Is it possible to be schizophrenic yet neuropsychologically normal?

The impact of aerobic endurance training on cognitive performance in schizophrenic inpatients in a clinical routine setting

The primary aim of this study was to investigate the impact of aerobic endurance training in schizophrenic inpatients on cognitive performance in a clinical routine setting. Of secondary interest was the influence on psychopathological symptoms. A total of 31 schizophrenic inpatients were randomly assigned to receive either controlled endurance training or occupational therapy. The experimental group underwent endurance training of 20-30 min each, 3 times per week for a total of up to 22 training sessions. The control group received about 90 min of occupational therapy, 2-3 times per week for up to 22 sessions. Cognitive performance was assessed via an extensive neuropsychological examination before randomization and prior to discharge. Significant improvements in cognitive functions and psychopathology could be shown in both groups. For verbal memory functions (short-term memory, working memory, and learning performance), there was a significant advantage for the aerobic endurance training group. Physical exercise is a feasible, easy-to-implement add-on therapy for schizophrenic patients in a clinical routine setting with positive effects on verbal memory functions. Besides, it seems important to fill the gap between inpatient and outpatient health care, providing physical training supply for this patient group.

Functional magnetic resonance imaging in schizophrenia: current evidence, methodological advances, limitations and future directions

Functional neuroimaging emerged with great promise and has provided fundamental insights into the neurobiology of schizophrenia. However, it has faced challenges and criticisms, most notably a lack of clinical translation. This paper provides a comprehensive review and critical summary of the literature on functional neuroimaging, in particular functional magnetic resonance imaging (fMRI), in schizophrenia. We begin by reviewing research on fMRI biomarkers in schizophrenia and the clinical high risk phase through a historical lens, moving from case-control regional brain activation to global connectivity and advanced analytical approaches, and more recent machine learning algorithms to identify predictive neuroimaging features. Findings from fMRI studies of negative symptoms as well as of neurocognitive and social cognitive deficits are then reviewed. Functional neural markers of these symptoms and deficits may represent promising treatment targets in schizophrenia. Next, we summarize fMRI research related to antipsychotic medication, psychotherapy and psychosocial interventions, and neurostimulation, including treatment response and resistance, therapeutic mechanisms, and treatment targeting. We also review the utility of fMRI and data-driven approaches to dissect the heterogeneity of schizophrenia, moving beyond case-control comparisons, as well as methodological considerations and advances, including consortia and precision fMRI. Lastly, limitations and future directions of research in the field are discussed. Our comprehensive review suggests that, in order for fMRI to be clinically useful in the care of patients with schizophrenia, research should address potentially actionable clinical decisions that are routine in schizophrenia treatment, such as which antipsychotic should be prescribed or whether a given patient is likely to have persistent functional impairment. The potential clinical utility of fMRI is influenced by and must be weighed against cost and accessibility factors. Future evaluations of the utility of fMRI in prognostic and treatment response studies may consider including a health economics analysis.

Improving autobiographical memory in schizophrenia using wearable cameras: A single-case experimental study

Autobiographical memory (AM) impairments influence both sense of identity and social functioning of patients with schizophrenia. However, cognitive remediation methods addressing these difficulties do not sufficiently consider the heterogeneity of this disorder and frequently face methodological limitations. The aim of the present study was to evaluate the efficacy of a method using a wearable camera (NarrativeClip®), through an alternating treatments design across two types of AM training. In parallel, repeated measures were used to appreciate the efficacy, specificity, and generalizability of the programme's benefits. Three patients were invited to wear the camera during 24 personal events. Ten of these events memories were trained by visual cueing (wearable camera condition), 10 others by verbal cueing (written diary condition) and 4 were not trained (control condition). Using pictures collected by the wearable camera seemed particularly relevant, since it promoted more detailed recalls than the diary method, from the first training session and until the end of a one-year follow-up. In addition, the repeated measures performed revealed (1) the efficacy (improvement in AM capacities after participating in the programme), (2) specificity (persistence of working memory deficits), and (3) generalizability (improvement in measures of episodic memory) of our cognitive remediation programme's effects.

Amyloid-β Deposition Predicts Grocery Shopping Performance in Older Adults Without Cognitive Impairment

Background

A screening tool sensitive to Alzheimer's disease (AD) risk factors, such as amyloid-β (Aβ) deposition, and subtle cognitive changes, best elicited by complex everyday tasks, is needed.

Objective

To determine if grocery shopping performance could differentiate older adults at elevated risk of developing AD (OAer), older adults at low risk of developing AD (OAlr), and young adults (YA), and if amount of Aβ deposition could predict grocery shopping performance in older adults (OA).

Methods

Twenty-one OAer (78±5 years), 33 OAlr (78±5 years), and 28 YA (31±3 years) performed four grocery shopping trials, with the best and worst performances analyzed. Measures included trial time, number of correct items, number of grocery note fixations, and number of fixations and percentage of time fixating on the correct shelving unit, correct brand, and correct shelf. Linear mixed effects models compared measures by performance rank (best, worst) and group (OAer, OAlr, YA), and estimated the effect of Aβ deposition on measures in OA.

Results

Relative to their best performance, OAer and OAlr exhibited more correct shelving unit fixations and correct brand fixations during their worst performance, while YA did not. Within OA's worst performance, greater Aβ deposition was associated with a smaller percentage of time fixating on the correct shelving unit, correct shelf, and correct brand. Within OA, greater Aβ deposition was associated with more grocery note fixations.

Conclusions

OA with elevated Aβ deposition may exhibit subtle working memory impairments and less efficient visual search strategies while performing a cognitively demanding everyday task.

Prevalence of cognitive impairments and strengths in the early course of psychosis and depression

BACKGROUND

Studies investigating cognitive impairments in psychosis and depression have typically compared the average performance of the clinical group against healthy controls (HC), and do not report on the actual prevalence of cognitive impairments or strengths within these clinical groups. This information is essential so that clinical services can provide adequate resources to supporting cognitive functioning. Thus, we investigated this prevalence in individuals in the early course of psychosis or depression.

METHODS

A comprehensive cognitive test battery comprising 12 tests was completed by 1286 individuals aged 15-41 (mean age 25.07, s.d. 5.88) from the PRONIA study at baseline: HC (N = 454), clinical high risk for psychosis (CHR; N = 270), recent-onset depression (ROD; N = 267), and recent-onset psychosis (ROP; N = 295). Z-scores were calculated to estimate the prevalence of moderate or severe deficits or strengths (>2 s.d. or 1-2 s.d. below or above HC, respectively) for each cognitive test.

RESULTS

Impairment in at least two cognitive tests was as follows: ROP (88.3% moderately, 45.1% severely impaired), CHR (71.2% moderately, 22.4% severely impaired), ROD (61.6% moderately, 16.2% severely impaired). Across clinical groups, impairments were most prevalent in tests of working memory, processing speed, and verbal learning. Above average performance (>1 s.d.) in at least two tests was present for 40.5% ROD, 36.1% CHR, 16.1% ROP, and was >2 SDs in 1.8% ROD, 1.4% CHR, and 0% ROP.

CONCLUSIONS

These findings suggest that interventions should be tailored to the individual, with working memory, processing speed, and verbal learning likely to be important transdiagnostic targets.

Early-onset schizophrenia: studying the links between cognitive and clinical dimensions

BACKGROUND

Early-onset schizophrenia (EOS), a rare and severe chronic psychiatric condition, is defined by an onset of schizophrenia symptoms before the age of 18. Core symptoms also include cognitive impairments. However, little is known about links between psychiatric symptoms of EOS and cognitive abilities.

OBJECTIVE

To explore the clinical and neurocognitive profiles of EOS patients and their links.

METHOD

EOS patients have been phenotyped using standardised psychiatric assessments for DSM-5 diagnoses (K-SADS-PL) and for symptoms (PANSS and SANS), together with neurocognitive evaluations.

RESULTS

The EOS sample (n = 27, 12.4 +/-3.2 years) presented hallucinations (83%), negative symptoms (70%) and delusion (59%). 81% of patients presented comorbidities such as anxiety disorders (33%), autism spectrum disorder (26%) and attention-deficit hyperactivity disorder (26%). Patients presented borderline intellectual deficiency (total IQ = 72.5 +/-4.7), with low performances in working memory subtest. We highlight a positive correlation between the IQ and intensity of positive symptoms (PANSS) and between the IQ and a first treatment being administered at an older age. We also highlight a negative correlation between the IQ and attention items of SANS.

CONCLUSION

Cognitive skills are correlated with symptom intensity in EOS patients. An older age of onset seems to be a protective factor for cognitive development.

Brain subnetworks most sensitive to alterations of functional connectivity in Schizophrenia: a data-driven approach

Functional connectivity (FC) of the brain changes in various brain disorders. Its complexity, however, makes it difficult to obtain a systematic understanding of these alterations, especially when they are found individually and through hypothesis-based methods. It would be easier if the variety of brain connectivity alterations is extracted through data-driven approaches and expressed as variation modules (subnetworks). In the present study, we modified a blind approach to determine inter-group brain variations at the network level and applied it specifically to schizophrenia (SZ) disorder. The analysis is based on the application of independent component analysis (ICA) over the subject's dimension of the FC matrices, obtained from resting-state functional magnetic resonance imaging (rs-fMRI). The dataset included 27 SZ people and 27 completely matched healthy controls (HC). This hypothesis-free approach led to the finding of three brain subnetworks significantly discriminating SZ from HC. The area associated with these subnetworks mostly covers regions in visual, ventral attention, and somatomotor areas, which are in line with previous studies. Moreover, from the graph perspective, significant differences were observed between SZ and HC for these subnetworks, while there was no significant difference when the same parameters (path length, network strength, global/local efficiency, and clustering coefficient) across the same limited data were calculated for the whole brain network. The increased sensitivity of those subnetworks to SZ-induced alterations of connectivity suggested whether an individual scoring method based on their connectivity values can be applied to classify subjects. A simple scoring classifier was then suggested based on two of these subnetworks and resulted in acceptable sensitivity and specificity with an area under the ROC curve of 77.5%. The third subnetwork was found to be a less specific building block (module) for describing SZ alterations. It projected a wider range of inter-individual variations and, therefore, had a lower chance to be considered as a SZ biomarker. These findings confirmed that investigating brain variations from a modular viewpoint can help to find subnetworks that are more sensitive to SZ-induced alterations. Altogether, our study results illustrated the developed method's ability to systematically find brain alterations caused by SZ disorder from a network perspective.

Copy Number Variations and Schizophrenia

Schizophrenia is a neurodevelopmental disorder with genetic and environmental factors involved in its aetiology. Genetic liability contributing to the development of schizophrenia is a subject of extensive research activity, as reliable data regarding its aetiology would enable the improvement of its therapy and the development of new methods of treatment. A multitude of studies in this field focus on genetic variants, such as copy number variations (CNVs) or single-nucleotide variants (SNVs). Certain genetic disorders caused by CNVs including 22q11.2 microdeletion syndrome, Burnside-Butler syndrome (15q11.2 BP1-BP2 microdeletion) or 1q21.1 microduplication/microdeletion syndrome are associated with a higher risk of developing schizophrenia. In this article, we provide a unifying framework linking these CNVs and their associated genetic disorders with schizophrenia and its various neural and behavioural abnormalities.

Personality traits and perceived cognitive function in lebanese healthcare professionals

BACKGROUND

The healthcare field, a well-known field associated with variety of stressors, leaves healthcare professionals at an increased risk of both physical and mental problems. COVID-19 pandemic has recently been added to the stressful factors by endangering further the cognitive function of healthcare workers. On another hand, personality traits have been shown to have pervasive associations with functioning across various cognitive domains. Thus, this study aims to evaluate association between personality traits and perceived cognitive function among healthcare professionals in Lebanon during the collapsing period (following the severe economic crisis and the COVID-19 pandemic).

METHODS

This cross-sectional study was conducted between November 2021 and January 2022 enrolled 406 Lebanese participants using the convenience sampling technique for data collection. Healthcare professionals from all specialties who received the online link to the survey were eligible to participate. The Big Five Inventory-2 (BFI-2) and Fact Cog scale were used to assess personality traits and cognitive function.

RESULTS

After adjustment over all variables (age, gender, household crowding index, physical activity index, marital status, profession and the other four personality traits), higher negative emotionality was significantly associated with a worse cognitive function, whereas more extroversion and conscientiousness were significantly associated with a better cognitive function.

CONCLUSION

Our study adds to the narrow body of research revolving around the relationship between personality traits and perceived cognitive function in Lebanese healthcare professionals during these hard times in Lebanon. These results show that the choice of these cognitive processes is strongly affected by different personality traits, such as extroversion, conscientiousness, and negative emotionality. This study encourages the need to conduct further research that assess the changes in cognition in life stressors along with personality traits.

A Systematic Review of Intermittent Theta Burst Stimulation for Neurocognitive Dysfunction in Older Adults with Schizophrenia

OBJECTIVE

Neurocognitive dysfunction is thought to be one of the core clinical features of schizophrenia, and older adults with schizophrenia exhibited greater overall cognitive deficits than younger adults. The aim of this systematic review was to examine the neurocognitive effects of intermittent theta burst stimulation (iTBS) as an adjunctive treatment for older adults suffering from schizophrenia.

METHODS

Randomized double-blinded controlled trials (RCTs) investigating the neurocognitive effects of adjunctive active iTBS versus sham iTBS in older adults with schizophrenia were systematically identified by independent investigators searching Chinese and English databases.

RESULTS

Two double-blinded RCTs (n = 132) compared the neurocognitive effects of adjunctive active iTBS (n = 66) versus sham iTBS (n = 66) in patients that fulfilled the inclusion criteria of this systematic review and were analyzed. One RCT found significant superiority of active iTBS over sham iTBS in improving neurocognitive performance in older adults with schizophrenia. In the other RCT, the findings on the neurocognitive effects of iTBS as measured by three different measurement tools were inconsistent. The dropout rate was reported in the two RCTs, ranging from 3.8% (3/80) to 7.7% (4/52).

CONCLUSION

There is preliminary evidence that adjunctive iTBS may have some beneficial effects in the treatment of neurocognitive function in older patients with schizophrenia. Future RCTs with larger sample sizes focusing on the neurocognitive effects of adjunctive iTBS in older adults with schizophrenia are warranted to verify these findings.

A comparative study of cognitive functions between schizophrenia and obsessive-compulsive disorder

Background

Schizophrenia (SZ) and obsessive-compulsive disorder (OCD) are closely linked, have a high comorbidity rate, and their differential diagnosis is challenging in clinic. Some studies have found common cognitive deficits in some domains between them. The goal of this research was to compare the cognitive functions of SZ and OCD in order to offer a clinical foundation for differential diagnosis and treatment of the two disorders.

Methods

A control design was used in this study, which comprised 61 patients with SZ, 60 individuals with OCD, and 51 healthy controls (HC). We assessed patients' cognitive functions by testing six domains, including visual learning, reasoning and problem solving, verbal learning, attention/vigilance, speed of processing and working memory.

Results

The results showed that patients with SZ had cognitive impairments in all areas except attention/vigilance, while patients with OCD only had cognitive impairment in reasoning and problem-solving. Overall, patients with SZ did not perform as well as patients with OCD in all domains.

Conclusions

In terms of neurocognition, both of SZ and OCD patients have defects in reasoning and problem solving. In addition to this, SZ patients also performed worse than HC in other areas such as speed of processing, working memory, verbal learning and visual learning. On the overall level, cognitive performance is better in OCD patients than in SZ patients. The field of reasoning and problem solving can be used as a new goal to study the relationship and treatment strategies between them in the future.

Aberrant hippocampus and amygdala morphology associated with cognitive deficits in schizophrenia

Background

Working memory deficits are thought to be a primary disturbance in schizophrenia. We aimed to identify differences in morphology of the hippocampus and amygdala in patients with schizophrenia compared with healthy controls (HCs), and in patients who were either neuropsychologically near normal (NPNN) or neuropsychologically impaired (NPI). Morphological disturbances in the same subfields of the hippocampus and amygdala, but of greater magnitude in those with NPI, would strengthen evidence for the centrality of these limbic regions and working memory deficits in the pathogenesis of schizophrenia.

Methods

We acquired anatomical MRIs in 69 patients with schizophrenia (18 NPNN, 46 NPI) and 63 age-matched HC participants. We compared groups in hippocampus and amygdala surface morphologies and correlated morphological measures with clinical symptoms and working memory scores.

Results

Schizophrenia was associated with inward deformations of the head and tail of the hippocampus, protrusion of the hippocampal body, and widespread inward deformations of the amygdala. In the same regions where we detected the effects of schizophrenia, morphological measures correlated positively with the severity of symptoms and inversely with working memory performance. Patients with NPI displayed a similar pattern of anatomical abnormality compared to patients with NPNN.

Conclusion

Our findings indicate that anatomical abnormalities of the hippocampus relate to working memory performance and clinical symptoms in persons with schizophrenia. Moreover, NPNN and NPI patients may lie on a continuum of severity, both in terms of working memory abilities and altered brain structure, with NPI patients being more severe than NPNN patients in both domains.

Examining the association of life course neurocognitive ability with real-world functioning in schizophrenia-spectrum disorders

There is considerable variability in neurocognitive functioning within schizophrenia-spectrum disorders, and neurocognitive performance ranges from severe global impairment to normative performance. Few investigations of neurocognitive clusters have considered the degree to which deterioration relative to premorbid neurocognitive abilities is related to key illness characteristics. Moreover, while neurocognition and community functioning are strongly related, understanding of the sources of variability in the association between these two domains is also limited; it is unknown what proportion of participants would over-perform or under-perform the level of functioning expected based on current neurocognitive performance vs. lifelong attainment. This study examined data from 954 outpatients with schizophrenia-spectrum disorders across three previous studies. Neurocognition, community functioning, and symptoms were assessed. Neurocognitive subgroups were created based on current neurocognition, estimated premorbid IQ, and degree of deterioration from premorbid using z-score cut-offs; functional subgroups were created with cluster analysis based on the Specific Level of Functioning Scale and current neurocognition. The sample was neurocognitively heterogeneous; 65% displayed current neurocognitive impairment and 84% experienced some level of deterioration. Thirty percent of our sample was relatively higher functioning despite significant neurocognitive impairment. Individuals with better community functioning, regardless of neurocognitive performance, had lower symptom severity compared to those with worse functioning. These results highlight the variability in neurocognition and its role in functioning. Understanding individual differences in neurocognitive and functional profiles and the interaction between prior and current cognitive functioning can guide individualized treatment and selection of participants for clinical treatment studies.

Pharmacological interventions for social cognitive impairments in schizophrenia: A protocol for a systematic review and network meta-analysis

Background

Social cognitive impairments adversely affect social functioning (e.g., employment status) in patients with schizophrenia. Although pharmacological interventions have been suggested to provide some benefits on social cognition, little information is available on the comparative efficacy of pharmacotherapy. Thus, the aim of this planned systematic review and network meta-analysis is to perform a quantitative comparison of the effects of various psychotropic drugs, including supplements, on social cognition disturbances of schizophrenia.

Methods

The literature search will be carried out using the PubMed, Embase, Cochrane Central Register of Controlled Trials, PsycINFO, ClinicalTrials.gov, and International Clinical Trials Registry Platform databases from inception onward. Randomized controlled trials that examined the efficacy of drugs in social cognitive disturbances will be included, based on the most recent studies and the broader literature than previously searched. This protocol defines a priori the methods that will be used for study selection, data collection, quality assessment, and statistical syntheses.

Discussion

The findings this work are expected to help promote the development of better therapeutics of social cognitive impairments in schizophrenia and related psychiatric conditions.

Systematic Review Registration

[www.crd.york.ac.uk/prospero], identifier [CRD42021293224].

Cluster analysis of negative symptoms identifies distinct negative symptom subgroups

The heterogeneity of schizophrenia has been acknowledged for decades because of the diverse presentation of symptoms, illness course, and treatment response noted between individuals diagnosed with the disorder. Cluster analysis has been used as a statistical method to determine whether schizophrenia subgroups might be identified based on symptom heterogeneity. However, there is very limited research examining whether heterogeneity in negative symptoms might be useful in establishing schizophrenia subtypes, particularly research examining newer models of negative symptoms based on five latent constructs including anhedonia, asociality, avolition, blunted affect, and alogia. The Brief Negative Symptom Scale was used to assess the five negative symptoms domains in a sample of 220 outpatients diagnosed with schizophrenia or schizoaffective disorder. Cluster analysis supported a four-cluster solution, comprising clusters of subjects with low negative symptoms (LNS), severe negative symptoms (SNS), and two clusters with moderate negative symptoms, one with predominantly elevated blunted affect (BA) and one with elevated avolition (AV). The LNS, SNS, BA, and AV clusters significantly differed on external validators including clinical characteristics, neurocognition, and functional outcome. Findings suggest that schizophrenia heterogeneity can be parsed according to negative symptom subtypes that have distinct clinical and neuropsychological profiles. Implications for diagnosis and treatment are discussed.

Rethinking delusions: A selective review of delusion research through a computational lens

Delusions are rigid beliefs held with high certainty despite contradictory evidence. Notwithstanding decades of research, we still have a limited understanding of the computational and neurobiological alterations giving rise to delusions. In this review, we highlight a selection of recent work in computational psychiatry aimed at developing quantitative models of inference and its alterations, with the goal of providing an explanatory account for the form of delusional beliefs in psychosis. First, we assess and evaluate the experimental paradigms most often used to study inferential alterations in delusions. Based on our review of the literature and theoretical considerations, we contend that classic draws-to-decision paradigms are not well-suited to isolate inferential processes, further arguing that the commonly cited 'jumping-to-conclusion' bias may reflect neither delusion-specific nor inferential alterations. Second, we discuss several enhancements to standard paradigms that show promise in more effectively isolating inferential processes and delusion-related alterations therein. We further draw on our recent work to build an argument for a specific failure mode for delusions consisting of prior overweighting in high-level causal inferences about partially observable hidden states. Finally, we assess plausible neurobiological implementations for this candidate failure mode of delusional beliefs and outline promising future directions in this area.

Lifespan evolution of neurocognitive impairment in schizophrenia - A narrative review

Cognitive impairment is a well-recognized key feature of schizophrenia. Here we review the evidence on (1) the onset and sensitive periods of change in cognitive impairment before and after the first psychotic episode, and (2) heterogeneity in neurocognitive presentations across cognitive domains between and within individuals. Overall, studies suggest that mild cognitive impairment in individuals who develop schizophrenia or related disorders is already present during early childhood. Cross-sectional studies further suggest increasing cognitive impairments from pre- to post-psychosis onset, with the greatest declines between adolescence, the prodrome, and the first psychotic episode and with some variability between domains. Longitudinal studies with more than 10 years of observation time are scarce but support mild cognitive declines after psychosis onset until late adulthood. Whether and how much this cognitive decline exceeds normal aging, proceeds further in older patients, and is specific to certain cognitive domains and subpopulations of patients remains to be investigated. Finally, studies show substantial heterogeneity in cognitive performance in schizophrenia and suggest a variety of impairment profiles.

This review highlights a clear need for long-term studies that include a control group and individuals from adolescence to old age to better understand critical windows of cognitive change and their predictors. The available evidence stresses the importance of interventions that aim to counter cognitive decline during the prodromal years, as well as careful assessment of cognition in order to determine who will profit most from which cognitive training.

Impact of Nicotine on Cognition in Patients With Schizophrenia: A Narrative Review

Nicotine is the psychoactive component given tobacco has several main components and acts as an agonist for nicotinic acetylcholine receptors (nAChRs) in the nervous system. Although the ligand-gated cation channels known as nAChRs are found throughout the nervous system and body, this review focuses on neuronal nAChRs. Individuals with psychiatric diseases such as schizophrenia, comorbid substance use disorders, attention-deficit hyperactivity disorder, major depression, and bipolar disorder have increased rates of smoking. These psychiatric disorders are associated with various cognitive deficits, including working memory, deficits in attention, and response inhibition functions. The cognitive-enhancing effects of nicotine may be particularly relevant predictors of smoking initiation and continuation in this comorbid population. Individuals with schizophrenia make up a significant proportion of smokers. Literature suggests that patients smoke to alleviate cognitive deficiencies due to the stimulating effects of nicotine. This narrative review examines the role of nicotine on cognition in schizophrenia.

Are Patients with Schizophrenia Reliably Reporting their Cannabis Use? An African Cross-sectional Study

BACKGROUND

Most studies of the prevalence of cannabis use among patients with schizophrenia used a self-report as declared by the patient himself. We hypothesize that patients with schizophrenia did not tell the truth and might underreport their use for many reasons to be discussed later. Indeed, the under-report of cannabis use among these patients can affect the effectiveness of their treatment.

AIMS

To assess the degree of agreement between the prevalence values obtained from patients' reports and the results of the toxicological tests.

METHODS

A cross-sectional study was carried out on 403 patients with schizophrenia. A sociodemographic, psychiatric history and illicit drug use profile was performed for each patient. We assessed the patients with the Positive and Negative Syndrome Scale (PANSS), Calgary Depression score (CDSS), Barratt Impulsiveness Score (BIS-10) and Medication Adherence Rating Scale (MARS). The consumption of cannabis used was confirmed with MINI International Neuropsychiatric Interview (MINI-DSM IV) and using toxicological analysis.

RESULTS

Among the 403 patients who consented to give their urine samples, 49.1% (198/403) tested positive for cannabis, and 41.41% (82/198) underreported their use. The sensitivity and specificity of the questionnaire were 0.58 and 0.74. Based on the comparison between sociodemographic and psychiatric history data of patients who self-report and underreport their cannabis use, no significant difference was observed except for the duration of cannabis use and the score on the medication adherence scale. Moreover, it was found that impulsivity, PANSS score, CDSS score, and the type of schizophrenia are not involved in predicting the underreporting of cannabis use.

CONCLUSION

The rate of patients who under-report cannabis use is important. Therefore, toxicological analysis is becoming relevant for identifying drug use among schizophrenic patients and in the addictive comorbidity research field.

Social cognition, neurocognition, symptomatology, functional competences and outcomes in people with schizophrenia - A network analysis perspective

BACKGROUND

Extensive difficulties in reaching functional milestones characterize schizophrenia and related psychotic disorders. These impairments are in part explained by lower social cognitive abilities, cognitive impairment, and current psychopathology. The present study aims to model dynamic associations among social cognition, neurocognition, psychopathology, social skills, functional capacity, and functional outcomes in schizophrenia using network analysis in order to identify those factors that are most central to functioning.

METHODS

The sample consisted of 408 patients with schizophrenia spectrum disorders who were drawn from the SCOPE project. Participants completed a complex battery of state-of-the-art measures of social cognition, neurocognition, and functional outcomes. Gaussian Graphical Modeling was used for estimation of the network structure. Accuracy of the network was evaluated using the Bootstrap method.

RESULTS

Data supported the importance of functional capacity and social skills, which are prerequisites to real - world outcomes. These variables were among the most central in the network. Social cognition was related to functional capacity, social skills, and real - world functioning. Negative symptoms were connected to functional capacity, social skills, and real - world functioning.

CONCLUSIONS

Predictors of functional outcomes are complexly associated with each other. Functional capacity, social - skills, working memory, negative symptoms, mentalizing, and emotion recognition were central nodes that support their importance as potential targets of personalized intervention.

The central executive network and executive function in healthy and persons with schizophrenia groups: a meta-analysis of structural and functional MRI

This meta-analysis evaluated the extent to which executive function can be understood with structural and functional magnetic resonance imaging. Studies included structural in schizophrenia (k = 8; n = 241) and healthy controls (k = 12; n = 1660), and functional in schizophrenia (k = 4; n = 104) and healthy controls (k = 12; n = 712). Results revealed a positive association in the brain behavior relationship when pooled across schizophrenia and control samples for structural (pr = 0.27) and functional (pr = 0.29) modalities. Subgroup analyses revealed no significant difference for functional neuroimaging (pr = .43, 95%CI = -.08-.77, p = .088) but with structural neuroimaging (pr = .37, 95%CI = -.08-.69, p = .015) the association to executive functions is lower in the control group. Subgroup analyses also revealed no significant differences in the strength of the brain-behavior relationship in the schizophrenia group (pr = .59, 95%CI = .58-.61, p = .881) or the control group (pr = 0.19, 95%CI = 0.18-0.19, p = 0.920), suggesting concordance.

Characterising Demographic, Clinical and Functional Features of Cognitive Subgroups in Schizophrenia Spectrum Disorders: A Systematic Review

Considerable cognitive heterogeneity is present within the schizophrenia spectrum disorder (SSD) population. Several subgroups characterised by more homogenous cognitive profiles have been identified. It is not yet clear however, whether these subgroups represent different points along a continuum of cognitive symptom severity, or whether they reflect unique profiles of the disorder. One way to determine this is by comparing subgroups on their non-cognitive characteristics. The aim of the present review was to systematically summarise our current understanding of the non-cognitive features of the cognitive subgroups of schizophrenia spectrum disorder (SSD). Thirty-five relevant studies were identified from January 1980 to March 2020. Cognitive subgroups were consistently compared on age, sex, education, age of illness onset, illness duration, positive, negative and disorganised symptoms, depression and psychosocial functioning. It was revealed that subgroups were consistently distinguished by education, negative symptom severity and degree of functional impairment; with subgroups characterised by worse cognitive functioning performing/rated worse on these characteristics. The lack of consistent subgroup differences for the majority of the non-cognitive characteristics provides partial support for the notion that cognitive subgrouping in SSD is not simply reflecting a rehash of previously identified clinical subtypes. However, as subgroups were consistently distinguished by three characteristics known to be associated with cognition, our understanding of the extent to which the cognitive subgrouping approach is representing separate subtypes versus subdivisions along a continuum of symptom severity is still not definitive.

Cognitive decline and impairment in schizophrenia spectrum disorders reconsidered

BACKGROUND

This study applied an algorithm developed to identify schizophrenia spectrum disorder patients with probable decrements between estimated premorbid and current cognitive ability (Keefe et al., 2005). Cognitive trajectories and associated functional status were examined in patients and control participants.

METHODS

Patients with schizophrenia or schizoaffective disorder (n = 139) and control participants (n = 63) completed measures of verbal and working memory, processing speed, verbal fluency, reading ability and non-verbal reasoning. A predicted cognitive composite score was generated using control participants' parental education and reading scores, consistent with methods in Keefe et al. (2005), and compared to current performance. Three performance trajectory profiles were identified: decrement, stable, and increment. Functionality and clinical status were assessed with the Multidimensional Scale of Independent Functioning (MSIF) and the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Approximately 60% (n = 83) of patients demonstrated a decrement trajectory, 16% (n = 22) demonstrated an increment trajectory, and 24% (n = 34) demonstrated a stable trajectory. Patients with decrement profiles were significantly more symptomatic (negative) and functionally impaired (MSIF) than those with increment profiles. Patients with increment and normal-range performance profiles remained functionally deficient relative to controls.

CONCLUSIONS

Schizophrenia and schizoaffective patients meeting psychometric criteria for cognitive decline relative to estimated premorbid levels are common in the outpatient population but may occur less frequently than earlier estimates suggest. Minorities with stable and improved performance profiles also exist, show clinical and functional advantage relative to more typical patients, but underperform healthy controls.

Impairment of Executive Functions Associated With Lower D-Serine Serum Levels in Patients With Schizophrenia

A core symptom that is frequently linked with dysregulation of glutamatergic neurotransmission in regard to schizophrenia is impairment or damage of executive functioning as a component of cognitive deficiency. The amino acid D-serine plays the role of an endogenous coagonist at the glutamatergic N-methyl-D-aspartate (NMDA) receptor glycine modulatory site. Considerably reduced serum levels of D-serine were found in patients suffering from schizophrenia compared with healthy control participants. An increase in D-serine led to augmented cognitive functionality in patients suffering from schizophrenia who were undergoing clinical trials and given the treatment of first- and second-generation antipsychotics. The study proposed the hypothesis that the D-serine blood serum levels may be linked with the extent of executive functionality in those suffering from the mental illness in question. For the purpose of examining executive function in such patients, the Rey-Osterrieth Complex Figure, Trail Making, and Wisconsin Card Sorting tests were applied (n = 50). High-performance liquid chromatography was used to gauge the total serine and D-serine levels. The extent of damage was examined through neuropsychological tests and was found to be considerably linked to D-serine serum level and the D-serine/total serine ratio (p < 0.05) in the sample being considered. A lower average serum level of D-serine and lower D-serine/total serine ratio were observed in participants with the worst performance compared with those displaying the best performance-this was true when the patients were split into quartile groups based on their results (p < 0.05). The findings of modified D-serine serum levels and the D-serine/total serine ratio linked to the extent of damage in executive functioning indicate that serine metabolism that is coresponsible for NMDA receptor dysfunction has been changed.

Does Yoga Have a Role in Schizophrenia Management?

PURPOSE OF REVIEW

To review the efficacy of add-on yoga therapy in improving symptoms of schizophrenia and quality of life and examine the possible underlying biological mechanisms of yoga in schizophrenia.

RECENT FINDINGS

Quality of life, cognitive symptoms, and negative symptoms have been found to improve with add-on yoga therapy in schizophrenia (pooled mean effect size 0.8, 0.6, and 0.4, respectively). Yoga also seems to have a small effect on improving positive symptoms. Less explored areas include adverse effects of yoga itself as well as its effects on antipsychotic-induced complications. Preliminary findings suggest that the effects of yoga may be mediated by neurohormonal mechanisms and functional changes in brain activity. Add-on yoga therapy is a potential treatment option for improving quality of life, cognitive symptoms, and negative symptoms in schizophrenia. Future studies should explore efficacy in multicentric trials as well as possible neurobiological changes underlying the effects.

α7 nicotinic receptor agonist and positive allosteric modulators differently improved schizophrenia-like cognitive deficits in male rats

The majority of schizophrenia patients have cognitive deficits as a separate symptom cluster independent of positive or negative symptoms. Current medicines, unfortunately, cannot provide clear benefits for cognitive symptoms in patients. Recent findings showed decreased α7 nicotinic acetylcholine receptor (nAChR) expressions in subjects with schizophrenia. α7 nAChR full/partial agonists and positive allosteric modulators (PAMs) may be valuable drug candidates to treat cognitive deficits of disease. This study comparatively investigated the effect of α7 nAChR agonist (A-582941), type I PAM (CCMI), type II PAM (PNU-120596), and the antipsychotic drug (clozapine) on behavioral, molecular, and immunohistochemical parameters in a subchronic MK-801 model of schizophrenia in male rats. Novel object recognition (NOR) and Morris water maze (MWM) tests were performed to evaluate recognition and spatial memories, respectively. Gene and protein expressions of parvalbumin, glutamic acid decarboxylase-67 (GAD67), and α7 nAChR were examined in the rats' hippocampal tissue. The subchronic MK-801 administration produced cognitive deficits in the NOR and MWM tests. It also decreased the protein and gene expressions of parvalbumin, GAD67, and α7 nAChR in the hippocampus. Clozapine, A-582941, and PNU-120596 but not CCMI increased the parvalbumin and α7 nAChR expressions and provided benefits in recognition memory. Interestingly, clozapine and CCMI restored the MK-801 induced deficits on GAD1 expression and spatial memory while A-582941 and PNU-120596 were ineffective. These results indicated that α7 nAChR agonist, type I and type II PAMs may provide benefits in different types of cognitive deficits rather than a complete treatment in schizophrenia.

Differences in executive function among patients with schizophrenia, their unaffected first-degree relatives and healthy participants

BACKGROUND

Patients with schizophrenia (SCZ) display impaired executive functions compared with healthy controls (HCs). Furthermore, unaffected first-degree relatives (FRs) of patients with SCZ independently perform worse executive functions than do HCs. However, few studies have investigated the differences in executive functions assessed among patients with SCZ, FRs, and HCs, and the findings are inconsistent.

METHODS

We investigated diagnostic differences in executive functions, namely, (i) numbers of categories achieved (CA), (ii) total errors (TE) and (iii) %perseverative errors of Nelson types (%PEN), using the Wisconsin card sorting test (WCST) among patients with SCZ (n=116), unaffected FRs (n=62) and HCs (n=146) at a single institute. Correlations between these executive functions and clinical variables were investigated.

RESULTS

Significant differences existed in all executive functions among diagnostic groups (CA, F2,319=15.5, p=3.71×10-7; TE, F2,319=16.2, p=2.06×10-7; and %PEN, F2,319=21.3, p=2.15×10-9). Patients with SCZ had fewer CA and more TE and %PEN than those of HCs (CA, Cohen's d=-0.70, p=5.49×10-8; TE, d=0.70, p=5.62×10-8; and %PEN, d=0.82, p=2.85×10-10) and FRs (TE, d=0.46, p=3.73×10-3 and %PEN, d=0.38, p=0.017). Of the three executive functions, CA and %PEN of FRs were intermediately impaired between patients with SCZ and HCs (CA, d=-0.41, p=0.011 and %PEN, d=0.41, p=0.012). In contrast, no significant difference in TE existed between FRs and HCs (d=0.22, p=0.18). Although CA and TE were affected by the duration of illness (p<0.017), %PEN was not affected by any clinical variable in patients with SCZ (p>0.017).

CONCLUSIONS

Executive function, particularly %PEN, could be a useful intermediate phenotype for understanding the genetic mechanisms implicated in SCZ pathophysiology.

Correlation between Performance-Based and Interview-Based Cognitive Measurements in Patients with Schizophrenia

OBJECTIVE

The Measurement and Treatment Research to improve Cognition in Schizophrenia Consensus Cognitive Battery (MCCB) is used to measure the cognitive function of patients with schizophrenia. In some situations, interview-based measures such as the Schizophrenia Cognition Rating Scale (SCoRS) may be appropriate. In this study, we analyzed the correlation between performance- and interview-based measurements in patients with schizophrenia.

METHODS

Fifty-six clinically stable patients were recruited. To evaluate cognitive function, we used the MCCB performance-based measure and the SCoRS interview-based measure. Measurements were taken at baseline, and 2 weeks and 3 months later. Spearman correlations were computed between each SCoRS item's interviewer rating and each MCCB score.

RESULTS

The correlation between the MCCB overall T score and the SCoRS global score was the strongest (r=-0.52), while the SCoRS total score and the MCCB Speed of Processing score also correlated (r=-0.48). The SCoRS global score showed statistically significant correlations with all seven MCCB domains and the overall T score.

CONCLUSION

This study reveals correlations between MCCB domains and SCoRS items. Since we find that interview-based measurements are highly correlated with performance-based measurements, we suggest them as a useful cognitive function evaluation tool that can easily be applied in clinical settings.

Emerging 5-HT receptor antagonists for the treatment of Schizophrenia

INTRODUCTION

While antipsychotics have been generally successful in treating psychosis in schizophrenia, there is a major treatment gap for negative symptoms and cognitive deficits. Given that these aspects of the disease contribute to poor functional outcomes independently of positive symptoms, treatments would have profound implications for quality of life. The 5-HT_2A- receptor has been considered a potential target for interventions aimed at negative and cognitive symptoms and multiple antagonists and inverse agonists of this receptor have been tested.

AREAS COVERED

Ritanserin and volinanserin, are historically important compounds in this area, while pimavanserin, roluperidone, and lumateperone are either newly approved, in late stages of development, or currently being tested for efficacy in schizophrenia-related features. The focus will be on their efficacy in the treatment of negative symptoms, with a limited secondary discussion of cognition.

EXPERT OPINION

In addition to their efficacy in treating negative symptoms and cognition, these compounds may also have a role in modulating antipsychotic-induced dopamine super-sensitivity and preventing relapse. They may also show efficacy in treating patients with milder symptoms such as patients with schizotypal personality disorder and attenuated psychosis syndrome. Their utility may also expand outside the spectrum of schizophrenia to encompass Parkinson's Disease psychosis, major depression, bipolar depression, and dementia-associated apathy.

Functional network connectivity in early-stage schizophrenia

Schizophrenia is a disorder of altered neural connections resulting in impaired information integration. Whole brain assessment of within- and between-network connections may determine how information processing is disrupted in schizophrenia. Patients with early-stage schizophrenia (n = 56) and a matched control sample (n = 32) underwent resting-state fMRI scans. Gray matter regions were organized into nine distinct functional networks. Functional connectivity was calculated between 278 gray matter regions for each subject. Network connectivity properties were defined by the mean and variance of correlations of all regions. Whole-brain network measures of global efficiency (reflecting overall interconnectedness) and locations of hubs (key regions for communication) were also determined. The control sample had greater connectivity between the following network pairs: somatomotor-limbic, somatomotor-default mode, dorsal attention-default mode, ventral attention-limbic, and ventral attention-default mode. The patient sample had greater variance in interactions between ventral attention network and other functional networks. Illness duration was associated with overall increases in the variability of network connections. The control group had higher global efficiency and more hubs in the cerebellum network, while patient group hubs were more common in visual, frontoparietal, or subcortical networks. Thus, reduced functional connectivity in patients was largely present between distinct networks, rather than within-networks. The implications of these findings for the pathophysiology of schizophrenia are discussed.

Cognitive and clinical predictors of community functioning across the psychoses

Schizophrenia, bipolar disorder, and related psychotic illnesses are common, serious mental disorders that are often associated with functional impairments and poor quality of life, even after clinical recovery. Cognitive dysfunction is a strong predictor of functional impairment; however, findings regarding relative impairments in functioning and cognition across diagnoses have been mixed, as have reports of the contribution of clinical symptoms and other illness features to functioning across diagnostic boundaries. We assessed 211 patients with psychotic disorders and 87 healthy controls using the MATRICS Consensus Cognitive Battery, clinical measures of state mood and psychotic symptoms, and an interview measure of community functioning. Diagnostic groups were compared on MATRICS composite and domain scores, and clinical and functional measures. We then examined cognitive, clinical, and demographic predictors of community functioning using stepwise hierarchical linear regression. All three patient groups exhibited deficits in most cognitive domains relative to controls, and significantly poorer community functioning. While scores on most cognitive domains did not differ by diagnosis, when groups did differ patients with schizophrenia performed worse than patients with bipolar disorder. Cognition was correlated with functioning across the sample. The final regression model included negative symptoms, mania, social cognition, and processing speed, and explained 47% of the variance in community functioning scores across patient groups. Residual negative symptoms, residual mania, and social cognition significantly and independently predicted community functioning. These findings indicate that, while all cognitive domains are associated with community outcomes, when considered together and with clinical symptoms, negative symptoms, mania, and social cognition are the strongest predictors across diagnoses. Development of interventions targeting negative symptoms and social cognition may be effective in improving community functioning for patients across diagnoses.

Improving Cognition via Exercise (ICE): Study Protocol for a Multi-Site, Parallel-Group, Single-Blind, Randomized Clinical Trial Examining the Efficacy of Aerobic Exercise to Improve Neurocognition, Daily Functioning, and Biomarkers of Cognitive Change in Individuals with Schizophrenia

Individuals with schizophrenia (SZ) display cognitive deficits that have been identified as major determinants of poor functioning and disability, representing a serious public health concern and an important target for interventions. At present, available treatments offer only minimal to moderate benefits to ameliorate cognitive deficits. Thus, there remains an urgent need to identify novel interventions to improve cognition in people with SZ. Emerging evidence from animal and basic human research suggests aerobic exercise training (AE) has beneficial effects on cognition. Preliminary findings suggest that AE is efficacious in improving cognitive functioning in SZ, however the extant studies have been limited by small samples, a dearth of information on biologically-relevant covariates, and limited information on impact on daily functioning. Additionally, while AE-related cognitive benefits have been linked to Brain-Derived Neurotrophic Factor (BDNF) upregulation, this putative mechanism needs confirmation. The present report describes a study protocol designed to address these limitations-we review and summarize the current literature on treatment of cognitive deficits in SZ, state the rationale for employing AE to target these deficits, and describe the current protocol-a multi-site, single-blind, randomized clinical trial aiming to recruit 200 community-dwelling individuals with SZ. Participants are randomized to one of two 12-week interventions: AE using active-play video games (i.e., Xbox Kinect) and traditional cardiovascular exercise equipment or a stretching-and-toning (ST) control intervention. Participants undergo assessments of aerobic fitness, cognition, and daily functioning, as well as BDNF and other biomarkers of cognitive change, at baseline and after 6-and 12-weeks.

The emerging pattern of shared polygenic architecture of psychiatric disorders, conceptual and methodological challenges

Genome-wide association studies have transformed psychiatric genetics and provided novel insights into the genetic etiology of psychiatric disorders. Two major discoveries have emerged; the disorders are polygenic, with a large number of common variants each with a small effect and many genetic variants influence more than one phenotype, suggesting shared genetic etiology. These concepts have the potential to revolutionize the current classification system with diagnostic categories and facilitate development of better treatments. However, to reach clinical impact, we need larger samples and better analytical tools, as most polygenic factors remain undetected. We here present statistical approaches designed to improve the yield of existing genome-wide association studies for polygenic phenotypes. We review how these tools have informed the current knowledge on the genetic architecture of psychiatric disorders, focusing on schizophrenia, bipolar disorder and major depression, and overlap with psychological and cognitive traits. We discuss application of statistical tools for stratification and prediction.

Characterising the structure of cognitive heterogeneity in schizophrenia spectrum disorders. A systematic review and narrative synthesis

The aim of the present review was to systematically summarise our current understanding of the structure of the cognitive heterogeneity that exists within schizophrenia spectrum disorder (SSD). Fifty-two relevant studies were identified from January 1980 to March 2019 that investigated cognitive subgroups within SSD. Twenty-five studies employed classification criteria based on current neuropsychological function, 14 studies employed various data-driven subgrouping methodologies and 13 studies investigated putative cognitive symptom trajectories. Despite considerable methodological variability, three distinct cognitive subgroups reliability emerged; a relatively intact cognitive subgroup characterised by high cognitive performance, an intermediate cognitive subgroup defined by mixed or moderate levels of cognitive function/dysfunction and a globally impaired subgroup characterised by severe cognitive deficits. Whilst preliminary evidence suggests that these subgroups may have further investigative relevance in and of themselves, additional research is required and discussed. A set of reporting guidelines are also presented to overcome the methodological inconsistencies identified in the reviewed literature.

Cognitive impairment in psychotic illness: prevalence, profile of impairment, developmental course, and treatment considerations

Despite effective pharmacological treatments for psychotic symptoms (eg, hallucinations, delusions), functional outcomes for people with psychotic disorders are often disappointing. Although it is not included in the diagnostic criteria for psychotic disorders, cognitive impairment is one of the strongest determinants of community functioning in this clinical population, and thus it is an important target for intervention. In this review, we discuss the major areas of research regarding impaired cognition in psychotic illness. The specific topics covered include: (i) the prevalence of cognitive impairment in psychotic disorders; (ii) the profile and magnitude of cognitive impairment in psychotic disorders; (iii) the developmental course of cognitive impairment; (iv) the longitudinal stability of cognitive impairment; and (v) treatment approaches to improve cognitive performance in people with psychotic disorders.
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Development and testing of a web-based battery to remotely assess cognitive health in individuals with schizophrenia

Cognitive impairment in schizophrenia is often severe, enduring, and contributes significantly to chronic disability. A standardized platform for identifying cognitive impairments and measuring treatment effects in cognition is a critical aspect of comprehensive evaluation and treatment for individuals with schizophrenia. In this project, we developed and tested a suite of ten web-based, neuroscience-informed cognitive assessments that are designed to enable the interpretation of specific deficits that could signal that an individual is experiencing cognitive difficulties. The assessment suite assays speed of processing, sustained attention, executive functioning, learning and socio-affective processing in the auditory and visual modalities. We have obtained data from 283 healthy individuals who were recruited online and 104 individuals with schizophrenia who also completed formal neuropsychological testing. Our data show that the assessments 1) are acceptable and tolerable to users, with successful completion in an average of under 40 min; 2) reliably measure the distinct theoretical cognitive constructs they were designed to assess; 3) can discriminate schizophrenia patients from healthy controls with a fair degree of accuracy (AUROC > 0.70); and 4) have promising construct, convergent, and external validity. Further optimization and validation work is in progress to finalize the evaluation process prior to promoting the dissemination of these assessments in real-world settings.

Comparison of prefrontal hemodynamic responses and cognitive deficits between adult patients with autism spectrum disorder and schizophrenia

Autism spectrum disorder (ASD) and schizophrenia share many phenotypic characteristics, but their association with prefrontal function have not been directly compared. The aim of this study is to compare cognitive profiles and their association with the prefrontal function between the two groups. We explored prefrontal dysfunction among adult individuals with ASD (n = 32), schizophrenia (n = 87), and healthy controls (HCs; n = 50). We assessed cognitive function in all participants using the Brief Assessment of Cognition in Schizophrenia (BACS). The BACS data of patients with schizophrenia were entered into hierarchical cluster analyses to assign subjects to a specific subgroup based on individual profiles. Using near-infrared spectroscopy, we measured hemodynamic responses in the fronto-temporal regions during a working memory task. Among the patients with schizophrenia, we defined 4 neurocognitive subgroups, including a global impairment, a mild impairment, and 2 selective impairment groups. Compared to the HCs, the ASD and schizophrenia groups had much weaker hemodynamic responses in the left DLPFC, left frontopolar cortex (FPC), and left inferior frontal gyrus. The ASD group showed a similar level of cognitive impairment with the mild level subgroup of schizophrenia. Additionally, the two groups shared reduced activity in the left DLPFC and left FPC during the task compared to HCs. Moreover, the BACS composite scores correlated positively with hemodynamic responses in a broad area involving fronto-temporal regions in the total patient sample. This research indicates considerable similarity in the left PFC dysfunction and its association with cognitive deficits between the disorders. These findings may guide future studies that investigate pathophysiological similarities between ASD and schizophrenia.

An examination of the moderating effects of neurophysiology on treatment outcomes from cognitive training in schizophrenia-spectrum disorders

BACKGROUND

Impairments in neurocognition and community functioning are core features of schizophrenia and cognitive training techniques have been developed with the aim of improving these impairments. While cognitive training has produced reliable improvements in neurocognition and functioning, little is known about factors that moderate treatment response. Electroencephalographic (EEG) measures provide a neurophysiological indicator of cognitive functions that may moderate treatment outcomes from cognitive training.

METHODS

Data from a clinical trial comparing two cognitive training approaches in schizophrenia-spectrum disorders were utilized in the current report. Cluster analysis was conducted to identify participant clusters based on baseline P300, mismatch negativity (MMN), and theta power during an n-back task, and the EEG measures were also examined as continuous predictors of treatment response.

RESULTS

Three clusters were identified based on the baseline EEG variables; however, there were no significant differences in treatment response across the three clusters. Higher P300 amplitude and theta power during the n-back at baseline were significantly associated with greater improvements in a cognitive composite score post-treatment. None of the EEG measures were significantly associated with treatment outcomes in specific cognitive domains or community functioning. Change in EEG measures from baseline to post-treatment was not significantly associated with durability of cognitive or functional change at 12-week follow-up.

CONCLUSIONS

Clusters derived from the EEG measures were not significantly associated with either neurocognitive or functional outcomes. P300 and n-back theta power may be associated with learning-related processes, which are important for acquisition and retention of skills during cognitive training programs. Future research should aim to identify at an individual level who is likely to respond to specific forms of cognitive enhancement.

Prevalence and determinants of cognitive impairment in the euthymic phase of bipolar disorders: results from the FACE-BD cohort

BACKGROUND

Cognitive deficits are a well-established feature of bipolar disorders (BD), even during periods of euthymia, but risk factors associated with cognitive deficits in euthymic BD are still poorly understood. We aimed to validate classification criteria for the identification of clinically significant cognitive impairment, based on psychometric properties, to estimate the prevalence of neuropsychological deficits in euthymic BD, and identify risk factors for cognitive deficits using a multivariate approach.

METHODS

We investigated neuropsychological performance in 476 euthymic patients with BD recruited via the French network of BD expert centres. We used a battery of tests, assessing five domains of cognition. Five criteria for the identification of neuropsychological impairment were tested based on their convergent and concurrent validity. Uni- and multivariate logistic regressions between cognitive impairment and several clinical and demographic variables were performed to identify risk factors for neuropsychological impairment in BD.

RESULTS

One cut-off had satisfactory psychometric properties and yielded a prevalence of 12.4% for cognitive deficits in euthymic BD. Antipsychotics use were associated with the presence of a cognitive deficit.

CONCLUSIONS

This is the first study to validate a criterion for clinically significant cognitive impairment in BD. We report a lower prevalence of cognitive impairment than previous studies, which may have overestimated its prevalence. Patients with euthymic BD and cognitive impairment may benefit from cognitive remediation.

Functional connectivity in distinct cognitive subtypes in psychosis

BACKGROUND

Cognitive dysfunction is common in psychotic disorders, and may reflect underlying pathophysiology. However, substantial cognitive heterogeneity exists both within and between diagnostic categories, creating challenges for studying the neurobiology of cognitive dysfunction in patients. The aim of this study was to identify patients with psychosis with intact versus impaired cognitive profiles, and to examine resting state functional connectivity between patient groups and compared to healthy controls to determine the extent to which patterns of connectivity are overlapping or distinct.

METHODS

Participants with affective or non-affective psychosis (n=120) and healthy controls (n=31) were administered the MATRICS Consensus Cognitive Battery, clinical and community functioning assessments, and an fMRI scan to measure resting state functional connectivity (RSFC). Cognitive composite scores were used to identify groups of patients with and without cognitive dysfunction. RSFC was compared between groups of patients and healthy controls, controlling for demographic and clinical variables.

RESULTS

Both cognitively intact and cognitively impaired patients showed decreased intrinsic connectivity compared to controls in frontoparietal control (FPN) and motor networks. Patients with cognitive impairment showed additional reductions in FPN connectivity compared to patients with intact cognition, particularly in subnetwork A.

CONCLUSIONS

We leveraged the heterogeneity in cognitive ability among patients with psychosis to disentangle the relative contributions of cognitive dysfunction and presence of an underlying psychotic illness using resting state functional connectivity. These findings suggest at least partially separable effects of presence of a psychotic disorder and neurocognitive impairment contributing to network dysconnectivity in psychosis.

Genome-wide analysis reveals extensive genetic overlap between schizophrenia, bipolar disorder, and intelligence

Schizophrenia (SCZ) and bipolar disorder (BD) are severe mental disorders associated with cognitive impairment, which is considered a major determinant of functional outcome. Despite this, the etiology of the cognitive impairment is poorly understood, and no satisfactory cognitive treatments exist. Increasing evidence indicates that genetic risk for SCZ may contribute to cognitive impairment, whereas the genetic relationship between BD and cognitive function remains unclear. Here, we combined large genome-wide association study data on SCZ (n = 82,315), BD (n = 51,710), and general intelligence (n = 269,867) to investigate overlap in common genetic variants using conditional false discovery rate (condFDR) analysis. We observed substantial genetic enrichment in both SCZ and BD conditional on associations with intelligence indicating polygenic overlap. Using condFDR analysis, we leveraged this enrichment to increase statistical power and identified 75 distinct genomic loci associated with both SCZ and intelligence, and 12 loci associated with both BD and intelligence at conjunctional FDR < 0.01. Among these loci, 20 are novel for SCZ, and four are novel for BD. Most SCZ risk alleles (61 of 75, 81%) were associated with poorer cognitive performance, whereas most BD risk alleles (9 of 12, 75%) were associated with better cognitive performance. A gene set analysis of the loci shared between SCZ and intelligence implicated biological processes related to neurodevelopment, synaptic integrity, and neurotransmission; the same analysis for BD was underpowered. Altogether, the study demonstrates that both SCZ and BD share genetic influences with intelligence, albeit in a different manner, providing new insights into their genetic architectures.

Executive Function Profiles in Pediatric Traumatic Brain Injury

Traumatic brain injury (TBI) results in heterogeneous patterns of neuropsychological impairment. This study investigated heterogeneity in executive function (EF) using the Comprehensive Trail Making Test (CTMT) to evaluate 121 children and adolescents with TBI and 121 matched normal controls. The TBI group performed approximately two standard deviations below controls. Cluster analyses indicated that a three-cluster solution best classified the TBI group and a four-cluster solution best classified controls. Greater impairment in EF was associated with lower intellectual, achievement, and neuropsychological test performance in the TBI group. Results suggest that EF deficits reflected in CTMT performance may be useful for classifying severity of TBI.

Current Status of Cognitive Remediation for Psychiatric Disorders: A Review

Cognition is an important factor that affects daily functioning and quality of life. Impairment in cognitive function is a common symptom present in various psychological disorders, which hinders patients from functioning normally. Given that cognitive impairment has devastating effects, enhancing this in patients should lead to improvements in compromised quality of life and functioning, including vocational functioning. Over the past 50 years, several attempts have been made to improve impaired cognition, and empirical evidence for cognitive remediation (CR) has accumulated that supports its efficacy for treating schizophrenia. More recently, CR has been successfully applied in the treatment of depressive disorders, bipolar disorders, attention deficit/hyperactivity disorder, and anorexia nervosa. This study critically reviews recent CR studies and suggests their future direction. This study aimed to provide a modern definition of CR, and examine the current status of empirical evidence and representative CR programs that are widely used around the world.

How can genetics help understand the relationship between cognitive dysfunction and schizophrenia?

Despite the consistent finding that cognitive dysfunction is a core characteristic of schizophrenia (SCZ), little is known about the underlying pathophysiology. Recent progress in human genetics, driven by large genome-wide association studies (GWAS), has provided new data about the genetic architecture of complex human traits, including cognition and SCZ. Novel analytical tools have provided unprecedented opportunities to leverage the large amount of information from GWAS. Here we review the latest findings related to genetic architecture and risk genes of SCZ and cognitive functions, and recent findings of overlapping genetic factors. The recent GWAS of SCZ implicate over 100 risk gene loci, each with a small effect. A similar genetic architecture seems to be present in cognitive domains, suggesting that these phenotypes are highly polygenic. Further, GWAS have revealed more than 20 gene loci associated with cognitive traits, including intelligence, general cognition (g-factor), reaction time and verbal-numerical reasoning. Several gene loci have been implicated in educational attainment, a proxy measure of cognitive function. Recently, overlapping gene loci were found between education and SCZ, and between SCZ and cognitive traits, suggesting common genetic risk between SCZ and cognitive dysfunction. Mathematical modeling of GWAS of cognition and SCZ indicate that only a fraction of the heritability is identified. The evidence suggests a polygenic architecture for SCZ and cognitive functions, and a large degree of shared genetic risk. This indicates novel molecular genetic mechanisms and strengthens the notion that SCZ is more likely a part of the normal distribution and not a separate entity.

Which levels of cognitive impairments and negative symptoms are related to functional deficits in schizophrenia?

BACKGROUND

Negative symptoms and cognitive impairments predict difficulties in aspects of everyday functioning in schizophrenia, with little research to date attempting to determine if there are threshold levels of impairment required to predict the severity of functional deficits.

METHODS

People diagnosed with chronic schizophrenia (n = 821) were assessed with the MCCB and PANSS, and rated by high contact informants with SLOF. Negative symptoms of reduced emotional experience were specifically targeted for analysis because of their previously identified relationships with social outcomes. We identified patients with moderate negative symptoms (at least one PANSS item ≥4) versus less severe symptoms (PANSS items ≤3) and divided patients on the basis of a single latent-trait global cognition score (neuropsychologically normal vs neuropsychologically impaired; performance at or below 1.0 SD from the normative population mean, T = 40), then examined correlations between cognition, negative symptoms and everyday functioning in the groups with lower and higher negative symptoms and those with/without cognitive impairment.

RESULTS

Even low levels of negative symptoms were correlated with ratings of social functioning. Cognitive performance in the neuropsychologically normal range, in contrast, was not correlated with any aspects of everyday functioning while more impaired performance predicted greater functional impairments.

CONCLUSIONS

Even minimal symptoms may be a target for clinical attention in the domains of negative symptoms, consistent with previous findings regarding social deficits in populations with modest negative symptoms (e.g., schizotypal personality disorder). Cognitive rehabilitation treatments might not improve social functioning if even low levels of negative symptoms (social amotivation) are present.

What genome-wide association studies reveal about the association between intelligence and mental health

Intelligence, as measured by standardised tests of cognitive function, such as IQ-type tests, is predictive of psychiatric diagnosis and psychological wellbeing. Using genome-wide association study (GWAS) data, a measure of the shared genetic effect across traits, can be quantified; because this can be done across samples, the confounding effects of psychiatric diagnosis do not influence the magnitude of these relationships. It is now known that there are genetic effects that act across intelligence and psychiatric diagnoses, which provide a partial explanation for the phenotypic link between intelligence and mental health. Potential causal effects between intelligence and mental health have been identified, and the regions of the genome responsible for some of these cross trait associations have begun to be characterised.