studies reported data that could be used in the analysis, and we summarised the findings narratively for each study.

AUTHORS' CONCLUSIONS

There is no evidence to currently support diagnosing schizophrenia (as opposed to other psychotic disorders) using the pattern of brain changes seen in VBM studies in patients with first episode psychosis. VBM has the potential to discriminate between diagnostic categories but the methods to do this reliably are currently in evolution. In addition, the lack of applicability of the use of VBM to clinical practice in the studies to date limits the usefulness of VBM as a diagnostic aid to differentiate schizophrenia from other types of psychotic presentations in people with first episode of psychosis.

Neurobiology of insight deficits in schizophrenia: An fMRI study

Prior research has shown insight deficits in schizophrenia to be associated with specific neuroimaging changes (primarily structural) especially in the prefrontal sub-regions. However, little is known about the functional correlates of impaired insight. Seventeen patients with schizophrenia (mean age 40.0±10.3; M/F=14/3) underwent fMRI on a Philips 3.0 T Achieva system while performing on a self-awareness task containing self- vs. other-directed sentence stimuli. SPM5 was used to process the imaging data. Preprocessing consisted of realignment, coregistration, and normalization, and smoothing. A regression analysis was used to examine the relationship between brain activation in response to self-directed versus other-directed sentence stimuli and average scores on behavioral measures of awareness of symptoms and attribution of symptoms to the illness from Scale to Assess Unawareness of Mental Disorders. Family Wise Error correction was employed in the fMRI analysis. Average scores on awareness of symptoms (1=aware; 5=unaware) were associated with activation of multiple brain regions, including prefrontal, parietal and limbic areas as well as basal ganglia. However, average scores on correct attribution of symptoms (1=attribute; 5=misattribute) were associated with relatively more localized activation of prefrontal cortex and basal ganglia. These findings suggest that unawareness and misattribution of symptoms may have different neurobiological basis in schizophrenia. While symptom unawareness may be a function of a more complex brain network, symptom misattribution may be mediated by specific brain regions.

Heterogeneity of structural brain changes in subtypes of schizophrenia revealed using magnetic resonance imaging pattern analysis

BACKGROUND

Schizophrenia is a multifaceted mental disorder characterized by cognitive, perceptual, and affective symptom dimensions. This heterogeneity at the phenomenological level may be subserved by complex and heterogeneous patterns of structural abnormalities. Thus, delineating such patterns may improve the insight into the variability of disease and facilitate future magnetic resonance imaging-based diagnosis.

METHODS

We aimed to identify structurally complex signatures that directly differentiate patients with predominantly negative (pNEG), positive (pPOS), and disorganized (pDIS) symptoms using Optimally-Discriminative Voxel-Based Analysis (ODVBA). ODVBA is a new analytical framework for group analysis, which showed to have superior sensitivity and specificity over conventional voxel-based morphometric approaches, thus facilitating the identification of subtle neuroanatomical signatures delineating different subgroups.

RESULTS

pPOS were characterized by pronounced gray matter (GM) volume reductions in the ventromedial prefrontal cortex (vmPFC), which herein is defined to include the orbitofrontal cortex, and in occipitotemporal GM and parts of the lingual gyrus. pNEG was found to have vmPFC reduction but to a lesser degree than pPOS and with a relative sparing of the more medial vmPFC regions, compared to pDIS; it also had significantly less cerebellar GM. pDIS showed relatively highest GM volume preservation among three subtypes.

CONCLUSIONS

Although a common prefronto-perisylvian GM reduction pattern was present at the whole-group level, marked morphometric differences emerged between the three subgroups, including reduced cerebellar GM in pNEG and reduced vmPFC and occipitotemporal GM in pPOS. Besides deepening our insight into the neurobiological underpinnings of clinical heterogeneity, these results also identify important imaging biomarkers that may aid patient stratification.

Prevalence and clinical correlates of obsessive-compulsive disorder in schizophrenia

Obsessive compulsive symptoms frequently occur in a substantial proportion of patients with schizophrenia. The term schizoobsessive has been proposed to delineate this subgroup of schizophrenia patients who present with obsessive-compulsive symptoms/disorder. However, whether this co-occurrence is more than just co-morbidity and represents a distinct subgroup remains controversial. A striking variation is noted across studies examining prevalence of obsessive-compulsive symptoms/disorder in schizophrenia patients and their impact on clinical profile of schizophrenia. Hence, in this study, we examined the prevalence of obsessive-compulsive symptoms/disorder in a large sample of consecutively hospitalized schizophrenia patients and compared the clinical and functional characteristics of schizophrenia patients with and without obsessive-compulsive symptoms/disorder. We evaluated 200 consecutive subjects with the DSM-IV diagnosis of schizophrenia using the Structured Clinical Interview for DSM-IV Axis I disorders, Positive and Negative Syndrome Scale, Yale-Brown Obsessive-Compulsive Scale, Brown Assessment of Beliefs Scale, Clinical Global Impression-Severity scale, Global Assessment of Functioning Scale, Family Interview for Genetic Studies and World Health Organization Quality of Life scale. The prevalence of obsessive-compulsive symptoms in patients with schizophrenia was 24% (n=48); 37 of them had obsessive-compulsive disorder (OCD) and 11 had obsessive-compulsive symptoms not amounting to a clinical diagnosis of OCD (OCS). Schizophrenia patients with OCS/OCD had an earlier age at onset of schizophrenia symptoms, lower positive symptoms score, higher co-morbidity with Axis II disorders, higher occurrence of OCD in family and better quality of life. Findings of the study indicate a higher prevalence of OCS/OCD in schizophrenia. Schizophrenia patients with and without OCS/OCD have comparable clinical profile with few exceptions. High rates of OCD in first degree relatives suggest possible genetic contributions and differences in neurobiology. Finally, evidence to consider schizoobsessive as a distinct diagnostic entity is inconclusive and warrants further studies.

Correlations between brain structure and symptom dimensions of psychosis in schizophrenia, schizoaffective, and psychotic bipolar I disorders

INTRODUCTION

Structural alterations may correlate with symptom severity in psychotic disorders, but the existing literature on this issue is heterogeneous. In addition, it is not known how cortical thickness and cortical surface area correlate with symptom dimensions of psychosis.

METHODS

Subjects included 455 individuals with schizophrenia, schizoaffective, or bipolar I disorders. Data were obtained as part of the Bipolar Schizophrenia Network for Intermediate Phenotypes study. Diagnosis was made through the Structured Clinical Interview for DSM-IV. Positive and negative symptom subscales were assessed using the Positive and Negative Syndrome Scale. Structural brain measurements were extracted from T1-weight structural MRIs using FreeSurfer v5.1 and were correlated with symptom subscales using partial correlations. Exploratory factor analysis was also used to identify factors among those regions correlating with symptom subscales.

RESULTS

The positive symptom subscale correlated inversely with gray matter volume (GMV) and cortical thickness in frontal and temporal regions, whereas the negative symptom subscale correlated inversely with right frontal cortical surface area. Among regions correlating with the positive subscale, factor analysis identified four factors, including a temporal cortical thickness factor and frontal GMV factor. Among regions correlating with the negative subscale, factor analysis identified a frontal GMV-cortical surface area factor. There was no significant diagnosis by structure interactions with symptom severity.

CONCLUSIONS

Structural measures correlate with positive and negative symptom severity in psychotic disorders. Cortical thickness demonstrated more associations with psychopathology than cortical surface area.

Shared intermediate phenotypes for schizophrenia and bipolar disorder: neuroanatomical features of subtypes distinguished by executive dysfunction

BACKGROUND

Shared genetic vulnerability for schizophrenia and bipolar disorder may be associated with common neuroanatomical features. In view of the evidence for working memory dysfunction as a candidate intermediate phenotype for both disorders, we explored neuroanatomical distinctions between subtypes defined according to working memory (n-back task) performance.

METHODS

We analyzed T1-weighted MRI scans for patients with schizophrenia-spectrum disorder, bipolar-I disorder (BD-I) and healthy controls. The VBM8 toolbox was used to assess differences in grey and white matter volume across traditional diagnostic groups (schizophrenia v. BD-I). Subsequently, groups were defined as "executively spared" (ES) based on the achievement of greater than 50% accuracy in the 2-back task performance (comparable to performance in the control group) or "executively deficit" (ED) based on the achievement of less than 50% accuracy.

RESULTS

Our study included 40 patients with schizophrenia-spectrum disorders, 30 patients with BD-I and 34 controls. Both the schizophrenia and BD-I groups showed grey matter volume reductions relative to the control group, but not relative to each other. The ED subtype (n = 32 [10 BD-I, 22 schizophrenia]) showed grey matter volume reductions in the bilateral superior and medial frontal gyri, right inferior opercular gyri and hippocampus relative to controls. The ES subtype (n = 38 [20 BD-I, 18 schizophrenia]) showed grey matter volume reductions in the right precuneus and left superior and medial orbital frontal gyri relative to controls. The ED subtype showed grey matter volume reduction in the right inferior frontal and precentral gyri relative to the ES subtype. There were no significant differences in white matter volume in any group comparisons.

LIMITATIONS

This analysis was limited by small sample sizes. Further, insufficient numbers were available to assess a control-deficit comparison group. We were unable to assess the effects of mood stabilizer dose on brain structure.

CONCLUSION

Neuroanatomical commonalities are evident among patients with schizophrenia-spectrum disorders and BD-I with working memory deficits. Reduced inferior frontal lobe volume may mediate cognitive deficits shared across the psychosis-mood spectrum.

Impaired insight into illness and cognitive insight in schizophrenia spectrum disorders: resting state functional connectivity

BACKGROUND

Impaired insight into illness (clinical insight) in schizophrenia has negative effects on treatment adherence and clinical outcomes. Schizophrenia is described as a disorder of disrupted brain connectivity. In line with this concept, resting state networks (RSNs) appear differentially affected in persons with schizophrenia. Therefore, impaired clinical, or the related construct of cognitive insight (which posits that impaired clinical insight is a function of metacognitive deficits), may reflect alterations in RSN functional connectivity (fc). Based on our previous research, which showed that impaired insight into illness was associated with increased left hemisphere volume relative to right, we hypothesized that impaired clinical insight would be associated with increased connectivity in the DMN with specific left hemisphere brain regions.

METHODS

Resting state MRI scans were acquired for participants with schizophrenia or schizoaffective disorder (n=20). Seed-to-voxel and ROI-to-ROI fc analyses were performed using the CONN-fMRI fc toolbox v13 for established RSNs. Clinical and cognitive insight were measured with the Schedule for the Assessment of Insight-Expanded Version and Beck Cognitive Insight Scale, respectively, and included as the regressors in fc analyses.

RESULTS

As hypothesized, impaired clinical insight was associated with increased connectivity in the default mode network (DMN) with the left angular gyrus, and also in the self-referential network (SRN) with the left insula. Cognitive insight was associated with increased connectivity in the dorsal attention network (DAN) with the right inferior frontal cortex (IFC) and left anterior cingulate cortex (ACC).

CONCLUSION

Increased connectivity in DMN and SRN with the left angular gyrus and insula, respectively, may represent neural correlates of impaired clinical insight in schizophrenia spectrum disorders, and is consistent with the literature attributing impaired insight to left hemisphere dominance. Increased connectivity in the DAN with the IFC and ACC in relation to cognitive insight may facilitate enhanced mental flexibility in this sample.

Neuropsychological and cerebral morphometric aspects of negative symptoms in schizophrenia: negative symptomatology is associated with specific mnestic deficits in schizophrenic patients

BACKGROUND

The prevalence of negative symptoms in schizophrenic patients seems to be an important indicator for treatment response and prognosis. Although negative symptoms have often been attributed to frontal lobe anomalies, neuropsychological and anatomical findings do not explicitly support this assumption. Since knowledge about the cerebral correlate of negative symptoms in schizophrenia might have a strong impact on therapeutic and psychopharmacological interventions, we aimed to answer this question by investigating the relationship between negative symptoms, neuropsychological functioning and cerebral volumes in schizophrenic patients.

METHODS

Twenty schizophrenic patients and 32 healthy controls were examined using a neuropsychological test battery for the assessment of temporal (mnestic) and frontal (executive) faculties. Volumetric measurements of temporal (hippocampus and amygdala) and frontal (orbitofrontal, dorsolateral prefrontal, and anterior cingulate area) brain areas were performed. Negative symptoms were assessed using the Scale for the Assessment of Negative Symptoms (SANS).

RESULTS

Schizophrenic patients performed worse than healthy controls in tests assessing verbal and visuospatial learning and memory functions and on the Stroop interference task. After dividing the schizophrenic group in patients with high and low SANS scores almost all of these deficits were restricted to the former group. There were no overall group differences regarding cerebral subarea volumes. Overall negative symptoms were significantly correlated with verbal memory functions but not with frontal lobe faculties.

CONCLUSIONS

Negative symptoms in schizophrenia could specifically associated with verbal memory deficits.

Illness-course modulates suicidality-related prefrontal gray matter reduction in women with bipolar disorder

OBJECTIVE

Explore interrelationships between suicide attempt history (Objective 1) or suicide attempt severity (Objective 2) with prefrontal cortex gray matter (PFCGM ) volume and illness-course in patients with bipolar disorder (BD).

METHOD

Ninety-three women with BD-I or -II diagnosis (51 with and 42 without suicide attempt history) underwent structural MRI and filled out questionnaires. Measured were GM volumes of 11 PFC regions, BD illness-course, and attempt history and severity. Effects were examined with repeated measures GLM or logit analyses.

RESULTS

Objective 1: Attempt history was associated with increased trait impulsivity and aggression, and higher prevalence of BD-I, past drug use disorder, and past psychiatric hospitalization. PFCGM volume was lower in patients with than without attempt history in those with past psychiatric hospitalization. PFCGM volume was higher in patients with than without attempt history in those without hospitalization. Higher trait aggression predicted attempt history. Objective 2: Increased frontal pole volume and younger age at first hospitalization predicted many suicide attempts.

CONCLUSION

Attempt history in patients with BD related to PFCGM volume reduction or increase. Volume modulation by psychiatric hospitalization could reflect effects of illness-course or care. Attempt severity was not related to volume reduction. Research on suicidality-brain relationships should include illness-course and attempt severity measures.

The effects of aging on insight into illness in schizophrenia: a review

OBJECTIVES

Impaired insight into illness is a prevalent feature of schizophrenia, which negatively influences treatment adherence and clinical outcomes. Little is known about the effects of aging on insight impairment. We aimed to review the available research literature on the effects of aging on insight into illness in schizophrenia, in relation to positive, negative, and cognitive symptoms. Ultimately, we propose a trajectory of insight in schizophrenia across the lifespan.

METHOD

A systematic Medline® literature search was conducted, searching for English language studies describing the relationship of insight into illness in schizophrenia with aging.

RESULTS

We identified 62 studies. Insight impairment is associated with illness severity, premorbid intellectual function (i.e. IQ), executive function, and memory. Insight impairment improves modestly during midlife, worsening again in late life. It tends to fluctuate with each episode of psychosis, likely in relation to worsening positive symptoms that improve with antipsychotic treatment. The relationship between insight impairment and cognitive dysfunction appears to attenuate with age, while the relationship with lower premorbid intellectual function is preserved. The association between impaired insight and negative symptoms is unclear.

CONCLUSIONS

The available literature suggests that the course of insight impairment follows a U-shaped curve, where insight impairment is severe during the first episode of psychosis, modestly improves over midlife, and declines again in late life. Future studies are required to investigate the trajectory of insight into illness and its core domains across the lifespan from prodromal phase to late life.

Extensive brain structural network abnormality in first-episode treatment-naive patients with schizophrenia: morphometrical and covariation study

BACKGROUND

Alterations in gray matter (GM) are commonly observed in schizophrenia. Accumulating studies suggest that the brain changes associated with schizophrenia are distributed rather than focal, involving interconnected networks of areas as opposed to single regions. In the current study we aimed to explore GM volume (GMV) changes in a relatively large sample of treatment-naive first-episode schizophrenia (FES) patients using optimized voxel-based morphometry (VBM) and covariation analysis.

METHOD

High-resolution T1-weighted images were obtained using 3.0-T magnetic resonance imaging (MRI) from 86 first-episode drug-naive patients with schizophrenia and 86 age- and gender-matched healthy volunteers. Symptom severity was evaluated using the Positive and Negative Syndrome Scale (PANSS). GMV was assessed using optimized VBM and in 16 regions of interest (ROIs), selected on the basis of a previous meta-analysis. The relationships between GMVs in the ROIs were examined using an analysis of covariance (ANCOVA).

RESULTS

The VBM analysis revealed that first-episode patients showed reduced GMV in the hippocampus bilaterally. The ROI analysis identified reductions in GMV in the left inferior frontal gyrus, bilateral hippocampus and right thalamus. The ANCOVA revealed different patterns of regional GMV correlations in patients and controls, including of inter- and intra-insula, inter-amygdala and insula-postcentral gyrus connections.

CONCLUSIONS

Schizophrenia involves regional reductions in GMV and changes in GMV covariance in the insula, amygdala and postcentral gyrus. These findings were evident at the onset of the disorder, before treatment, and therefore cannot be attributable to the effects of chronic illness progression or medication.

Selective effect of neurocognition on different theory of mind domains in first-episode psychosis

The aim of this study was to investigate the influence of neurocognition on affective and cognitive theory of mind (ToM) tasks in early phases of psychosis. In a cross-sectional study of 60 first-episode schizophrenia/schizoaffective disorder patients, the implication of neurocognition in first- and second-order ToM stories, Hinting Task, and Reading the Mind in the Eyes Test (RMET) was analyzed. Regression models were used, controlling for clinical symptoms and antipsychotic dose. Spatial span backward (odds ratio [OR], 0.34; p = 0.01) and intrusions in the Rey Auditory Verbal Learning Test (OR, 4.86; p = 0.04) were the best factors to predict second-order ToM failure. Trail Making Test B (B = 0.01; p = 0.04) and negative symptoms (B = 0.09; p = 0.01) predicted Hinting task performance while Block design (B = 0.1; p = 0.04) was related to RMET outcome. Executive functions and clinical symptoms were related to ToM performance in first-episode schizophrenia patients, although different patterns of relationship were observed in each ToM task.

Neural correlates of insight in dreaming and psychosis

The idea that dreaming can serve as a model for psychosis has a long and honourable tradition, however it is notoriously speculative. Here we demonstrate that recent research on the phenomenon of lucid dreaming sheds new light on the debate. Lucid dreaming is a rare state of sleep in which the dreamer gains insight into his state of mind during dreaming. Recent electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) data for the first time allow very specific hypotheses about the dream-psychosis relationship: if dreaming is a reasonable model for psychosis, then insight into the dreaming state and insight into the psychotic state should share similar neural correlates. This indeed seems to be the case: cortical areas activated during lucid dreaming show striking overlap with brain regions that are impaired in psychotic patients who lack insight into their pathological state. This parallel allows for new therapeutic approaches and ways to test antipsychotic medication.

Insight facilitation with add-on tDCS in schizophrenia

Impaired insight in schizophrenia patients has been linked with prefrontal deficits. In this open-label study, we examined for potential insight facilitation effects of add-on tDCS (with anodal stimulation of left DLPFC and cathodal stimulation over left temporo-parietal junction) in schizophrenia patients (N=21) with persistent auditory hallucinations despite adequate antipsychotic treatment. Following tDCS, there was a significant improvement in insight with concurrent significant reduction in auditory hallucination severity. Improvement in insight correlated significantly with improvement in severity of auditory hallucinations. These findings suggest improvement of insight with add-on tDCS in schizophrenia with persistent auditory hallucinations.

Negative symptoms of schizophrenia: clinical characteristics, pathophysiological substrates, experimental models and prospects for improved treatment

Schizophrenia is a complex and multifactorial disorder generally diagnosed in young adults at the time of the first psychotic episode of delusions and hallucinations. These positive symptoms can be controlled in most patients by currently-available antipsychotics. Conversely, they are poorly effective against concomitant neurocognitive dysfunction, deficits in social cognition and negative symptoms (NS), which strongly contribute to poor functional outcome. The precise notion of NS has evolved over the past century, with recent studies - underpinned by novel rating methods - suggesting two major sub-domains: "decreased emotional expression", incorporating blunted affect and poverty of speech, and "avolition", which embraces amotivation, asociality and "anhedonia" (inability to anticipate pleasure). Recent studies implicate a dysfunction of frontocortico-temporal networks in the aetiology of NS, together with a disruption of cortico-striatal circuits, though other structures are also involved, like the insular and parietal cortices, amygdala and thalamus. At the cellular level, a disruption of GABAergic-glutamatergic balance, dopaminergic signalling and, possibly, oxytocinergic and cannibinoidergic transmission may be involved. Several agents are currently under clinical investigation for the potentially improved control of NS, including oxytocin itself, N-Methyl-d-Aspartate receptor modulators and minocycline. Further, magnetic-electrical "stimulation" strategies to recruit cortical circuits and "cognitive-behavioural-psychosocial" therapies likewise hold promise. To acquire novel insights into the causes and treatment of NS, experimental study is crucial, and opportunities are emerging for improved genetic, pharmacological and developmental modelling, together with more refined readouts related to deficits in reward, sociality and "expression". The present article comprises an integrative overview of the above issues as a platform for this Special Issue of European Neuropsychopharmacology in which five clinical and five preclinical articles treat individual themes in greater detail. This Volume provides, then, a framework for progress in the understanding - and ultimately control - of the debilitating NS of schizophrenia.

Preservation and compensation: the functional neuroanatomy of insight and working memory in schizophrenia

BACKGROUND

Poor insight in schizophrenia has been theorised to reflect a cognitive deficit that is secondary to brain abnormalities, localized in the brain regions that are implicated in higher order cognitive functions, including working memory (WM). This study investigated WM-related neural substrates of preserved and poor insight in schizophrenia.

METHOD

Forty stable schizophrenia outpatients, 20 with preserved and 20 with poor insight (usable data obtained from 18 preserved and 14 poor insight patients), and 20 healthy participants underwent functional magnetic resonance imaging (fMRI) during a parametric 'n-back' task. The three groups were preselected to match on age, education and predicted IQ, and the two patient groups to have distinct insight levels. Performance and fMRI data were analysed to determine how groups of patients with preserved and poor insight differed from each other, and from healthy participants.

RESULTS

Poor insight patients showed lower performance accuracy, relative to healthy participants (p=0.01) and preserved insight patients (p=0.08); the two patient groups were comparable on symptoms and medication. Preserved insight patients, relative to poor insight patients, showed greater activity most consistently in the precuneus and cerebellum (both bilateral) during WM; they also showed greater activity than healthy participants in the inferior-superior frontal gyrus and cerebellum (bilateral). Group differences in brain activity did not co-vary significantly with performance accuracy.

CONCLUSIONS

The precuneus and cerebellum function contribute to preserved insight in schizophrenia. Preserved insight as well as normal-range WM capacity in schizophrenia sub-groups may be achieved via compensatory neural activity in the frontal cortex and cerebellum.

Brain structural signatures of negative symptoms in depression and schizophrenia

Negative symptoms occur in several major mental health disorders with undetermined mechanisms and unsatisfactory treatments; identification of their neural correlates might unveil the underlying pathophysiological basis and pinpoint the therapeutic targets. In this study, participants with major depressive disorder (n = 24), schizophrenia (n = 22), and healthy controls (n = 20) were assessed with 10 frequently used negative symptom scales followed by principal component analysis (PCA) of the scores. A linear model with the prominent components identified by PCA was then regressed on gray and white-matter volumes estimated from T1-weighted magnetic resonance imaging. In depressed patients, negative symptoms such as blunted affect, alogia, withdrawal, and cognitive impairment, assessed mostly via clinician-rated scales were inversely associated with gray matter volume in the bilateral cerebellum. In patients with schizophrenia, anhedonia, and avolition evaluated via self-rated scales inversely related to white-matter volume in the left anterior limb of internal capsule/anterior thalamic radiation and positively in the left superior longitudinal fasiculus. The pathophysiological mechanisms underlying negative symptoms might differ between depression and schizophrenia. These results also point to future negative symptom scale development primarily focused on detecting and monitoring the corresponding changes to brain structure or function.

Neuroanatomical phenotypes in a mouse model of the 22q11.2 microdeletion

Recurrent deletions at the 22q11.2 locus have been established as a strong genetic risk factor for the development of schizophrenia and cognitive dysfunction. Individuals with 22q11.2 deletions have a range of well-defined volumetric abnormalities in a number of critical brain structures. A mouse model of the 22q11.2 deletion (Df(16)A(+/-)) has previously been utilized to characterize disease-associated abnormalities on synaptic, cellular, neurocircuitry, and behavioral levels. We performed a high-resolution MRI analysis of mutant mice compared with wild-type littermates. Our analysis revealed a striking similarity in the specific volumetric changes of Df(16)A(+/-) mice compared with human 22q11.2 deletion carriers, including in cortico-cerebellar, cortico-striatal and cortico-limbic circuits. In addition, higher resolution magnetic resonance imaging compared with neuroimaging in human subjects allowed the detection of previously unknown subtle local differences. The cerebellar findings in Df(16)A(+/-) mice are particularly instructive as they are localized to specific areas within both the deep cerebellar nuclei and the cerebellar cortex. Our study indicates that the Df(16)A(+/-)mouse model recapitulates most of the hallmark neuroanatomical changes observed in 22q11.2 deletion carriers. Our findings will help guide the design and interpretation of additional complementary studies and thereby advance our understanding of the abnormal brain development underlying the emergence of 22q11.2 deletion-associated psychiatric and cognitive symptoms.

Anatomical substrates of cognitive and clinical dimensions in first episode schizophrenia

OBJECTIVE

To explore gray (GM) and white matter (WM) abnormalities and the relationships with neuropsychopathology in first-episode schizophrenia (FES).

METHOD

Nineteen patients with first episode of non-affective psychosis and 18 controls underwent a magnetic resonance voxel-based morphometry. Additionally, WM fractional anisotropy (FA) was calculated. For correlative analysis, symptoms and neuropsychological performances were scored by PANSS and by a comprehensive neuropsychological assessment respectively.

RESULTS

Patients showed significantly decreased volume of left temporal lobe and disarray of all major WM tracts. Disorganized PANSS factor was inversely related to left cerebellar GM volume (corrected P = 0.03) and to WM FA of the left cerebellum, inferior fronto-occipital fasciculi (IFOF), and inferior longitudinal fasciculi (corrected P < 0.05). PANSS negative factor was inversely related to FA in the IFOF and superior longitudinal fasciculi (corrected P < 0.05). Impairment in facial emotion identification showed associations with temporo-occipital GM volume decrease (corrected P = 0.003) and WM disarray of superior and middle temporal gyri, anterior thalamic radiation, and superior longitudinal fasciculi (corrected P < 0.05). Speed of processing and visual memory correlated with WM abnormalities in fronto-temporal tracts.

CONCLUSION

These results confirm how the structural development of key brain regions is related to neuropsychopathological dysfunction in FES, consistently with a neurodevelopmentally derived misconnection syndrome.

Frontotemporoparietal asymmetry and lack of illness awareness in schizophrenia

INTRODUCTION

Lack of illness awareness or anosognosia occurs in both schizophrenia and right hemisphere lesions due to stroke, dementia, and traumatic brain injury. In the latter conditions, anosognosia is thought to arise from unilateral hemispheric dysfunction or interhemispheric disequilibrium, which provides an anatomical model for exploring illness unawareness in other neuropsychiatric disorders, such as schizophrenia.

METHODS

Both voxel-based morphometry using Diffeomorphic Anatomical Registration through Exponentiated Lie Algebra (DARTEL) and a deformation-based morphology analysis of hemispheric asymmetry were performed on 52 treated schizophrenia subjects, exploring the relationship between illness awareness and gray matter volume. Analyses included age, gender, and total intracranial volume as covariates.

RESULTS

Hemispheric asymmetry analyses revealed illness unawareness was significantly associated with right < left hemisphere volumes in the anteroinferior temporal lobe (t = 4.83, P = 0.051) using DARTEL, and the dorsolateral prefrontal cortex (t = 5.80, P = 0.003) and parietal lobe (t = 4.3, P = 0.050) using the deformation-based approach. Trend level associations were identified in the right medial prefrontal cortex (t = 4.49, P = 0.127) using DARTEL. Lack of illness awareness was also strongly associated with reduced total white matter volume (r = 0.401, P < 0.01) and illness severity (r = 0.559, P < 0.01).

CONCLUSION

These results suggest a relationship between anosognosia and hemispheric asymmetry in schizophrenia, supporting previous volume-based MRI studies in schizophrenia that found a relationship between illness unawareness and reduced right hemisphere gray matter volume. Functional imaging studies are required to examine the neural mechanisms contributing to these structural observations.

Schizophrenia and frontotemporal dementia: shared causation?

The relationship between specific genes and particular diseases in neuropsychiatry is unclear, and newer studies focus on shared domains of neurobiological and cognitive pathology across different disorders. This paper reviews the evidence for an association between schizophrenia and frontotemporal dementia, including symptom similarity, familial co-morbidity, and neuroanatomical changes. Genetic as well as epigenetic findings from both schizophrenia and frontotemporal dementia are also discussed. As a result, we introduce the hypothesis of a shared susceptibility for certain subgroups of schizophrenia and frontotemporal dementia. This common causation may involve the same gene(s) at different stages of life: early in schizophrenia and late in frontotemporal dementia. Additionally, we provide a rationale for future research that should emphasize both genetic and cognitive parallels between certain forms of schizophrenia and frontotemporal dementia in a synergistic, coordinated way, placing both in the context of aberrant lateralization patterns.

Structural imaging techniques in schizophrenia

OBJECTIVE

The aim of this overview study is to translate the technical terminology regarding structural Magnetic Resonance Imaging (sMRI) post-processing analysis into a clinical clear description.

METHOD

We resumed and explained the most popular post-processing methods for structural MRI (sMRI) data applied in psychiatry and their main contributions to the comprehension of the biological basis of schizophrenia.

RESULTS

The region-of-interest (ROI) technique allows to investigate specific brain region size by manual tracing; it is anatomically precise and requires a priori hypothesis, but also it is time-consuming and operator-dependent. The voxel-based morphometry (VBM) detects gray matter density across the whole brain by comparing voxel to voxel; it is operator-independent, does not require a priori hypothesis, and is relatively fast; however, it is limited by multiple comparisons and poor anatomical definition. Finally, computational neuroanatomical analyses have recently been applied to automatically discriminate subjects with schizophrenia from healthy subjects on the basis of MRI images.

CONCLUSION

Structural MRI represents a useful tool in understanding the biological underpinnings of schizophrenia and in planning focused interventions, thus assisting clinicians especially in the early phases of the illness.

Failures of metacognition and lack of insight in neuropsychiatric disorders

Lack of insight or unawareness of illness are the hallmarks of many psychiatric disorders, especially schizophrenia (SCZ) and other psychoses and could be conceived of as a failure in metacognition. Research in this area in the mental health field h as burgeoned with the development and widespread use of standard assessment instruments and the mapping out of the clinical and neuropsychological correlates of insight and its loss. There has been a growing appreciation of the multi-faceted nature of the concept and of the different 'objects' of insight, such as the general awareness that one is ill, to more specific metacognitive awareness of individual symptoms, impairments and performance. This in turn has led to the notion that insight may show modularity and may fractionate across different domains and disorders, supported by work that directly compares metacognition of memory deficits and illness awareness in patients with SCZ, Alzheimer's disease and brain injury. The focus of this paper will be on the varieties of metacognitive failure in psychiatry, particularly the psychoses. We explore cognitive models based on self-reflectiveness and their possible social and neurological bases, including data from structural and functional MRI. The medial frontal cortex appears to play an important role in self-appraisal in health and disease.

Magnetic resonance imaging correlates of first-episode psychosis in young adult male patients: combined analysis of grey and white matter

BACKGROUND

Several patterns of grey and white matter changes have been separately described in young adults with first-episode psychosis. Concomitant investigation of grey and white matter densities in patients with first-episode psychosis without other psychiatric comorbidities that include all relevant imaging markers could provide clues to the neurodevelopmental hypothesis in schizophrenia.

METHODS

We recruited patients with first-episode psychosis diagnosed according to the DSM-IV-TR and matched controls. All participants underwent magnetic resonance imaging (MRI). Voxel-based morphometry (VBM) analysis and mean diffusivity voxel-based analysis (VBA) were used for grey matter data. Fractional anisotropy and axial, radial and mean diffusivity were analyzed using tract-based spatial statistics (TBSS) for white matter data.

RESULTS

We included 15 patients and 16 controls. The mean diffusivity VBA showed significantly greater mean diffusivity in the first-episode psychosis than in the control group in the lingual gyrus bilaterally, the occipital fusiform gyrus bilaterally, the right lateral occipital gyrus and the right inferior temporal gyrus. Moreover, the TBSS analysis revealed a lower fractional anisotropy in the first-episode psychosis than in the control group in the genu of the corpus callosum, minor forceps, corticospinal tract, right superior longitudinal fasciculus, left middle cerebellar peduncle, left inferior longitudinal fasciculus and the posterior part of the fronto-occipital fasciculus. This analysis also revealed greater radial diffusivity in the first-episode psychosis than in the control group in the right corticospinal tract, right superior longitudinal fasciculus and left middle cerebellar peduncle.

LIMITATIONS

The modest sample size and the absence of women in our series could limit the impact of our results.

CONCLUSION

Our results highlight the structural vulnerability of grey matter in posterior areas of the brain among young adult male patients with first-episode psychosis. Moreover, the concomitant greater radial diffusivity within several regions already revealed by the fractional anisotropy analysis supports the idea of a late myelination in patients with first-episode psychosis.

Self-evaluation in schizophrenia: an fMRI study with implications for the understanding of insight

BACKGROUND

Lack of insight is a core feature of schizophrenia and is associated with structural brain abnormalities. The functional neuroanatomy of insight has only recently been investigated. When people evaluate their personality traits compared to those of another, activation is seen in central midline structures (CMS) of the brain. This study set out to compare cerebral activation in schizophrenia patients versus controls during a self-evaluation task which included positive and negative traits as well as mental and physical illness terms.

METHODS

Eleven schizophrenia patients and 8 healthy controls, matched for age were studied. Insight was assessed using the Schedule for the Assessment of Insight-expanded version (SAI-E). FMRI data were obtained with a 1.5 Tesla GE system and interactions between participant group, self versus other, significant at the cluster level, were recorded.

RESULTS

Significant hypoactivation in the medial superior frontal gyrus (dorsomedial prefrontal cortex) was observed in patients vs. controls during self-evaluation of all traits combined. A second cluster of hypoactivation in the posterior cingulate was also detected. When the response to individual traits was explored, underactivation in other frontal regions plus right inferior parietal lobule emerged and this tended to correlate, albeit weakly with lower insight scores. Further, there were areas of hyperactivation relative to controls in anterior cingulate, frontal and parietal regions (especially precuneus) which showed moderate inverse correlations with insight scores.

CONCLUSIONS

We have demonstrated that the CMS, identified as a key system underpinning self-evaluation, is dysfunctional in patients with schizophrenia, particularly dorso-medial PFC. This may have implications for lack of insight in schizophrenia. Hypofunction within the dorsomedial prefrontal region seems to be particularly important although other posterior and lateral cortical regions play a part and may modulate self-evaluative responses depending on the type of trait under consideration.

Structural brain changes in First Episode Schizophrenia compared with Fronto-Temporal Lobar Degeneration: a meta-analysis

BACKGROUND

The authors sought to compare gray matter changes in First Episode Schizophrenia (FES) compared with Fronto-Temporal Lobar Degeneration (FTLD) using meta-analytic methods applied to neuro-imaging studies.

METHODS

A systematic search was conducted for published, structural voxel-based morphometric MRI studies in patients with FES or FTLD. Data were combined using anatomical likelihood estimation (ALE) to determine the extent of gray matter decreases and analysed to ascertain the degree of overlap in the spatial distribution of brain changes in both diseases.

RESULTS

Data were extracted from 18 FES studies (including a total of 555 patients and 621 comparison subjects) and 20 studies of FTLD or related disorders (including a total of 311 patients and 431 comparison subjects). The similarity in spatial overlap of brain changes in the two disorders was significant (p = 0.001). Gray matter deficits common to both disorders included bilateral caudate, left insula and bilateral uncus regions.

CONCLUSIONS

There is a significant overlap in the distribution of structural brain changes in First Episode Schizophrenia and Fronto-Temporal Lobar Degeneration. This may reflect overlapping aetiologies, or a common vulnerability of these regions to the distinct aetio-pathological processes in the two disorders.

The structural neural substrates of persistent negative symptoms in first-episode of non-affective psychosis: a voxel-based morphometry study

OBJECTIVES

An important subset of patients with schizophrenia present clinically significant persistent negative symptoms (PNS). Identifying the neural substrates of PNS could help improve our understanding and treatment of these symptoms.

METHODS

This study included 64 non-affective first-episode of psychosis (FEP) patients and 60 healthy controls; 16 patients displayed PNS (i.e., at least one primary negative symptom at moderate or worse severity sustained for at least six consecutive months). Using voxel-based morphometry (VBM), we explored for gray matter differences between PNS and non-PNS patients; patient groups were also compared to controls. All comparisons were performed at p < 0.05, corrected for multiple comparisons.

RESULTS

PNS patients had smaller gray matter in the right frontal medial-orbital gyrus (extending into the inferior frontal gyrus) and right parahippocampal gyrus (extending into the fusiform gyrus) compared to non-PNS patients. Compared to controls, PNS patients had smaller gray matter in the right parahippocampal gyrus (extending into the fusiform gyrus and superior temporal gyrus); non-PNS patients showed no significant differences to controls.

CONCLUSION

Neural substrates of PNS are evident in FEP patients. A better understanding of the neural etiology of PNS may encourage the search for new medications and/or alternative treatments to better help those affected.

Putative structural neuroimaging endophenotypes in schizophrenia: a comprehensive review of the current evidence

The genetic contribution to schizophrenia etiopathogenesis is underscored by the fact that the best predictor of developing schizophrenia is having an affected first-degree relative, which increases lifetime risk by tenfold, as well as the observation that when both parents are affected, the risk of schizophrenia increases to approximately 50%, compared with 1% in the general population. The search to elucidate the complex genetic architecture of schizophrenia has employed various approaches, including twin and family studies to examine co-aggregation of brain abnormalities, studies on genetic linkage and studies using genome-wide association to identify genetic variations associated with schizophrenia. ‘Endophenotypes’, or ‘intermediate phenotypes’, are potentially narrower constructs of genetic risk. Hypothetically, they are intermediate in the pathway between genetic variation and clinical phenotypes and can supposedly be implemented to assist in the identification of genetic diathesis for schizophrenia and, possibly, in redefining clinical phenomenology.