Early-onset schizophrenia is associated with immune-related rare variants in a Chinese sample

Background

Rare variants are likely to contribute to schizophrenia (SCZ), given the large discrepancy between the heritability estimated from twin and GWAS studies. Furthermore, the nature of the rare-variant contribution to SCZ may vary with the "age-at-onset" (AAO), since early-onset has been suggested as being indicative of neurodevelopment deviance.

Objective

To examine the association of rare deleterious coding variants in early- and adult-onset SCZ in a Chinese sample.

Method

Exome sequencing was performed on DNA from 197 patients with SCZ spectrum disorder and 82 healthy controls (HC) of Chinese ancestry recruited in Hong Kong. We also gathered AAO information in the majority of SCZ samples. Patients were classified into early-onset (EOS, AAO<18) and adult-onset (AOS, AAO>18). We collapsed the rare variants to improve statistical power and examined the overall association of rare variants in SCZ versus HC, EOS versus HC, and AOS versus HC at the gene and gene-set levels by Sequence Kernel Association Test. The quantitative rare-variant association test of AAO was also conducted. We focused on variants which were predicted to have a medium or high impact on the protein-encoding process as defined by Ensembl. We applied a 100000-time permutation test to obtain empirical p-values, with significance threshold set at p < 1e -3 to control family-wise error rates. Moreover, we compared the burden of targeted rare variants in significant risk genes and gene sets in cases and controls.

Results

Based on several binary-trait association tests (i.e., SCZ vs HC, EOS vs HC and AOS vs HC), we identified 7 candidate risk genes and 20 gene ontology biological processes (GOBP) terms, which exhibited higher burdens in SCZ than in controls. Based on quantitative rare-variant association tests, we found that alterations in 5 candidate risk genes and 7 GOBP pathways were significantly correlated with AAO. Based on biological and functional profiles of the candidate risk genes and gene sets, our findings suggested that, in addition to the involvement of perturbations in neural systems in SCZ in general, altered immune responses may be specifically implicated in EOS.

Conclusion

Disrupted immune responses may exacerbate abnormal perturbations during neurodevelopment and trigger the early onset of SCZ. We provided evidence of rare variants increasing SCZ risk in the Chinese population.

Anterior cingulate glutamate levels associate with functional activation and connectivity during sensory integration in schizophrenia: a multimodal 1H-MRS and fMRI study

BACKGROUND

Glutamatergic dysfunction has been implicated in sensory integration deficits in schizophrenia, yet how glutamatergic function contributes to behavioural impairments and neural activities of sensory integration remains unknown.

METHODS

Fifty schizophrenia patients and 43 healthy controls completed behavioural assessments for sensory integration and underwent magnetic resonance spectroscopy (MRS) for measuring the anterior cingulate cortex (ACC) glutamate levels. The correlation between glutamate levels and behavioural sensory integration deficits was examined in each group. A subsample of 20 pairs of patients and controls further completed an audiovisual sensory integration functional magnetic resonance imaging (fMRI) task. Blood Oxygenation Level Dependent (BOLD) activation and task-dependent functional connectivity (FC) were assessed based on fMRI data. Full factorial analyses were performed to examine the Group-by-Glutamate Level interaction effects on fMRI measurements (group differences in correlation between glutamate levels and fMRI measurements) and the correlation between glutamate levels and fMRI measurements within each group.

RESULTS

We found that schizophrenia patients exhibited impaired sensory integration which was positively correlated with ACC glutamate levels. Multimodal analyses showed significantly Group-by-Glutamate Level interaction effects on BOLD activation as well as task-dependent FC in a 'cortico-subcortical-cortical' network (including medial frontal gyrus, precuneus, ACC, middle cingulate gyrus, thalamus and caudate) with positive correlations in patients and negative in controls.

CONCLUSIONS

Our findings indicate that ACC glutamate influences neural activities in a large-scale network during sensory integration, but the effects have opposite directionality between schizophrenia patients and healthy people. This implicates the crucial role of glutamatergic system in sensory integration processing in schizophrenia.

Emotion-behaviour decoupling and experiential pleasure deficits predict negative symptoms and functional outcome in first-episode schizophrenia patients

BACKGROUND

Emotion-behaviour decoupling refers to the failure to translate emotion into motivated behaviour, and is a putative marker for schizophrenia. The heterogeneity of experiential pleasure and emotion expressivity deficits has been reported in schizophrenia patients. These three constructs are believed to contribute to negative symptoms, but very few studies have examined their predictive ability for clinical and functional outcome of schizophrenia. This study aimed to clarify whether these three constructs influence clinical and functional outcome of schizophrenia.

METHOD

At baseline, 127 first-episode schizophrenia patients completed a behavioural paradigm for emotion-behaviour decoupling, and self-report scales for experiential pleasure and emotion expressivity deficits. Cluster-analysis was applied to characterize schizophrenia subgroups based on these three constructs. At end-point (mean follow-up = 5.37 years, SD = 1.03 years), 85 schizophrenia patients were reassessed using the Clinical Assessment Interview for Negative Symptoms (CAINS) and a clinician-rated social functioning scale.

RESULTS

Cluster 1 (n = 74) did not show emotion-behaviour decoupling, and had intact experiential pleasure and emotion expressivity. Cluster 2 (n = 29) showed emotion-behaviour decoupling and experiential pleasure deficits. Cluster 3 (n = 24) showed emotion expressivity deficits. At endpoint, the three clusters differed significantly in CAINS MAP factor (p = 0.016) and social functioning (p = 0.019), but not CAINS EXP factor. Specifically, Cluster 2 (n = 18) showed more severe negative symptoms of CAINS MAP factor (p = 0.046) and poorer social functioning (p = 0.022) than Cluster 1 (n = 49). Cluster 3 (n = 18) did not differ from Cluster 1 and Cluster 2 in negative symptoms and social functioning.

DISCUSSION

Emotion-behaviour decoupling and experiential pleasure deficits predicted clinical and functional outcome of schizophrenia.

Revisiting the latent structure of negative symptoms in schizophrenia: Evidence from two second-generation clinical assessments

BACKGROUND

Negative symptoms are core symptom of schizophrenia, and many previous research studied the latent structure of negative symptoms based on a single measurement scale. Applying two second-generation negative symptom scales to the same sample can address measurement-invariance of latent structure.

METHODS

Three-hundred-and-five schizophrenia patients were assessed using the CAINS and the BNSS. Confirmatory Factor Analysis (CFA) tested four competing factor-models: (1) a 1-factor model; (2) a 2-factor model comprising the motivation and pleasure (MAP) domain and the diminished expression (EXP) domain; (3) a 5-factor model comprising anhedonia, avolition, asociality, blunted affect and alogia; (4) a hierarchical model comprising the "first-order" 5-domain factors and the "second-order" MAP &amp; EXP factors.

RESULTS

The CFA results for the data of the CAINS showed that the 2-factor model had the best data fit over the other competing models. The CFA using the BNSS data in the same sample also supported the superiority of the 2-factor model. Lastly, after combining the items of the BNSS and CAINS together in the same sample for CFA, the 2-factor model prevailed over the other competing models.

CONCLUSIONS

The 2-factor model appears to be measurement-invariant latent structure of negative symptoms. The novel method of combining the items of the CAINS and BNSS might have circumvented the possible imperfect construct of a single scale. Our findings support the MAP and EXP factors as the latent structure for negative symptoms.

The impact of childhood trauma on thalamic functional connectivity in patients with obsessive-compulsive disorder

BACKGROUND

Childhood trauma is a vulnerability factor for the development of obsessive-compulsive disorder (OCD). Empirical findings suggest that trauma-related alterations in brain networks, especially in thalamus-related regions, have been observed in OCD patients. However, the relationship between childhood trauma and thalamic connectivity in patients with OCD remains unclear. The present study aimed to examine the impact of childhood trauma on thalamic functional connectivity in OCD patients.

METHODS

Magnetic resonance imaging resting-state scans were acquired in 79 patients with OCD, including 22 patients with a high level of childhood trauma (OCD_HCT), 57 patients with a low level of childhood trauma (OCD_LCT) and 47 healthy controls. Seven thalamic subdivisions were chosen as regions of interest (ROIs) to examine the group difference in thalamic ROIs and whole-brain resting-state functional connectivity (rsFC).

RESULTS

We found significantly decreased caudate-thalamic rsFC in OCD patients as a whole group and also in OCD_LCT patients, compared with healthy controls. However, OCD_HCT patients exhibited increased thalamic rsFC with the prefrontal cortex when compared with both OCD_LCT patients and healthy controls.

CONCLUSIONS

Taken together, OCD patients with high and low levels of childhood trauma exhibit different pathological alterations in thalamic rsFC, suggesting that childhood trauma may be a predisposing factor for some OCD patients.

Structural network alterations and their association with neurological soft signs in schizophrenia: Evidence from clinical patients and unaffected siblings

BACKGROUND

Grey matter abnormalities and neurological soft signs (NSS) have been found in schizophrenia patients and their unaffected relatives. Evidence suggested that NSS are associated with grey matter morphometrical alterations in multiple regions in schizophrenia. However, the association between NSS and structural abnormalities at network level remains largely unexplored, especially in the schizophrenia and unaffected siblings.

METHOD

We used source-based morphometry (SBM) to examine the association of structural brain network characteristics with NSS in 62 schizophrenia patients, 25 unaffected siblings, and 60 healthy controls.

RESULTS

Two components, namely the IC-5 (superior temporal gyrus, inferior frontal gyrus and insula network) and the IC-10 (parahippocampal gyrus, fusiform, thalamus and insula network) showed significant grey matter reductions in schizophrenia patients compared to healthy controls and unaffected siblings. Further association analysis demonstrated separate NSS-related grey matter covarying patterns in schizophrenia, unaffected siblings and healthy controls. Specifically, NSS were negatively associated with IC-1 (hippocampus, caudate and thalamus network) and IC-5 in schizophrenia, but with IC-3 (caudate, superior and middle frontal cortices network) in unaffected siblings and with IC-5 in healthy controls.

CONCLUSION

Our results confirmed the key cortical and subcortical network abnormalities and NSS-related grey matter covarying patterns in the schizophrenia and unaffected siblings. Our findings suggest that brain regions implicating genetic liability to schizophrenia are partly separated from brain regions implicating neural abnormalities.

Altered empathy-related resting-state functional connectivity in patients with bipolar disorder

Empathy is the ability to generate emotional responses (i.e., cognitive empathy) and to make cognitive inferences (i.e., affective empathy) to other people's emotions. Empirical evidence suggests that patients with bipolar disorder (BD) exhibit impairment in cognitive empathy, but findings on affective empathy are inconsistent. Few studies have examined the neural mechanisms of cognitive and affective empathy in patients with BD. In this study, we examined the empathy-related resting-state functional connectivity (rsFC) in BD patients. Thirty-seven patients with BD and 42 healthy controls completed the self-report Questionnaires of Cognitive and Affective Empathy (QCAE), the Yoni behavioural task, and resting-sate fMRI brain scans. Group comparison of empathic ability was conducted. The interactions between group and empathic ability on seed-based whole brain rsFC were examined. BD patients scored lower on the Online Simulation subscale of the QCAE and showed positive correlations between cognitive empathy and the rsFC of the dorsal Medial Prefrontal Cortex (dmPFC) with the lingual gyrus. The correlations between cognitive empathy and the rsFC of the temporal-parietal junction (TPJ) with the fusiform gyrus, the cerebellum and the parahippocampus were weaker in BD patients than that in healthy controls. These findings highlight the underlying neural mechanisms of empathy impairments in BD patients.

Shared and distinct reward neural mechanisms among patients with schizophrenia, major depressive disorder, and bipolar disorder: an effort-based functional imaging study

Unwillingness to exert effort for rewards has been found in patients with schizophrenia (SCZ), major depressive disorder (MDD), and bipolar disorder (BD), but the underlying shared and distinct reward neural mechanisms remain unclear. This study aimed to compare the neural correlates of such impairments across different diagnoses. The neural responses in an effort-expenditure for reward task (EEfRT) were assessed in 20 SCZ patients, 23 MDD patients, 17 BD patients, and 30 healthy controls (HC). The results found shared activation in the cingulate gyrus, the medial frontal gyrus, and the middle frontal gyrus during the EEfRT administration. Compared to HC, SCZ patients exhibited stronger variations of functional connectivity between the right caudate and the left amygdala, the left hippocampus and the left putamen, with increase in reward magnitude. In MDD patients, an enhanced activation compared to HC in the right superior temporal gyrus was found with the increase of reward magnitude. The variations of functional connectivity between the caudate and the right cingulate gyrus, the left postcentral gyrus and the left inferior parietal lobule with increase in reward magnitude were weaker than that found in HC. In BD patients, the degree of activation in the left precuneus was increased, but that in the left dorsolateral prefrontal cortex was decreased with increase in reward probability compared to HC. These findings demonstrate both shared and distinct reward neural mechanisms associated with EEfRT in patients with SCZ, MDD, and BD, implicating potential intervention targets to alleviate amotivation in these clinical disorders.

Negative belief-updating bias for positive daily life events in individuals with schizophrenia and social anhedonia

INTRODUCTION

Low-pleasure beliefs are found in both patients with schizophrenia (SZ) and individuals with high social anhedonia (SocAnh), and are associated with anhedonia. However, little is known about the development and maintenance of these low-pleasure beliefs in the clinical and subclinical populations. We investigated whether patients with SZ and individuals with high SocAnh have deficits in updating their beliefs, which may contribute to the understanding of the formation and maintenance of low-pleasure beliefs.

METHODS

The Modified Belief Updating Task was administered to assess belief-updating patterns in a clinical sample (36 SZ patients and 30 matched controls) and a subclinical sample (27 individuals with high SocAnh and 30 matched controls).

RESULTS

We found that compared with controls, SZ patients updated their beliefs to a greater extent and more frequently when receiving bad news for positive life events, but not for negative life events. Moreover, individuals with high SocAnh also exhibited similar patterns in updating their beliefs for positive life events after controlling depressive symptoms.

CONCLUSIONS

Our findings suggest that negative belief-updating patterns for positive events may play an important role in the formation and maintenance of low-pleasure beliefs in patients with SZ and individuals with high SocAnh.

The Important Role of Motivation and Pleasure Deficits on Social Functioning in Patients With Schizophrenia: A Network Analysis

Negative symptoms, particularly the motivation and pleasure (MAP) deficits, are associated with impaired social functioning in patients with schizophrenia (SCZ). However, previous studies seldom examined the role of the MAP on social functioning while accounting for the complex interplay between other psychopathology. This network analysis study examined the network structure and interrelationship between negative symptoms (at the "symptom-dimension" and "symptom-item" levels), other psychopathology and social functioning in a sample of 269 patients with SCZ. The psychopathological symptoms were assessed using the Clinical Assessment Interview for Negative Symptoms (CAINS) and the Positive and Negative Syndrome Scale (PANSS). Social functioning was evaluated using the Social and Occupational Functioning Assessment Scale (SOFAS). Centrality indices and relative importance of each node were estimated. The network structures between male and female participants were compared. Our resultant networks at both the "symptom-dimension" and the "symptom-item" levels suggested that the MAP factor/its individual items were closely related to social functioning in SCZ patients, after controlling for the complex interplay between other nodes. Relative importance analysis showed that MAP factor accounted for the largest proportion of variance of social functioning. This study is among the few which used network analysis and the CAINS to examine the interrelationship between negative symptoms and social functioning. Our findings supported the pivotal role of the MAP factor to determine SCZ patients' social functioning, and as a potential intervention target for improving functional outcomes of SCZ.

Mapping genomic loci implicates genes and synaptic biology in schizophrenia

Schizophrenia has a heritability of 60-80%1, much of which is attributable to common risk alleles. Here, in a two-stage genome-wide association study of up to 76,755 individuals with schizophrenia and 243,649 control individuals, we report common variant associations at 287 distinct genomic loci. Associations were concentrated in genes that are expressed in excitatory and inhibitory neurons of the central nervous system, but not in other tissues or cell types. Using fine-mapping and functional genomic data, we identify 120 genes (106 protein-coding) that are likely to underpin associations at some of these loci, including 16 genes with credible causal non-synonymous or untranslated region variation. We also implicate fundamental processes related to neuronal function, including synaptic organization, differentiation and transmission. Fine-mapped candidates were enriched for genes associated with rare disruptive coding variants in people with schizophrenia, including the glutamate receptor subunit GRIN2A and transcription factor SP4, and were also enriched for genes implicated by such variants in neurodevelopmental disorders. We identify biological processes relevant to schizophrenia pathophysiology; show convergence of common and rare variant associations in schizophrenia and neurodevelopmental disorders; and provide a resource of prioritized genes and variants to advance mechanistic studies.

Altered brain structural and functional connectivity in schizotypy

BACKGROUND

Schizotypy refers to schizophrenia-like traits below the clinical threshold in the general population. The pathological development of schizophrenia has been postulated to evolve from the initial coexistence of 'brain disconnection' and 'brain connectivity compensation' to 'brain connectivity decompensation'.

METHODS

In this study, we examined the brain connectivity changes associated with schizotypy by combining brain white matter structural connectivity, static and dynamic functional connectivity analysis of diffusion tensor imaging data and resting-state functional magnetic resonance imaging data. A total of 87 participants with a high level of schizotypal traits and 122 control participants completed the experiment. Group differences in whole-brain white matter structural connectivity probability, static mean functional connectivity strength, dynamic functional connectivity variability and stability among 264 brain sub-regions of interests were investigated.

RESULTS

We found that individuals with high schizotypy exhibited increased structural connectivity probability within the task control network and within the default mode network; increased variability and decreased stability of functional connectivity within the default mode network and between the auditory network and the subcortical network; and decreased static mean functional connectivity strength mainly associated with the sensorimotor network, the default mode network and the task control network.

CONCLUSIONS

These findings highlight the specific changes in brain connectivity associated with schizotypy and indicate that both decompensatory and compensatory changes in structural connectivity within the default mode network and the task control network in the context of whole-brain functional disconnection may be an important neurobiological correlate in individuals with high schizotypy.

Prospective Memory Influences Social Functioning in People With First-Episode Schizophrenia: A Network Analysis and Longitudinal Study

Background: Prospective memory (PM) impairment is associated with impaired social functioning, but evidence is limited to chronic schizophrenia samples and cross-sectional design. The aim of this study was to utilize network analysis to address the complex interplay between PM, psychopathology, and functional outcome. Methods: This longitudinal study recruited 119 people with first-episode DSM-IV schizophrenia and followed up with them for 2 to 6 years. PM and working memory were assessed at baseline (in 2010-2015) using valid computerized tasks and the Letter-Number Span Test, respectively. Psychopathology and social functioning were assessed at endpoint (in 2016-2017) using the Positive and Negative Syndrome Scale (PANSS) and the Social and Occupational Functioning Assessment Scale (SOFAS), respectively. Network analysis examined the effect of baseline PM on SOFAS while accounting for the effects of psychopathology. Results: The resultant network showed that social functioning, PANSS positive symptoms, and PANSS general symptoms clustered together, whereas time-based and event-based PM and working memory formed another cluster. Time-based PM linked event-based PM and working memory with social functioning. Time-based PM (expected influence [EI] = 0.69), event-based PM (EI = 0.65), and working memory (EI = 0.83) demonstrated high values of expected influence, but social functioning (variance explained = 0.685) and PANSS negative (variance explained = 0.657) and general (variance explained = 0.583) subscales demonstrated high values of predictability. Conclusions: Time-based PM is the central node linking neurocognitive functions with social functioning. PM and working memory are "target" nodes for interventions bringing changes to the network, whereas social functioning and psychopathology are "malleable" nodes. PM and working memory are promising intervention targets for functional recovery in schizophrenia.

Subclinical psychopathology and affective forecasting: Role of in-the-moment feelings

It is important for positive well-being and social engagement to understand how people predict future emotions, an ability known as affective forecasting. However, mechanisms underpinning the change to affective forecasting are not well understood in people with subclinical psychiatric symptoms. The current study differentiated components that comprise affective forecasting and investigated how non-clinical features relate to these. We recruited 319 participants to complete the social affective forecasting task and respond to questionnaires that captured schizotypal and autistic traits as well as depressive symptoms. Associations between affective forecasting and subclinical features were investigated using correlations, regression, and structure equation modeling. Results showed that interpersonal features of schizotypal traits negatively predicted anticipated emotions in positive social conditions via in-the-moment feelings but not via mental simulation. Findings highlight that in-the-moment feelings may be an intervention target to help people who have difficulties with social interactions to anticipate more pleasure for future social events.

Social brain network predicts real-world social network in individuals with social anhedonia

Social anhedonia (SA) impairs social functioning in schizophrenia. Previous evidence suggested that certain brain regions predict longitudinal change of real-world social outcomes, yet previous study designs have failed to capture the corresponding functional connectivity among the brain regions involved. This study measured the real-world social network in 22 pairs of individuals with high and low levels of SA, and followed up them for 21 months. We further explored whether resting-state social brain network characteristics could predict the longitudinal variations of real-world social network. Our results showed that social brain network characteristics could predict the change of real-world social networks in both the high SA and low SA groups. However, the results differed between the two groups, i.e., the topological characteristics of the social brain network predicted real-world social network change in the high SA group; whereas the functional connectivity within the social brain network predicted real-world social network change in the low SA group. Principal component analysis and linear regression analysis on the entire sample showed that the functional connectivity component centered at the right orbital inferior frontal gyrus could best predict social network change. Our findings support the notion that social brain network characteristics could predict social network development.

Neural mechanisms of prospection in individuals with schizotypal traits, autistic traits, or depressive symptoms

Prospection refers to the ability to mentally construct future events, which is closely related to motivation and anhedonia. The neural underpinning of impaired prospection in psychiatric populations remains unclear. We recruited 34 individuals with autistic traits (AT), 27 individuals with schizotypal traits (ST), 31 individuals with depressive symptoms (DS), and 35 controls. Participants completed a prospection task while undergoing functional Magnetic Resonance Imaging (MRI). We found that regions of the "default mode network" including the medial frontal gyrus, the posterior cingulate cortex, the precuneus and the parahippocampus were activated; and regions of the "task-positive network" including the inferior parietal lobe, the inferior frontal gyrus and the precentral gyrus were deactivated during prospection in controls. Compared with controls, AT, ST, and DS showed comparable behavioral performance on prospection. However, reduced activation in anterior cingulate cortex and frontal gyrus was found in AT individuals relative to controls during prospection. ST individuals showed hyperactivation in the caudate relative to controls when processing positive emotion, while DS individuals and controls showed similar neural responses during prospection. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Altered topographical organization of grey matter structural network in early-onset schizophrenia

Schizophrenia is characterized by both disrupted neurodevelopmental processes and abnormal brain connectivity. However, few studies have examined the atypical features of brain network topography associated with schizophrenia during childhood and adolescence. We used graph theory to compare the grey matter structural networks of individuals (aged 10-15 years) with early-onset schizophrenia (EOS) (n = 25) and a typically-developing (TD) comparison group (n = 31). Compared with the TD group, EOS patients showed significantly increased clustering and local efficiency across a range of network densities (0.3 - 0.4). The network of EOS patients also had more modules (6 modules in EOS vs. 3 modules in controls), indicating a more segregated network at the cost of functional integration. Although our results were preliminary and failed to survive corrections for multiple comparisons, EOS patients might be characterized by altered nodal centrality in several higher-order associative regions including the prefrontal cortex, the hippocampus and the cerebellum. The EOS structural network also lacked the typical left-hemispheric-dominant hub distribution compared with the TD group. These findings suggest that brain structural network was not only globally but also regionally altered in EOS patients.

Range-Adaptive Value Representation in Different Stages of Schizophrenia: A Proof of Concept Study

Amotivation is related to value representation. A comprehensive account of amotivation requires a mechanistic understanding of how the brain exploits external information to represent value. To achieve maximal value discriminability, brain valuation system will dynamically adapt its coding sensitivity to the range of values available in any given condition, so-called range adaptive coding. We administered an experimental task to 30 patients with chronic schizophrenia (C-SCZ), 30 first-episode schizophrenia (FE-SCZ), 34 individuals with high social anhedonia (HSoA), and their paired controls to assess range adaptation ability. C-SCZ patients exhibited over-adaptation and their performances were negatively correlated with avolition symptoms and positive symptoms and positively correlated with blunted-affect symptoms and self-reported consummatory interpersonal pleasure scores, though the results were non-significant. FE-SCZ patients exhibited reduced adaptation, which was significantly and negatively correlated with avolition symptoms and positively correlated with the overall proportion of choosing to exert more effort. Although HSoA participants exhibited comparable range adaptation to controls, their performances were significantly and negatively correlated with the proportion of choosing to exert more effort under the lowest value condition. Our results suggest that different stages of schizophrenia spectrum showed distinct range adaptation patterns. Range adaptation impairments may index a possible underlying mechanism for amotivation symptoms in FE-SCZ and more complicated and pervasive effects on clinical symptoms in C-SCZ.

Different trajectories of neurological soft signs progression between treatment-responsive and treatment-resistant schizophrenia patients

Schizophrenia patients exhibit subtle and non-localizing neurological abnormalities, known as neurological soft signs (NSS). Life-span evidence suggests that NSS vary along the course of schizophrenia. An association between NSS and treatment response has been proposed, suggesting that NSS reflect the underlying neuropathology development in schizophrenia. However, few studies have investigated the relationship between NSS and treatment resistance in first-episode schizophrenia patients. We conducted a longitudinal study on 52 first-episode schizophrenia patients, who were assessed at baseline, the sixth month, and the fifth year using the abridged version of the Cambridge Neurological Inventory. The trajectories of NSS between 29 treatment-responsive patients (with full symptomatic remission) and 23 treatment-resistant patients (who received clozapine) were compared using mixed model ANOVA. We also controlled for the effect of age and estimated IQ, using a mixed ANCOVA model. Although the two schizophrenia groups had comparable NSS at the baseline, their trajectories of NSS differed significantly. Compared with their treatment-responsive counterparts, treatment-resistant schizophrenia patients had worsening of NSS over time. Our findings support the potential utility of NSS in identifying treatment resistance in first-episode schizophrenia. Progressive worsening of NSS in treatment-resistant schizophrenia patients may reflect the development of underlying neuropathology. Further studies using large samples of treatment-resistant schizophrenia patients are needed.

Cognitive insight is correlated with cognitive impairments and contributes to medication adherence in schizophrenia patients

OBJECTIVE

Cognitive insight refers to the ability to distance oneself from and evaluate one's own beliefs and interpretations. Little is known about whether cognitive insight could influence medication adherence in schizophrenia patients. This study examined the role of cognitive insight in medication adherence and how it would interact with neuropsychological functions.

METHODS

Ninety clinically-stable schizophrenia patients completed the Beck's Cognitive Insight Scale (BCIS) and tasks measuring prospective (PM) and other neurocognitive functions. Medication adherence was estimated using a multi-axial method comprising interview, clinician-rating, pharmacy refill record and pill counting. Correlational and regression analyses were conducted to examine whether cognitive insight and PM would be associated with mediation adherence. Post-hoc mediational analysis was performed to examine the interplay between cognitive insight, PM and medication adherence.

RESULTS

Clinical insight and cognitive insight together significantly influenced participants' medication adherence, after neurocognitive functions and psychopathology were accounted for. Time-based PM, compared with other neurocognitive functions, affected medication adherence more strongly.

CONCLUSIONS

Cognitive insight complements clinical insight in affecting medication adherence in schizophrenia patients.

The effect of effort-reward imbalance on brain structure and resting-state functional connectivity in individuals with high levels of schizotypal traits

INTRODUCTION

Effort-reward imbalance (ERI) is a typical psychosocial stress. Schizotypal traits are attenuated features of schizophrenia in the general population. According to the diathesis-stress model, schizotypal traits and psychosocial stress contribute to the onset of schizophrenia. However, few studies examined the effects of these factors on brain alterations. This study aimed to examine relationships between ERI, schizotypal traits and brain structures and functions.

METHODS

We recruited 37 (13 male, 24 female) participants with high levels of schizotypal traits and 36 (12 male, 24 female) participants with low levels of schizotypal traits by the Schizotypal Personality Questionnaire (SPQ). The Chinese school version of the effort-reward imbalance questionnaire (C-ERI-S) was used to measure ERI. We conducted the voxel-based morphometry (VBM) and whole brain resting-state functional connectivity (rsFC) analysis using reward or stress-related regions as seeds.

RESULTS

Participants with high levels of schizotypal traits were more likely to perceive ERI. The severity of ERI was correlated with grey matter volume (GMV) reduction of the left pallidum and altered rsFC among the prefrontal, striatum and cerebellum in participants with high levels of schizotypal traits.

CONCLUSION

ERI is associated with GMV reduction and altered rsFC in individuals with high levels of schizotypal traits.

Altered activation and functional connectivity in individuals with social anhedonia when envisioning positive future episodes

BACKGROUND

Anticipatory pleasure deficits are closely correlated with negative symptoms in schizophrenia, and may be found in both clinical and subclinical populations along the psychosis continuum. Prospection, which is an important component of anticipatory pleasure, is impaired in individuals with social anhedonia (SocAnh). In this study, we examined the neural correlates of envisioning positive future events in individuals with SocAnh.

METHODS

Forty-nine individuals with SocAnh and 33 matched controls were recruited to undergo functional MRI scanning, during which they were instructed to simulate positive or neutral future episodes according to cue words. Two stages of prospection were distinguished: construction and elaboration.

RESULTS

Reduced activation at the caudate and the precuneus when prospecting positive (v. neutral) future events was observed in individuals with SocAnh. Furthermore, compared with controls, increased functional connectivity between the caudate and the inferior occipital gyrus during positive (v. neutral) prospection was found in individuals with SocAnh. Both groups exhibited a similar pattern of brain activation for the construction v. elaboration contrast, regardless of the emotional context.

CONCLUSIONS

Our results provide further evidence on the neural mechanism of anticipatory pleasure deficits in subclinical individuals with SocAnh and suggest that altered cortico-striatal circuit may play a role in anticipatory pleasure deficits in these individuals.

Network analysis of executive function, emotion, and social anhedonia

This study constructed the network structure of social anhedonia, emotion processing, and executive function in college students using network analysis. We calculated the strength of each node in the network. The results suggest that social anhedonia had negative effects on executive function, emotion experience, and emotion expression.

Schizophrenia patients with poor clinical insight report less subjective memory problems

This study aimed to explore the relationships among clinical insight, subjective memory complaints, and objective memory performance in patients with schizophrenia. We recruited 205 patients with schizophrenia and 221 healthy controls in this study. The participants were administered a subjective-report scale on memory (the Prospective and Retrospective Memory Questionnaire), and several objective memory tasks measuring verbal memory, visual memory, and working memory. Clinical insight was measured with an item in the Positive and Negative Syndrome Scale. We found that when patients with schizophrenia were divided into subgroups with good and poor insight, both subgroups showed impairment in memory performance compared with controls. The schizophrenia patients with good insight reported similar memory complaints as controls whereas patients with poor insight reported less memory complaints than did the controls. These findings suggest that clinical insight may be related to subjective memory complaints, but not objective memory performance.

Neurological Soft Signs Are Associated With Altered Cerebellar-Cerebral Functional Connectivity in Schizophrenia

Cerebellar dysfunction is associated with neurological soft signs (NSS), which is a promising endophenotype for schizophrenia spectrum disorders. However, the relationship between cerebellar-cerebral resting-state functional connectivity (rsFC) and NSS is largely unexplored. Moreover, both NSS and cerebellar-cerebral rsFC have been found to be correlated with negative symptoms of schizophrenia. Here, we investigated the correlations between NSS and cerebellar-cerebral rsFC, explored their relationship with negative symptoms in a main dataset, and validated the significant findings in a replication dataset. Both datasets comprised schizophrenia patients and healthy controls. In schizophrenia patients, we found positive correlations between NSS and rsFC of the cerebellum with the inferior frontal gyrus and the precuneus, and negative correlations between NSS and rsFC of the cerebellum with the inferior temporal gyrus. In healthy controls, NSS scores were positively correlated with rsFC of the cerebellum with the superior frontal gyrus and negatively correlated with rsFC between the cerebellum and the middle occipital gyrus. Cerebellar-prefrontal rsFC was also positively correlated with negative symptoms in schizophrenia patients. These findings were validated in the replication dataset. Our results suggest that the uncoupling of rsFC between the cerebellum and the cerebral cortex may underlie the expression of NSS in schizophrenia. NSS-related cerebellar-prefrontal rsFC may be a potential neural pathway for possible neural modulation to alleviate negative symptoms.

Cerebellar hypoactivation is associated with impaired sensory integration in schizophrenia

To clarify the involvement of the cerebellum in impaired sensory integration in patients with schizophrenia, 52 first-episode patients with schizophrenia and 52 age- and sex-matched healthy controls underwent a verified sensory integration imaging task to examine the whole-brain dysfunction underlying impaired sensory integration. The familiality of cerebellar activation when integrating sensory stimuli was investigated in 25 siblings of the patients with schizophrenia, while the heritability of cerebellar activation was estimated in 56 monozygotic twins and 56 dizygotic twins. In addition, the functional connectivity between the cerebellum and the remaining regions of the whole brain was explored with psychophysiological interaction analysis. Relative to healthy controls, patients with schizophrenia showed reduced cerebellar activation when performing the sensory integration task in the whole-brain analysis. This reduced cerebellar activation was also found in the siblings of patients with schizophrenia, but to a lesser extent compared with schizophrenia patients. Cerebellar activation during sensory integration was also found to be significantly heritable. Furthermore, dysconnectivity within the cerebellum was found in patients with schizophrenia when integrating auditory and visual stimuli. These findings highlight the role of cerebellar dysfunction in the pathophysiology of schizophrenia symptoms and its potential role as an endophenotype of schizophrenia spectrum disorders. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Neural Correlates of Audiovisual Temporal Binding Window in Individuals With Schizotypal and Autistic Traits: Evidence From Resting-State Functional Connectivity

Temporal proximity is an important clue for multisensory integration. Previous evidence indicates that individuals with autism and schizophrenia are more likely to integrate multisensory inputs over a longer temporal binding window (TBW). However, whether such deficits in audiovisual temporal integration extend to subclinical populations with high schizotypal and autistic traits are unclear. Using audiovisual simultaneity judgment (SJ) tasks for nonspeech and speech stimuli, our results suggested that the width of the audiovisual TBW was not significantly correlated with self-reported schizotypal and autistic traits in a group of young adults. Functional magnetic resonance imaging (fMRI) resting-state activity was also acquired to explore the neural correlates underlying inter-individual variability of TBW width. Across the entire sample, stronger resting-state functional connectivity (rsFC) between the left superior temporal cortex and the left precuneus, and weaker rsFC between the left cerebellum and the right dorsal lateral prefrontal cortex were correlated with a narrower TBW for speech stimuli. Meanwhile, stronger rsFC between the left anterior superior temporal gyrus and the right inferior temporal gyrus was correlated with a wider audiovisual TBW for non-speech stimuli. The TBW-related rsFC was not affected by levels of subclinical traits. In conclusion, this study indicates that audiovisual temporal processing may not be affected by autistic and schizotypal traits and rsFC between brain regions responding to multisensory information and timing may account for the inter-individual difference in TBW width. LAY SUMMARY: Individuals with ASD and schizophrenia are more likely to perceive asynchronous auditory and visual events as occurring simultaneously even if they are well separated in time. We investigated whether similar difficulties in audiovisual temporal processing were present in subclinical populations with high autistic and schizotypal traits. We found that the ability to detect audiovisual asynchrony was not affected by different levels of autistic and schizotypal traits. We also found that connectivity of some brain regions engaging in multisensory and timing tasks might explain an individual's tendency to bind multisensory information within a wide or narrow time window. Autism Res 2021, 14: 668-680. © 2020 International Society for Autism Research and Wiley Periodicals LLC.

Self-reported sensory responsiveness patterns in typically-developing and early-onset schizophrenia adolescents: Its relationship with schizotypal and autistic traits

Altered behavioural responses to sensory stimuli, including both hypo- and hyper-reactivity, have been found in individuals with schizophrenia. However, how specific sensory responsiveness patterns are associated with symptomatology of schizophrenia remains largely unknown. The present study aimed to examine sensory responsiveness in typically-developing (TD) adolescents (n = 98) and adolescents with early-onset schizophrenia (EOS) (n = 29) and investigate the relationship between schizotypal traits and sensory responsiveness patterns. All participants completed the Adult/Adolescent Sensory Profile (AASP), the Schizotypal Personality Questionnaire (SPQ) and the Autism Spectrum Quotient (AQ). Results showed that higher levels of hypersensitivity and hyposensitivity coexisted in EOS patients and were correlated with positive and negative symptoms of schizophrenia. Atypical sensory experiences except for sensory seeking were found to be positively correlated with higher levels of schizotypal traits regardless of diagnostic status. Moreover, the strength and pattern of such correlations were comparable in both EOS and TD groups. This study also provided evidence that higher levels of autistic traits would intensify the positive correlation between schizotypal traits and sensory responsiveness abnormalities, suggesting an additive effect of co-occurring schizotypal and autistic traits on atypical sensory experiences. These findings extend previous research by depicting sensory responsiveness patterns in younger populations with schizophrenia, and may have implications for future development of sensory-related interventions in clinical settings.

Applying network analysis to investigate the links between dimensional schizotypy and cognitive and affective empathy

BACKGROUND

Although impairment in empathy has been reported in schizophrenia spectrum disorders, little is known about the relationship between empathy and schizotypal traits. This study examines this relationship by applying network analysis to a large sample collected at 18-months follow-up in a longitudinal dataset.

METHODS

One thousand four hundred and eighty-six college students were recruited and completed a set of self-reported questionnaires on empathy, schizotypy, depression, anxiety and stress. Networks were constructed by taking the subscale scores of these measures as nodes and partial correlations between each pair of nodes as edges. Network Comparison Tests were performed to investigate the differences between individuals with high and low schizotypy.

RESULTS

Cognitive and affective empathy were strongly connected with negative schizotypy in the network. Physical and social anhedonia showed high centrality measured by strength, closeness and betweenness while anxiety and stress showed high expected influence. Predictability ranged from 22.4% (personal distress) to 79.9% (anxiety) with an average of 54.4%. Compared with the low schizotypy group, the high schizotypy group showed higher global strength (S = 0.813, p < 0.05) and significant differences in network structure (M = 0.531, p < 0.001) and strength of edges connecting empathy with schizotypy (adjusted ps < 0.05).

LIMITATIONS

Only self-rating scales were used, and disorganized schizotypy was not included.

CONCLUSIONS

Our findings suggest that the cognitive and affective components of empathy and dimensions of schizotypy are closely related in the general population and their network interactions may play an important role in individuals with high schizotypy.

Altered default mode network functional connectivity in individuals with co-occurrence of schizotypy and obsessive-compulsive traits

In this study, we examined differences in resting-state functional connectivity between sub-regions of the Default Mode Network (DMN) and whole brain voxels in 22 individuals with high schizo-obsessive traits (SOT), 30 with high schizotypal traits (SCT) alone, 20 with high obsessive-compulsive traits (OCT) alone and 30 with low trait scores (LT). We found that the SOT group showed the most reduced functional connectivity within the DMN compared with the other groups. The SOT group also showed increased connectivity between the DMN and the Salience Network, and between the DMN and the Auditory Network compared with the LT group. The SCT group exhibited increased connectivity between the DMN and the Salience Network, and between the DMN and the Executive Control Network (ECN) compared with the LT group. The OCT group exhibited decreased connectivity within the DMN, between the DMN and the Salience Network, and between the DMN and the ECN compared with the LT group. These findings highlight different changes in DMN-related functional connectivity associated with high SOT, SCT and OCT traits and may provide insight into the dysfunctional brain networks in the early stage of schizophrenia spectrum disorders.

The role of lipoprotein profile in depression and cognitive performance: a network analysis

Lipid profile (total cholesterol and lipoprotein fractions) has been found to correlate with depression and cognitive impairment across the lifespan. However, the role of lipid levels in self-rated depressive state and cognitive impairment remains unclear. In this study, we examined the relationship between lipid profile (total cholesterol, triglycerides, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol) and cognition in adults with and without self-rated depression. Four hundred and thirty-eight healthy participants completed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), the Self-Rating Depression Scale (SDS), and a serum lipoprotein test. Using multivariate ANOVA, partial correlation and network analysis, a network linking lipoprotein profile, depressive state and cognition was constructed. A significant difference in serum lipid profile between the high and low depressive groups was detected. Depressive state had a strong negative correlation with cognitive performance. Of the lipid profile, only high-density lipoprotein was positively correlated with depressive symptom severity, whereas the other three indices showed negative correlation with both depressive state and cognitive performance. Our results suggest that serum lipid profile may be directly linked to self-rated depression and cognitive performance. Further studies recruiting larger clinical samples are needed to elucidate the specific effect of lipoprotein on cognitive impairment in mood disorder.

Grey matter volume and structural covariance associated with schizotypy

In this study, we applied brain grey matter volume and structural covariance methods on T1 weighted images to delineate potential structural brain changes in individuals with high schizotypy, who were defined as healthy individuals scoring in the top tenth percentile of the Schizotypal Personality Questionnaire (SPQ). Eighty-seven college students with high schizotypy and 122 controls were recruited in China. Differences in grey matter volume and volume covariance between the two groups, and correlations of grey matter volume with SPQ scores in the high schizotypy group were examined. We found that individuals with high schizotypy had decreased grey matter volume at the left medial superior frontal gyrus (medsFG) extending towards the superior frontal gyrus, decreased structural covariance within the right medsFG, between the right superior frontal gyrus (sFG), the right superior temporal gyrus and the right anterior insula; and increased structural covariance between the caudate and the right inferior temporal gyrus. Correlation analysis revealed that grey matter volume of the left middle temporal pole and the right sFG correlated positively with the SPQ total scores, volume of the bilateral cerebellum 9 sub-region correlated negatively with the SPQ cognitive-perceptual sub-scale scores, volume of the bilateral striatum correlated positively with the SPQ interpersonal sub-scale scores, and volume of the bilateral superior temporal pole correlated positively with the SPQ disorganization sub-scale scores in the high schizotypy group. These results highlight important grey matter structural changes in the medsFG in individuals with high schizotypy.

Altered empathy-related resting-state functional connectivity in adolescents with early-onset schizophrenia and autism spectrum disorders

Empathy refers to the ability to understand other people's feelings and reacting emotionally to others. Impaired empathy has been reported in both individuals with schizophrenia and autism spectrum disorders (ASD). Despite overlaps, few studies have directly examined the neural mechanisms of impaired empathy in these two clinical groups. We used resting-state fMRI to investigate the neural correlates of empathic functioning in adolescents with ASD (N = 11), early-onset schizophrenia (EOS) (N = 20), and typically developing (TD) controls (N = 26). Their parents completed the Griffith Empathy Measure (GEM) to assess the adolescents' empathic capacity. We found that EOS and ASD participants both exhibited impaired empathy as measured by the GEM, especially in cognitive empathy (post-hoc ps < 0.05). Regions-of-interest-based functional connectivity revealed decreased connectivity between the salience network (SN) (i.e., the anterior insula and the anterior cingulate cortex) and core regions of the mentalizing network (e.g., the temporal-parietal junction and the precuneus), and among the SN and the bilateral superior temporal gyri (STG) and the left cerebellum in EOS participants. Subsequent comparisons revealed reduced grey matter volume in the STG bilaterally in both clinical groups. Increased resting-state functional connectivity within the social brain network was correlated with higher parent-reported scores of empathic capacity in TD adolescents, but such a brain-phenotype relationship was absent in the two clinical groups. These findings indicate that structural alterations and disturbed resting-state functional connectivity in the core empathy network may be the neural correlates of social cognitive deficits in individuals with EOS and ASD.

Altered cerebellocerebral structural covariance in individuals with attenuated psychosis syndrome

BACKGROUND

Reduced cerebellar volumes and altered cerebellocerebral structural covariance have been reported in patients with schizophrenia. However, it is not clear whether such altered cerebellocerebral structural covariance would be observed before the onset of psychosis. We examined brain structural changes, including cerebral and cerebellar volumes, and cerebellocerebral structural covariance in individuals with attenuated psychosis syndrome (APS).

MATERIALS AND METHODS

Twenty-one individuals with APS and 24 healthy controls (HC) were recruited and underwent structural MRI brain scan. Differences in voxel-based grey matter (GM) volume and cerebellar volume between the APS and HC groups were examined. The correlation between cerebellar volumes and voxel-based cerebral GM volumes were calculated to measure cerebellocerebral structural covariance in each group followed by group comparisons.

RESULTS

Compared with HC, individuals with APS exhibited extensive GM volume reduction in the frontal and striatal areas and reduced cerebellar volume. Structural covariance analysis indicated that the anterior and posterior parts of the cerebellum showed disparate correlation with cerebral voxel-based GM volumes. Abnormal cerebellar-cerebral correlation was also found in individuals with APS at the medial prefrontal gyrus.

CONCLUSIONS

Our findings suggest that prefrontal and striatal structural changes as well as cerebellar structural covariance at the medial prefrontal gyrus may underpin the risk for psychosis and may serve as a potential target for early intervention in individuals at-risk for psychosis.

Resting frontal EEG asymmetry and schizotypal traits: a test-retest study

Introduction: Increase in right relative to left frontal electroencephalography (EEG) activity has been observed in patients with schizophrenia, both in cognitive tasks and during rest; and this lateralisation may be related to the severity of schizotypal traits. Methods: We used the Schizotypal Personality Questionnaire (SPQ) to assess schizotypal traits, and examined the correlation between these traits and resting EEG frontal asymmetry (left-right) in 52 college students, as well as the reliability of this correlation over a three-month interval. Results: A higher total score on the SPQ was correlated with reduced asymmetry in different frequency bands: gamma and beta2 frequency bands at baseline, and delta and alpha frequency bands three months later. Additionally, the reduced left relative to right frontal gamma and beta2 asymmetry was correlated with the participants' verbal fluency ability. However, this correlation was no longer statistically significant after the total SPQ score was controlled. Conclusions: These findings suggest that resting frontal EEG asymmetry is correlated with powers in different frequency bands, and may be an endophenotype for schizophrenia spectrum disorders.

Altered grey matter volume and white matter integrity in individuals with high schizo-obsessive traits, high schizotypal traits and obsessive-compulsive symptoms

Altered brain structures have been found in patients with schizo-obsessive disorder, schizophrenia and obsessive-compulsive disorder in previous studies. However, it is unclear whether similar brain changes are also found in individuals with high schizo-obsessive traits (SOT), high schizotypal traits (SCT) and obsessive-compulsive symptoms (OCS). We examined grey matter volume (GMV) and white matter integrity (WMI, including fractional anisotropy, mean diffusivity, axial diffusivity and radial diffusivity) in 26 individuals with high SOT, 30 individuals with high SCT, 25 individuals with OCS and 30 individuals with low trait scores (LT) in this study. Correlation analysis between GMV, WMI, Schizotypal Personality Questionnaire (SPQ) scores and Obsessive-Compulsive Inventory-Revised (OCI-R) scores in the subclinical groups was also carried out. We found that the SOT group exhibited increased GMV at the right superior occipital gyrus and the left postcentral gyrus compared with the LT group. The SCT group exhibited increased GMV at the right precentral gyrus and the bilateral cuneus compared with the LT group, and decreased fractional anisotropy at the anterior corona radiata compared with the other three groups. The OCS group exhibited increased GMV at the left superior temporal gyrus and decreased GMV at the left pre-supplementary motor area compared with the LT group. These findings highlight specific brain changes in individuals with high SOT, high SCT and OCS, and may thus provide new insights into the neurobiological changes that occur in sub-clinical populations of these disorders.

Schizotypal and obsessive-compulsive traits: Co-occurrence rate and relationship with executive function, emotion experience, and emotion expressivity in college students

Empirical findings suggest that there is an overlap between schizophrenia and obsessive-compulsive disorder (OCD). These disorders also have a high comorbidity rate. However, little is known about the impact of co-occurring schizotypal and obsessive-compulsive traits on executive function, emotion experience, and emotion expressivity in the normal population. The present study examined the prevalence of coexisting schizotypal and obsessive-compulsive traits and the relationship between these two traits in a sample of healthy college students. We also conducted a moderation analysis to explore the effect of these two type of traits on executive function, emotion experience, and emotion expressivity. We recruited 3,319 participants to complete the Schizotypal Personality Questionnaire (SPQ) and the Obsessive-Compulsive Inventory - Revised (OCI-R). A subset of them (n = 575) also completed the Chinese versions of the Dysexecutive Questionnaire (DEX), the Temporal Experience of Pleasure Scale (TEPS), and the Emotional Expressivity Scale (EES). We found that the prevalence of co-occurring schizotypal and OCD traits was 3.33%. All the subscales of the SPQ and the OCI-R significantly correlated with each other. Both traits had a negative impact on executive function and emotion expressivity. The interaction between the disorganization dimension of schizotypal traits and OCD traits had a significant effect on executive function, but not emotion experience or emotion expressivity. This study was limited by its cross-sectional design and recruitment of only college students. These findings suggest that there is an approximately 3% rate of co-occurring schizotypal and obsessive-compulsive traits in a healthy college student sample. The interaction between these two types of traits may influence executive function.

Exploring the links between alexithymia, empathy and schizotypy in college students using network analysis

Introduction: Impaired empathy is one of the major dysfunctions commonly found in patients with schizophrenia, with alexithymia being one possible underlying factor. Schizotypy represents a set of psychotic-like manifestations, investigation of which may contribute to our understanding of psychosis while minimising the confounding effects of illness chronicity and medication exposure. Few studies have specifically examined the associations among alexithymia, empathy and schizotypy. Methods: We investigated the relationships among alexithymia, empathy and schizotypy in college students using network analysis. The Interpersonal Reactivity Index (IRI), Toronto Alexithymia Scale (TAS), and Chapman Psychosis-Proneness scales were captured, and network based on the subscales were estimated in 552 participants. Strength, closeness and betweenness of nodes were calculated to measure the centrality. Results: Network analyses revealed a pattern connecting alexithymia with empathy and schizotypy. Negative connections between empathy and physical/social anhedonia and positive edges linking alexithymia with empathy and social anhedonia were observed. Conclusions: Network constructed in the study demonstrated alexithymia's role in empathic deficits. Our findings highlighted the connections between components of empathy, alexithymia and schizotypy.

Validation of the Chinese version of the Multidimensional Schizotypy Scale (MSS): Convergent evidence from exploratory and confirmatory factor analyses

BACKGROUND

Schizotypy has been shown to be a time-stable construct that exists across the schizophrenia spectrum. The Multidimensional Schizotypy Scale (MSS) was developed to capture the three factors underlying schizotypy: positive, disorganized and negative schizotypy. However, a recent validation study reported a four-factor construct with an additional negative social anhedonia factor. The factor structure of the Chinese version of the MSS remains unknown. This study aimed to identify and validate the factor structure of the Chinese version of the MSS.

METHODS

We recruited 641 Chinese speakers via on-line advertisement. We administered the Chinese version of the MSS, which was a self-report instrument. The scale consists of 77 items with true or false response options. We identified and removed 43 outliers. Finally, a total of 294 participants were randomly selected as the derivative sample for exploratory factor analysis (EFA). The remaining 304 participants were retained as the validation sample for confirmatory factor analysis (CFA).

RESULTS

EFA identified four factors: the positive factor, the disorganization factor, the negative affective and motivational anhedonia factor, and the negative social anhedonia factor. The EFA-identified four-factor model was compared with the unidimensional, three-factor bifactorial and theoretical three-factor models using CFAs. The three-factor bifactorial model fitted the data better than the EFA-identified four-factor model.

CONCLUSION

Our finding suggests that the Chinese version of the MSS is a valid tool for assessing schizotypy in the Chinese setting.

Neurological Soft Signs and Brain Network Abnormalities in Schizophrenia

Neurological soft signs (NSS) are often found in patients with schizophrenia. A wealth of neuroimaging studies have reported that NSS are related to disturbed cortical-subcortical-cerebellar circuitry in schizophrenia. However, the association between NSS and brain network abnormalities in patients with schizophrenia remains unclear. In this study, the graph theoretical approach was used to analyze brain network characteristics based on structural magnetic resonance imaging (MRI) data. NSS were assessed using the Heidelberg scale. We found that there was no significant difference in global network properties between individuals with high and low levels of NSS. Regional network analysis showed that NSS were associated with betweenness centrality involving the inferior orbital frontal cortex, the middle temporal cortex, the hippocampus, the supramarginal cortex, the amygdala, and the cerebellum. Global network analysis also demonstrated that NSS were associated with the distribution of network hubs involving the superior medial frontal cortex, the superior and middle temporal cortices, the postcentral cortex, the amygdala, and the cerebellum. Our findings suggest that NSS are associated with alterations in topological attributes of brain networks corresponding to the cortical-subcortical-cerebellum circuit in patients with schizophrenia, which may provide a new perspective for elucidating the neural basis of NSS in schizophrenia.

Validation and extension of the Motivation and Pleasure Scale-Self Report (MAP-SR) across the schizophrenia spectrum in the Chinese context

BACKGROUND

Developed based on the Clinical Assessment Interview for Negative Symptoms (CAINS), the Motivation and Pleasure Scale-Self Report (MAP-SR) was designed to address the conceptual and psychometric limitations of other instruments assessing negative symptoms. We sought to validate and extend the applicability of the MAP-SR in the Chinese context across the schizophrenia spectrum.

METHODS

Three samples, including college students, individuals with social anhedonia and patients with schizophrenia, were recruited. Test-retest reliability, internal consistency, factor structure, and convergent/discriminant validity of the MAP-SR were examined. The group differences between the three participant groups were examined.

RESULTS

A four-factor structure of the MAP-SR was found consistently in all three groups of participants. The scale showed convergent/discriminant validity in patients with schizophrenia and individuals with social anhedonia, along with good reliability found in schizophrenia patients. The MAP-SR was also able to distinguish individuals with SocAnh and patients with SZ from matched controls.

CONCLUSIONS

The MAP-SR is a valid and reliable instrument in assessing negative symptoms in individuals along the schizophrenia spectrum.

Impaired olfactory identification and hedonic judgment in schizophrenia patients with prominent negative symptoms

Introduction: Evidence suggests that schizophrenia patients have olfactory dysfunctions, but the relationship between olfactory identification, hedonic judgement, and negative symptomatology remains unclear. Few studies have investigated whether co-activation of pleasant and unpleasant emotions are more prevalent in schizophrenia patients.Methods: Thirty schizophrenia outpatients with prominent negative symptoms (PNS), 30 outpatients without PNS, and 30 controls completed the University of Pennsylvania Smell Identification Test, and were asked to identify the odourants and to rate their emotions. The effects of gender and medications on olfactory function were examined.Results: Schizophrenia patients exhibited olfactory identification impairments, even after accounting for gender and medication effects. Patients with PNS demonstrated larger magnitude of deficit than those without. Patients with PNS reported less pleasure to positive-valenced odourants, and less unpleasantness to negative-valenced odourants than controls. Olfactory anhedonia in patients with PNS disappeared after controlling for medication effect. Schizophrenia patients do not exhibit affective ambivalence in olfaction.Conclusions: Schizophrenia patients with PNS exhibit deficits in olfactory identification and hedonic judgement, even after controlling for gender and medication effects. Our findings support the close relationship between olfactory dysfunctions and negative symptoms. Further studies should investigate the effect of dopamine-blocking agents on the olfactory hedonic judgment in schizophrenia patients.

Audiovisual temporal integration: Cognitive processing, neural mechanisms, developmental trajectory and potential interventions

To integrate auditory and visual signals into a unified percept, the paired stimuli must co-occur within a limited time window known as the Temporal Binding Window (TBW). The width of the TBW, a proxy of audiovisual temporal integration ability, has been found to be correlated with higher-order cognitive and social functions. A comprehensive review of studies investigating audiovisual TBW reveals several findings: (1) a wide range of top-down processes and bottom-up features can modulate the width of the TBW, facilitating adaptation to the changing and multisensory external environment; (2) a large-scale brain network works in coordination to ensure successful detection of audiovisual (a)synchrony; (3) developmentally, audiovisual TBW follows a U-shaped pattern across the lifespan, with a protracted developmental course into late adolescence and rebounding in size again in late life; (4) an enlarged TBW is characteristic of a number of neurodevelopmental disorders; and (5) the TBW is highly flexible via perceptual and musical training. Interventions targeting the TBW may be able to improve multisensory function and ameliorate social communicative symptoms in clinical populations.

Identifying Schizo-Obsessive Comorbidity by Tract-Based Spatial Statistics and Probabilistic Tractography

A phenomenon in schizophrenia patients that deserves attention is the high comorbidity rate with obsessive-compulsive disorder (OCD). Little is known about the neurobiological basis of schizo-obsessive comorbidity (SOC). We aimed to investigate whether specific changes in white matter exist in patients with SOC and the relationship between such abnormalities and clinical parameters. Twenty-eight patients with SOC, 28 schizophrenia patients, 30 OCD patients, and 30 demographically matched healthy controls were recruited. Using Tract-based Spatial Statistics and Probabilistic Tractography, we examined the pattern of white matter abnormalities in these participants. We also used ANOVA and Support Vector Classification of various white matter indices and structural connection probability to further examine white matter changes among the 4 groups. We found that patients with SOC had decreased fractional anisotropy (FA) and increased radial diffusivity in the right sagittal stratum and the left crescent of the fornix/stria terminalis compared with healthy controls. We also found changed connection probability in the Default Mode Network, the Subcortical Network, the Attention Network, the Task Control Network, the Visual Network, the Somatosensory Network, and the cerebellum in the SOC group compared with the other 3 groups. The classification results further revealed that FA features could differentiate the SOC group from the other 3 groups with an accuracy of .78. These findings highlight the specific white matter abnormalities found in patients with SOC.

Revisiting anticipatory hedonic processing in patients with schizophrenia: An examination between representation activation and maintenance

BACKGROUND

Anticipatory anhedonia is one of the key deficits found in patients with schizophrenia (SCZ). However, the underlying mechanism of this deficit remains unclear. The present study examined whether representation activation and maintenance capacity influenced anticipatory experiences in SCZ patients.

METHODS

We recruited 46 SCZ patients (26 males) and 45 matched healthy controls (24 males). The Reward Representation Activation and Maintenance (RRAM) Task was administrated to assess anticipatory experience and representation activation and maintenance capacity.

RESULTS

SCZ patients exhibited lower subjective arousal than controls in anticipation of rewards with high probability when representation activation and maintenance were difficult to accomplish. SCZ patients also tended to reduce their button presses more than HC when they were required to maintain reward representation.

CONCLUSIONS

Our findings suggest that representation activation and maintenance may partially account for anticipatory anhedonia observed in SCZ patients.

Affective forecasting in individuals with social anhedonia: The role of social components in anticipated emotion, prospection and neural activation

BACKGROUND

Affective forecasting, or the ability to forecast emotional responses to future events, is essential to everyday life adaption. Previous research suggests that individuals with social anhedonia exhibit deficits in affective forecasting, but the pattern of these deficits and their neural correlates are not known.

METHODS

Individuals with social anhedonia (n = 40) and healthy controls (n = 46) completed a social affective forecasting task and underwent resting-state fMRI scanning.

RESULTS

Compared with healthy controls, social anhedonia individuals anticipated reduced pleasure especially in social conditions and their prospection contained less visualization, voice, taste, self-referential thoughts, other-referential thoughts and language communication. Moreover, anticipated pleasure (valence and arousal for positive events) was positively associated with effort level, especially in social conditions. The social anhedonia group also exhibited stronger functional connectivity between the retrosplenial cortex and the insula and reduced functional connectivity between the hippocampal formation and the parahippocampus. These altered functional connectivities were correlated with anticipated valence in social, but not non-social, conditions.

CONCLUSIONS

These findings suggest that individuals with social anhedonia anticipate less pleasure predominately in social conditions and impaired prospection may contribute to the reduced anticipated pleasure. Reduced anticipated pleasure may be a target to improve social motivation in social anhedonia individuals.

Generalizability of machine learning for classification of schizophrenia based on resting-state functional MRI data

Machine learning has increasingly been applied to classification of schizophrenia in neuroimaging research. However, direct replication studies and studies seeking to investigate generalizability are scarce. To address these issues, we assessed within-site and between-site generalizability of a machine learning classification framework which achieved excellent performance in a previous study using two independent resting-state functional magnetic resonance imaging data sets collected from different sites and scanners. We established within-site generalizability of the classification framework in the main data set using cross-validation. Then, we trained a model in the main data set and investigated between-site generalization in the validated data set using external validation. Finally, recognizing the poor between-site generalization performance, we updated the unsupervised algorithm to investigate if transfer learning using additional unlabeled data were able to improve between-site classification performance. Cross-validation showed that the published classification procedure achieved an accuracy of 0.73 using majority voting across all selected components. External validation found a classification accuracy of 0.55 (not significant) and 0.70 (significant) using the direct and transfer learning procedures, respectively. The failure of direct generalization from one site to another demonstrates the limitation of within-site cross-validation and points toward the need to incorporate efforts to facilitate application of machine learning across multiple data sets. The improvement in performance with transfer learning highlights the importance of taking into account the properties of data when constructing predictive models across samples and sites. Our findings suggest that machine learning classification result based on a single study should be interpreted cautiously.

Network structure of anticipatory pleasure and risk features: Evidence from a large college sample

Investigating the relationship between anticipatory pleasure deficits and risk features of mental disorders not only theoretically benefits the understanding of anhedonia, but could also facilitate early detection and intervention of mental disorders. Using network analysis, the present study examined the pattern of relationship between anticipatory pleasure and risk features of schizophrenia spectrum, depressive, anxiety, autism spectrum, and obsessive-compulsive disorders in a large sample of college students (n = 2152). It was found that interpersonal features of schizotypal personality traits and poor social skills of autistic traits showed strong correlation with low social anticipatory pleasure. Depressive symptoms severity was weakly associated with reduced abstract anticipatory pleasure, while obsessive-compulsive traits were weakly associated with high contextual anticipatory pleasure. No significant correlation was found between anxiety symptoms severity and anticipatory pleasure. Social anticipatory pleasure had the highest strength centrality among all anticipatory pleasure components, while interpersonal features of schizotypal personality traits had the highest strength centrality in the whole network. Our findings suggest that impaired anticipatory pleasure, especially social anticipatory pleasure, is a particular feature of schizotypal personality traits and autistic traits. Our findings may have implications for intervention in that the social component may be a target to improve anhedonia in individuals with schizotypal and autistic traits, while interpersonal features may be a key treatment target given that it was central to the relationship between anticipatory pleasure and risk features.

Audiovisual temporal integration and rapid temporal recalibration in adolescents and adults: Age-related changes and its correlation with autistic traits

Temporal structure is a key factor in determining the relatedness of multisensory stimuli. Stimuli that are close in time are more likely to be integrated into a unified perceptual representation. To investigate the age-related developmental differences in audiovisual temporal integration and rapid temporal recalibration, we administered simultaneity judgment (SJ) tasks to a group of adolescents (11-14 years) and young adults (18-28 years). No age-related changes were found in the width of the temporal binding window within which participants are highly likely to combine multisensory stimuli. The main distinction between adolescents and adults was audiovisual temporal recalibration. Although participants of both age groups could rapidly recalibrate based on the previous trial for speech stimuli (i.e., syllable utterances), only adults but not adolescents showed short-term recalibration for simple and non-speech stimuli. In both adolescents and adults, no significant correlation was found between audiovisual temporal integration ability and autistic or schizotypal traits. These findings provide new information on the developmental trajectory of basic multisensory function and may have implications for neurodevelopmental disorders (e.g., autism) with altered audiovisual temporal integration. Autism Res 2020, 13: 615-626. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Utilizing temporal cues to integrate and separate audiovisual information is a fundamental ability underlying higher order social communicative functions. This study examines the developmental changes of the ability to detect audiovisual asynchrony and rapidly adjust sensory decisions based on previous sensory input. In healthy adolescents and young adults, the correlation between autistic traits and audiovisual integration ability failed to reach a significant level. Therefore, more research is needed to examine whether impairment in basic sensory functions is correlated with broader autism phenotype in nonclinical populations. These results may help us understand altered multisensory integration in people with autism.