Factor structure of neurocognition and functional capacity in schizophrenia: a multidimensional examination of temporal stability

Dimensionality analysis of the German version of the Screen for Cognitive Impairment in Psychiatry (SCIP-G)

Background

Psychiatric disorders, especially schizophrenia, are characterised by cognitive impairment. The rapid detection of cognitive dysfunction - also in the course of the disease - is of great importance. The Screen for Cognitive Impairment in Psychiatry (SCIP) was developed to provide screening of psychiatric patients in clinical practice and is available in several languages. Prior psychometric investigations into the dimensionality of the SCIP have produced two different models: a one-factor model assumes that the five subscales of the SCIP load together, whereas an alternative model suggests that the subscales load on two factors, namely verbal memory and processing speed. We carried out a confirmatory factor analysis of the German version of the SCIP (SCIP-G).

Methods

323 patients with psychotic, bipolar affective, and depressive disorders were studied.

Results

The one-factor approach did not yield an acceptable model fit (chi-squared test: χ² = 109.5, df = 5, p < 0.001, χ²/df = 21.9). A two-factor solution, with the subtests Verbal Learning Test-Immediate Recall, Delayed Recall Test of the VLT, and Working Memory Test loading on the first factor, whereas the subtests Verbal Fluency Test and Psychomotor Speed Test loading on the second factor, obtained a good model fit (χ² = 6.7, df = 3, p = 0.08, χ²/df = 2.2).

Conclusions

These data show that a good model fit can be achieved with a two-factor solution for the SCIP. This study is the first to conduct a confirmatory factor analysis using the German SCIP version and to test its dimensional structure using a hypothesis-testing approach.

Multimodal Correlates of Cannabis Use among U.S. Veterans with Bipolar Disorder: An Integrated Study of Clinical, Cognitive, and Functional Outcomes

Objective: Cannabis use (CU) is common among persons with bipolar disorder (BD). Evidence suggests that CU is associated with poorer outcomes among persons with BD; however, these findings remain inconsistent. The present exploratory study aims to examine clinical, functional, and cognitive correlates of CU among persons with BD. Methods: U.S. veterans with BD type I who participated in a large-scale, nationwide study were categorized into four groups: current CU, past CU, past other drug use, and no drug use. Bivariate analyses, univariate analyses of covariance, and Levene's Test for Equality of Variance were used to compare groups on clinical, cognitive, and functional measures. Results: Of 254 (84.6% male) veterans with BD type I included in the analyses, 13 (5.1%) had current CU, 37 (14.5%) past CU, 77 (30.3%) past other drug use, and 127 (50%) reported no drug use. BD with CU was associated with post-traumatic stress disorder (PTSD) and experiencing lifetime suicidal ideation. Notably, current CU was associated with higher working memory performance, compared to both past CU and no drug use. Likewise, current CU was associated with higher functional capacity, compared to past CU as well as no drug use. Conclusions: These findings contribute to the growing literature on the complex effects of cannabis on BD. As the commercialization and legalization of cannabis increases, further research in this area is warranted to quantify posed risks to this population, and thereby guide clinical decision-making.

The relationship between cognition and functioning in schizophrenia: A semi-systematic review

In schizophrenia, impairments in neurocognition (NC) and social cognition (SC) are associated with reduced functional capacity (FC) and poor real-world functioning (RWF).

In this semi-systematic review, we examined this association across a range of research questions.

We conducted a systematic search in Embase and MEDLINE from 2005 to 2019, and conducted additional pragmatic searches. After screening of titles, abstracts and full-texts, we included 564 citations, of which 44 (26 primary studies, 15 systematic reviews and 3 narrative reviews) were prioritized for reporting.

Both NC and SC were significantly associated with functioning, with slightly stronger association for SC. Effect sizes were generally larger for FC than for RWF. NC showed stronger associations with occupational functioning and independent living, and SC with social functioning. Baseline cognition predicted long-term RWF up to 20 years of follow-up, though long-term data were limited for SC. Cognitive remediation improved RWF functioning, especially when it was combined with psychosocial rehabilitation.

SC mediated the relationship of NC with functioning. Negative symptoms appeared to mediate and moderate the association of cognition with functioning. Other factors involved included severity of cognitive dysfunction, metacognition, depression and choice of RWF instrument.

We discuss potential implications for studies of pharmacological cognitive interventions in schizophrenia – the relevance of both NC and SC, the advantage of adjunctive psychosocial rehabilitation, the role of relevant moderating and mediating variables, and the challenges with RWF instrument selection. Successful cognitive interventions could allow patients with schizophrenia to improve their potential for community functioning.

Cooperative Studies Program (CSP) #572: A Study of Serious Mental Illness in Veterans as a Pathway to personalized medicine in Schizophrenia and Bipolar Illness

BACKGROUND

Personalization of psychiatric treatment includes treatment of symptoms, cognition and functional deficits, suicide, and medical co-morbidities. VA Collaborative Study 572 examined a large sample of male and female veterans with schizophrenia (n=3,942) and with bipolar disorder (n=5,414) with phenotyping and genomic analyses. We present the results to date and future directions.

METHODS

All veterans received a structured diagnostic interview and assessments of suicidal ideation and behavior, PTSD, and health. Veterans with schizophrenia were assessed for negative symptoms and lifetime depression. All were assessed with a cognitive and functional capacity assessment. Data for genome wide association studies were collected. Controls came from the VA Million Veteran Program.

RESULTS

Suicidal ideation or behavior was present in 66%. Cognitive and functional deficits were consistent with previous studies. 40% of the veterans with schizophrenia had a lifetime major depressive episode and PTSD was present in over 30%. Polygenic risk score (PRS) analyses indicated that cognitive and functional deficits overlapped with PRS for cognition, education, and intelligence in the general population and PRS for suicidal ideation and behavior correlated with previous PRS for depression and suicidal ideation and behavior, as did the PRS for PTSD.

DISCUSSION

Results to date provide directions for personalization of treatment in SMI, veterans with SMI, and veterans in general. The results of the genomic analyses suggest that cognitive deficits in SMI may be associated with general population features. Upcoming genomic analyses will reexamine the issues above, as well as genomic factors associated with smoking, substance abuse, negative symptoms, and treatment response.

Bifactor model of cognition in schizophrenia: Evidence for general and specific abilities

BACKGROUND

Despite extensive study of cognition in schizophrenia, it remains unclear as to whether cognitive deficits and their latent structure are best characterized as reflecting a generalized deficit, specific deficits, or some combination of general and specific constructs.

METHOD

To clarify latent structure of cognitive abilities, confirmatory factor analysis was used to examine the latent structure of cognitive data collected for the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) for Schizophrenia study. Baseline assessment data (n = 813) were randomly divided into calibration (n = 413) and cross-validation samples (n = 400). To examine whether generalized or specific deficit models provided better explanation of the data, we estimated first-order, hierarchical, and bifactor models.

RESULTS

A bifactor model with seven specific factors and one general factor provided the best fit to the data for both the calibration and cross-validation samples.

CONCLUSIONS

These findings lend support for a replicable bifactor model of cognition in schizophrenia, characterized by both a general cognitive factor and specific domains. This suggests that cognitive deficits in schizophrenia might be best understood by separate general and specific contributions.

The Computerized Functional Skills Assessment and Training Program: Sensitivity to Global Cognitive Impairment, Correlations With Cognitive Abilities, and Factor Structure

OBJECTIVES

We evaluated a novel computer-based functional skills assessment and training (CFSAT) program, which includes ecologically valid simulations of six everyday technology-related tasks. In this report, we describe the psychometric properties of the assessment in terms of sensitivity to impairment, factor structure and correlations with cognitive performance.

DESIGN

Cross-sectional baseline assessment prior to a treatment study.

PARTICIPANTS

Noncognitively impaired older adults (n = 62) and cognitively impaired older adults (n = 55), that ranged in age from 60 to 86 years (M = 73.12), was primarily female (90%), and ethnically diverse (21% Hispanic, 52% African American). Participants were divided at baseline on the basis of MOCA scores and cognitive complaints.

MEASUREMENTS

The Brief Assessment of Cognition (BAC), app version, was used to measure cognitive performance and completion times on the six subtasks of the CFAST constituted the functional capacity measures.

RESULTS

Performance on the CFSAT and BAC discriminated the two cognitive status groups. All of the cognitive domains on the BAC correlated significantly with all six CFSAT subtasks (all p < .01). Factor analyses suggested that the CFSAT and the BAC loaded on separate factors and regression analyses indicated that executive functioning and processing speed had the largest independent association with performance on the CFSAT.

CONCLUSION

The CFSAT is sensitive to functional impairments seen in cognitively impaired older adults. Cognitive performance and CFSAT scores were related but nonredundant. Thus, the CFSAT appears to identify functional deficits that could be targeted with skills training interventions, likely augmented by pharmacological or computerized cognitive training interventions.

Factor structure of cognitive performance and functional capacity in schizophrenia: Evidence for differences across functional capacity measures

BACKGROUND

Cognition and functional capacity predict functional outcomes in mental illness. Traditional approaches conceptualize cognition as comprised of domains, but many studies support a unifactorial structure. Some functional capacity measures may share a single-factor structure with cognition. In this study, we examined the factor structure of two measures of functional capacity, a conventional assessment and a newer computerized assessment, testing for a shared factor structure with cognition.

METHODS

Patients with schizophrenia and healthy controls were examined with the MATRICS Consensus Cognitive Battery (MCCB), the UCSD Performance Based Skills Assessment (UPSA), and the Virtual Reality Functional Capacity Assessment Tool (VRFCAT). Models of the factor structures of the MCCB, UPSA, and VRFCAT were calculated, as were correlations between MCCB scores and individual VRFCAT objectives.

RESULTS

The MCCB, VRFCAT, and UPSA all had unifactorial structures. The best fitting model of the correlations between MCCB and UPSA was a shared single factor, while the best fit for the relationship between MCCB and VRFCAT had two factors. Correlations between the MCCB domain and composite scores and the VRFCAT objectives suggested global rather than specific patterns of correlation.

DISCUSSION

The relationship between cognitive performance and functional capacity was found to vary across functional capacity assessments. The UPSA and MCCB were not differentiated into separate factors, suggesting that the UPSA may overlap with neurocognitive performance. However, the VRFCAT appears to measure functional abilities that are separable from, yet correlated with, neurocognitive performance. It may provide a more distinctive assessment of the functional capacity construct.

Transdiagnostic validity of the MATRICS Consensus Cognitive Battery across the autism-schizophrenia spectrum

BACKGROUND

Autism Spectrum Disorder (ASD) and schizophrenia are neurodevelopmental disorders which share substantial overlap in cognitive deficits during adulthood. However, treatment evaluation in ASD and treatment comparisons across ASD and schizophrenia are limited by a dearth of empirical work establishing the validity of a standard cognitive battery across ASD and schizophrenia. Promisingly, the MATRICS Consensus Cognitive Battery (MCCB) has been validated in schizophrenia and encompasses cognitive domains that are impacted in ASD. Thus, this study aimed to establish MCCB's generalizability from schizophrenia to ASD.

METHODS

Community-residing adults with schizophrenia (N = 100) and ASD (N = 113) underwent MCCB assessment. Using multigroup confirmatory factor analysis, MCCB's transdiagnostic validity was evaluated by examining whether schizophrenia and ASD demonstrate the same configuration, magnitude, and directionality of relationships within and among measures and their underlying cognitive domains.

RESULTS

Across schizophrenia and ASD, the same subsets of MCCB measures inform three cognitive domains: processing speed, attention/working memory, and learning. Except for group means in category fluency, continuous performance, and spatial span, both groups show vastly comparable factor structures and characteristics.

CONCLUSIONS

To our knowledge, this study is the first to establish the validity of a standard cognitive battery in adults with ASD and furthermore the first to establish a cognitive battery's comparability across ASD and schizophrenia. Cognitive domain scores can be compared across new samples using weighted sums of MCCB scores resulting from this study. These findings highlight MCCB's applicability to ASD and support its utility for standardizing treatment evaluation of cognitive outcomes across the autism-schizophrenia spectrum.

Neurocognitive variability in schizophrenia spectrum disorders: relationship to real-world functioning

Neurocognitive variability exists within the schizophrenia spectrum disorder (SSD) population, with subgroups performing at the same level as healthy samples Here we study the relationship between different levels of neurocognitive responding and real-world functioning. The participants were 291 SSD patients and 302 healthy controls that were assessed with a comprehensive neurocognitive battery. In addition, the patients were assessed with the Specific Level of Functioning Scale (SLOF). The results showed that the mean neurocognitive test responses of the SSD group were significantly below that of the control group. However, there was considerable overlap between the cognitive scores of the two groups, with as many as 24% of the patients performing above the mean healthy score for some domains. Moreover, the patients with the highest level of neurocognitive functioning reached the highest levels of practical and work-related functioning outcome skills. There was no significant relationship between neurocognitive and social function skills. The large differences in cognitive performance and their associations with functional outcome within the patient group are rarely addressed in clinical practice, but indicate a clear need for individualized treatment of SSD. Early identification of cognitive risk factors for poor real-life functional outcome is necessary in order to alert the clinical and rehabilitation services about patients in need of extra care.

Predictive factors of functional capacity and real-world functioning in patients with schizophrenia

Purpose

This study was performed to identify the predictive factors of functional capacity assessed by the Spanish University of California Performance Skills Assessment (Sp-UPSA) and real-world functioning assessed by the Spanish Personal and Social Performance scale (PSP) in outpatients with schizophrenia.

Methods

Naturalistic, 6-month follow-up, multicentre, validation study. Here, we report data on 139 patients with schizophrenia at their baseline visit. Assessment: Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression-Severity (CGI-S), Sp-UPSA and PSP. Statistics: Pearson's correlation coefficient (r) was used to determine the relationships between variables, and multivariable stepwise linear regression analyses to identify predictive variables of Sp-UPSA and PSP total scores.

Results

Functional capacity: scores on the PSP and PANSS-GP entered first and second at P < 0.0001 and accounted for 21% of variance (R2 = 0.208, model df = 2, F = 15.724, P < 0.0001). Real-world functioning: scores on the CGI-S (B = −5.406), PANSS-N (B = −0.657) and Sp-UPSA (B = 0.230) entered first, second and third, and accounted for 51% of variance (model df = 3, F = 37.741, P < 0.0001).

Conclusion

In patients with schizophrenia, functional capacity and real-world functioning are two related but different constructs. Each one predicts the other along with other factors; general psychopathology for functional capacity, and severity of the illness and negative symptoms for real-world functioning. These findings have important clinical implications: (1) both types of functioning should be assessed in patients with schizophrenia and (2) strategies for improving them should be different.

Profile of cognitive deficits in schizophrenia and factor structure of the Czech MATRICS Consensus Cognitive Battery

We aimed to validate the Czech version of the MATRICS Consensus Cognitive Battery (MCCB). The MCCB is a test battery designed to assess cognitive treatment effects in clinical trials of patients with schizophrenia. The valid, reliable and replicable measurement of cognition in schizophrenia is of substantial importance for such clinical trial studies. We performed a psychometric analysis of the MCCB composite and domain scores based on ROC analysis of 67 schizophrenia patients and 67 age- and education-matched healthy controls from a total sample of 220 controls. Also, we correlated MCCB variables with scales measuring psychosocial functioning (Personal and Social Performance scale; PSP). The internal consistency of all 10 tests in the MCCB battery was good (Cronbach's α = 0.85 (95% CI [0.83, 0.88])). The discriminative validity for the detection of neurocognitive dysfunction in schizophrenia based on the area under the curve of MCCB composite T-score was ≥90% (95% CI [0.85, 0.96]) and all MCCB domains showed ps < .001. The MCCB global composite and the Speed of Processing domain score significantly predicted the PSP ratings. A confirmatory factor analysis on the whole control sample (N = 220) showed an optimal fit for a 6-factor in comparison to 1-factor solution. In conclusion, we found high discriminative validity for the Czech MCCB version, similar to the differentiation of schizophrenia versus healthy control groups in the original MCCB studies. We also established the factorial validity of the MCCB and showed that the overall composite of the MCCB predicts psychosocial functioning in the patient group.

Genome-wide association study of cognitive performance in U.S. veterans with schizophrenia or bipolar disorder

Cognitive impairment is a frequent and serious problem in patients with various forms of severe mental illnesses (SMI), including schizophrenia (SZ) and bipolar disorder (BP). Recent research suggests genetic links to several cognitive phenotypes in both SMI and in the general population. Our goal in this study was to identify potential genomic signatures of cognitive functioning in veterans with severe mental illness and compare them to previous findings for cognition across different populations. Veterans Affairs (VA) Cooperative Studies Program (CSP) Study #572 evaluated cognitive and functional capacity measures among SZ and BP patients. In conjunction with the VA Million Veteran Program, 3,959 European American (1,095 SZ, 2,864 BP) and 2,601 African American (1,095 SZ, 2,864 BP) patients were genotyped using a custom Affymetrix Axiom Biobank array. We performed a genome-wide association study of global cognitive functioning, constructed polygenic scores for SZ and cognition in the general population, and examined genetic correlations with 2,626 UK Biobank traits. Although no single locus attained genome-wide significance, observed allelic effects were strongly consistent with previous studies. We observed robust associations between global cognitive functioning and polygenic scores for cognitive performance, intelligence, and SZ risk. We also identified significant genetic correlations with several cognition-related traits in UK Biobank. In a diverse cohort of U.S. veterans with SZ or BP, we demonstrate broad overlap of common genetic effects on cognition in the general population, and find that greater polygenic loading for SZ risk is associated with poorer cognitive performance.

Relationships among functional capacity, cognition, and naturalistic skill performance in people with serious mental illness

There has been increasing interest in understanding real-world outcomes for individuals with serious mental illnesses (SMI). This study examined domain-specific skill knowledge, functional capacity, and neurocognition as predictors of naturalistic grocery shopping skill performance in forty-eight individuals with SMI. Participants completed measures of skill knowledge and general functional capacity (UCSD Performance-Based Skill Assessment - brief) as well as measures of neurocognition and symptoms. The Test of Grocery-Shopping Skills (TOGSS) assessed naturalistic shopping. TOGSS was significantly correlated with functional capacity, shopping skill knowledge, and neurocognition, but not symptoms. Multiple regression analysis was conducted with variables entered in 2 blocks. Skill knowledge and functional capacity were entered in block 1. Neurocognitive measures were entered in block 2 using forward entry. Skill knowledge was not a significant predictor of TOGSS when accounting for functional capacity and neurocognition. Functional capacity predicted TOGSS over and above skill knowledge and remained significant after accounting for the effects of neurocognition. Our findings indicate that functional capacity was associated with skill assessment under naturalistic conditions. Further, there was some, but not complete, overlap between neurocognitive and functional capacity predictors of naturalistic skill performance. Further development of naturalistic assessments may hold promise for interventions targeting real-world function.

A 10-minute measure of global cognition: Validation of the Brief Cognitive Assessment Tool for Schizophrenia (B-CATS)

INTRODUCTION

Schizophrenia is marked by a global cognitive impairment that contributes significantly to chronic disability and unemployment. As new treatments are developed for cognition in schizophrenia, clinicians require easily administered instruments to assess cognition. We previously developed a very brief cognitive battery (Bell et al., 2005). The Brief Cognitive Assessment Tool for Schizophrenia (B-CATS) was developed specifically to provide clinicians with a way to assess cognition in their patients with schizophrenia. Here, we report the results of a validity study comparing B-CATS to a larger neurocognitive battery, the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) battery.

METHODS

Outpatients with schizophrenia (N=91) were administered the B-CATS and the non-overlapping tests of the MATRICS battery at two time points separated by 1month. They were also administered the UCSD Performance-based Skills Assessment-Brief (UPSA-B), a measure of functional capacity.

RESULT

The B-CATS has an administration time of approximately 10min. It demonstrates good test-retest reliability and internal consistency. It correlates 0.76 (p<0.01) with the MATRICS battery. The shorter B-CATS and the MATRICS battery correlate with the UPSA-B at 0.50 and 0.58 respectively.

CONCLUSION

A 10-minute version of the B-CATS correlates highly with the "gold standard" neurocognitive battery that has an administration time of over 60min. Both measures correlate moderately with a measure of functional capacity. This brief battery was designed to allow clinicians to monitor cognitive change and better inform treatment decisions.

Systematic Review of Measurement Property Evidence for 8 Financial Management Instruments in Populations With Acquired Cognitive Impairment

OBJECTIVES

To critically appraise the measurement property evidence (ie, psychometric) for 8 observation-based financial management assessment instruments.

DATA SOURCES

Seven databases were searched in May 2015.

STUDY SELECTION

Two reviewers used an independent decision-agreement process to select studies of measurement property evidence relevant to populations with adulthood acquired cognitive impairment, appraise the quality of the evidence, and extract data. Twenty-one articles were selected.

DATA EXTRACTION

This review used the COnsensus-based Standards for the selection of health Measurement Instruments review guidelines and 4-point tool to appraise evidence. After appraising the methodologic quality, the adequacy of results and volume of evidence per instrument were synthesized. Measurement property evidence with high risk of bias was excluded from the synthesis.

DATA SYNTHESIS

The volume of measurement property evidence per instrument is low; most instruments had 1 to 3 included studies. Many included studies had poor methodologic quality per measurement property evidence area examined. Six of the 8 instruments reviewed had supporting construct validity/hypothesis-testing evidence of fair methodologic quality. There is a dearth of acceptable quality content validity, reliability, and responsiveness evidence for all 8 instruments.

CONCLUSIONS

Rehabilitation practitioners assess financial management functions in adults with acquired cognitive impairments. However, there is limited published evidence to support using any of the reviewed instruments. Practitioners should exercise caution when interpreting the results of these instruments. This review highlights the importance of appraising the quality of measurement property evidence before examining the adequacy of the results and synthesizing the evidence.

Factor structure of cognition and functional capacity in two studies of schizophrenia and bipolar disorder: Implications for genomic studies

OBJECTIVE

Impairments in cognition and everyday functioning are common in schizophrenia and bipolar disorder (BPD). In this article, we present factor analyses of cognitive and functional capacity (FC) measures based on 2 studies of schizophrenia (SCZ) and bipolar I disorder (BPI) using similar methods. The overall goal of these analyses was to determine whether performance-based assessments should be examined individually, or aggregated on the basis of the correlational structure of the tests, as well as to evaluate the similarity of factor structures of SCZ and BPI.

METHOD

Veterans Affairs Cooperative Studies Program Study #572 (Harvey et al., 2014) evaluated cognitive and FC measures among 5,414 BPI and 3,942 SCZ patients. A 2nd study evaluated similar neuropsychological (NP) and FC measures among 368 BPI and 436 SCZ patients. Principal components analysis, as well as exploratory and CFAs, were used to examine the data.

RESULTS

Analyses in both datasets suggested that NP and FC measures were explained by a single underlying factor in BPI and SCZ patients, both when analyzed separately or as in a combined sample. The factor structure in both studies was similar, with or without inclusion of FC measures; homogeneous loadings were observed for that single factor across cognitive and FC domains across the samples.

CONCLUSION

The empirically derived factor model suggests that NP performance and FC are best explained as a single latent trait applicable to people with SCZ and BPD. This single measure may enhance the robustness of the analyses relating genomic data to performance-based phenotypes.

A confirmatory factor analysis of the MATRICS consensus cognitive battery in severe mental illness

BACKGROUND

A recent factor analysis of Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) data in a sample of schizophrenia-spectrum patients described a three factor model representing processing speed, attention/working memory, and learning; the social cognition measure was excluded from the analysis. The current analyses sought to replicate a three factor structure of the MCCB in a larger, more diagnostically diverse sample of participants.

METHODS

Confirmatory factor analyses were performed to evaluate the factor structure of the MCCB in 300 outpatients with severe mental illness (54.3% schizophrenia-spectrum diagnoses) who were participants in three studies of cognitive remediation. Exploratory analyses were conducted to evaluate the concurrent prediction of symptoms from MCCB factor scores.

RESULTS

The three factor structure of the MCCB demonstrated stronger model fit (χ(2)=14.53, p=0.75, SRMR=0.02, RMSEA=0.0, CFI=1.00, NNFI=1.01) than the unifactoral structure. Poorer cognitive performance across all three MCCB factors was significantly correlated with more severe overall and disorganization symptoms from the PANSS and BPRS, and less severe affective symptoms (e.g., depression, anxiety) in the overall sample.

CONCLUSIONS

A three factor structure of the MCCB-composed of processing speed, attention/working memory, and learning-was replicated in a heterogeneous sample of persons with severe mental illness. Cognitive performance on the MCCB factors is associated with clinical symptoms.

The impact of aging, cognition, and symptoms on functional competence in individuals with schizophrenia across the lifespan

OBJECTIVE

Life expectancy in individuals with schizophrenia continues to increase. It is not clear whether cognitive deficits associated with schizophrenia remain as strong predictors of function in older and younger individuals. Thus, we assessed the relationship between cognition and functional competence in individuals with schizophrenia across 7 decades of life.

METHODS

We analyzed data obtained in 232 community-dwelling participants with schizophrenia (age range: 19-79 years). Cognition was assessed using the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery. Functional competence was assessed using the UCSD Performance-based Skills Assessment, which includes measures of Comprehension and Planning of Recreational Activities Skills, Financial Skills, Communication Skills, Transportation Skills, and Household Management Skills. To assess the effects of Global Cognition on functional competence, we performed hierarchical multivariate linear or logistic regression analyses controlling for age, education, gender, and negative symptoms.

RESULTS

Participants' mean age was 49.1 (SD = 13.2, range = 19-79 years), 161 (69%) were male, and 55 (24%) were aged ≥60. Global Cognition was a predictor of Comprehension and Planning Skills (Exp(β) = 1.048), Financial Skills (Exp(β) = 1.104), Communication Skills (ΔR (2) = .31) and Transportation Skills (Exp(β) = 1.066), but not Household Management Skills after adjusting for age, education, gender, and negative symptoms of schizophrenia.

CONCLUSION

Cognition remains a strong predictor of functional competence across the lifespan. These findings suggest that treating cognitive impairment associated with schizophrenia could improve individuals' function independent of their age.

Commissions and omissions are dissociable aspects of everyday action impairment in schizophrenia

Prior research using performance-based assessment of functional impairment has informed a novel neuropsychological model of everyday action impairment in dementia in which omission errors (i.e., failure to complete task steps) dissociate from commission errors (i.e., inaccurate performance of task steps) and have unique neuropsychological correlates. However, this model has not been tested in other populations. The present study examined whether this model extends to schizophrenia. Fifty-four individuals with schizophrenia or schizoaffective disorder were administered a neuropsychological protocol and the Naturalistic Action Test (NAT), a performance-based measure of everyday action. A principal component analysis (PCA) was performed to examine the construct(s) comprising everyday action impairment, and correlations between the resultant component(s) and neuropsychological tests were examined. Results showed that omissions and a subset of commissions were distinct components of everyday action. However, results did not support unique associations between these components and specific neuropsychological measures. These findings extend the omission-commission model to schizophrenia and may have important implications for efficient assessment and effective rehabilitation of functional impairment, such as the potential efficacy of targeted interventions for the rehabilitation of omission and commission deficits in everyday functioning. Larger studies with prospective designs are needed to replicate the present preliminary findings.

The genetics of functional disability in schizophrenia and bipolar illness: Methods and initial results for VA cooperative study #572

Given the prominence of cognitive impairments and disability associated with schizophrenia and bipolar disorder, substantial interest has arisen in identifying determinants of the diseases and their features. Genetic variation has been linked to skills that underlie disability ("functional capacity" or FC), highlighting need for understanding of these relationships. We describe the design and methods of a large, multisite, observational study focusing on the genetics of functional disability in schizophrenia and bipolar disorder, presenting initial data on recruitment, and characterization of the sample. Known as Veterans Affairs (VA) Cooperative Studies Program (CSP)#572, this study is recruiting, diagnosing, and assessing U.S. Veterans with either schizophrenia or bipolar I disorder. Assessments include neuropsychological (NP) testing, FC, suicidality, and co-morbid conditions such as posttraumatic stress disorder (PTSD). A sample of "psychiatrically healthy" Veterans from another project serves as a comparison group. An interim total of 8,140 participants (42.1% schizophrenia) have been recruited and assessed as of September 30, 2013, with 9 months of enrollment remaining and with a target sample size of 9,500. Veterans with schizophrenia were more likely to never have married, whereas lifetime PTSD and suicidality were more common in the bipolar veterans. Performance on the FC measures and NP tests was consistent with previous results, with mean t-scores of 35 (-1.5 SD) for schizophrenia and 41 (-0.9 SD) for the bipolar Veterans. This large population is representative of previous studies in terms of patient performance and co-morbidities. Subsequent genomic analyses will examine the genomic correlates of performance-based measures. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Development of a virtual reality assessment of everyday living skills

Cognitive impairments affect the majority of patients with schizophrenia and these impairments predict poor long term psychosocial outcomes.  Treatment studies aimed at cognitive impairment in patients with schizophrenia not only require demonstration of improvements on cognitive tests, but also evidence that any cognitive changes lead to clinically meaningful improvements.  Measures of "functional capacity" index the extent to which individuals have the potential to perform skills required for real world functioning.  Current data do not support the recommendation of any single instrument for measurement of functional capacity.  The Virtual Reality Functional Capacity Assessment Tool (VRFCAT) is a novel, interactive gaming based measure of functional capacity that uses a realistic simulated environment to recreate routine activities of daily living. Studies are currently underway to evaluate and establish the VRFCAT's sensitivity, reliability, validity, and practicality. This new measure of functional capacity is practical, relevant, easy to use, and has several features that improve validity and sensitivity of measurement of function in clinical trials of patients with CNS disorders.

Cognition in schizophrenia: Past, present, and future

Schizophrenia Research: Cognition will serve an important function - a place where interests converge and investigators can learn about the recent developments in this area. This new journal will provide rapid dissemination of information to people who will make good use of it. In this initial article, we comment globally on the study of cognition in schizophrenia: how we got here, where we are, and where we are going. The goal of this first article is to place the study of cognition in schizophrenia within a historical and scientific context. In a field as richly textured as ours it is impossible to hit all the important areas, and we hope the reader will forgive our omissions. Phrased in cognitive terms, our limited presentation of the past is a matter of selective memory, the present is a matter of selective attention, and the future is a matter of selective prospection. This broad introduction emphasizes that cognition in schizophrenia provides clues to pathophysiology, treatment, and outcome. In fact, the study of cognitive impairment in schizophrenia has become wholly intertwined with the study of schizophrenia itself.

The relationship between executive functions and fluid intelligence in schizophrenia

An enduring question is unity vs. separability of executive deficits resulting from impaired frontal lobe function. In previous studies, we have asked how executive deficits link to a conventional measure of fluid intelligence, obtained either by standard tests of novel problem-solving, or by averaging performance in a battery of novel tasks. For some classical executive tasks, such as the Wisconsin Card Sorting Test (WCST), Verbal Fluency, and Trail Making Test B (TMTB), frontal deficits are entirely explained by fluid intelligence. However, on a second set of executive tasks, including tests of multitasking and decision making, deficits exceed those predicted by fluid intelligence loss. In this paper we discuss how these results shed light on the diverse clinical phenomenology observed in frontal dysfunction, and present new data on a group of 15 schizophrenic patients and 14 controls. Subjects were assessed with a range of executive tests and with a general cognitive battery used to derive a measure of fluid intelligence. Group performance was compared and fluid intelligence was introduced as a covariate. In line with our previous results, significant patient-control differences in classical executive tests were removed when fluid intelligence was introduced as a covariate. However, for tests of multitasking and decision making, deficits remained. We relate our findings to those of previous factor analytic studies describing a single principal component, which accounts for much of the variance of schizophrenic patients' cognitive performance. We propose that this general factor reflects low fluid intelligence capacity, which accounts for much but not all cognitive impairment in this patient group. Partialling out the general effects of fluid intelligence, we propose, may clarify the role of additional, more specific cognitive impairments in conditions such as schizophrenia.