Article

General and specific cognitive deficits in schizophrenia

Veterans Affairs Capitol Health Care Network, Mental Illness Research, Education, and Clinical Center, 10 North Greene Street, Suite 6A, Baltimore, MD 21201, USA.
Biological Psychiatry (Impact Factor: 10.26). 05/2004; 55(8):826-33. DOI: 10.1016/j.biopsych.2003.12.010
Source: PubMed

ABSTRACT

It is controversial whether the cognitive deficit in schizophrenia is better characterized as generalized or as reflecting relatively independent deficits in different cognitive domains. The issue has implications for assessment practice, intervention design, and the exploration of schizophrenia genetics.
We used a specialized structural equation modeling approach, single common factor analysis, to explore the relative importance of generalized versus independent cognitive deficits in schizophrenia. Eighteen subtest scores from the Wechsler Adult Intelligence Scale-III and the Wechsler Memory Scale-III were included in the analysis. We analyzed these data for 97 schizophrenia or schizoaffective disorder outpatients and 87 healthy control subjects.
Approximately two thirds of the overall effect of a schizophrenia diagnosis on cognitive performance was mediated through a single common factor. The Wechsler subtest scores showed almost uniformly strong relationships with this factor. The independent associations of group status with the subtest scores were smaller in magnitude and only selectively significant.
The relatively greater magnitude of illness effects mediated through the common factor in this analysis, compared with the specific, independent effects, suggests that a generalized cognitive deficit is a core feature of schizophrenia.

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    • "In sum, cognitive function and psychiatric symptoms are considered to play a major role in social functioning in patients with schizophrenia (Bowie et al., 2008). General cognitive function is assessed by performance on neuropsychological tests of most cognitive domains (Dickinson et al., 2004) and has Schizophrenia Research: Cognition 3 (2015) 20–25 ⁎ Corresponding author. Tel./fax: +81 668793074. "
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    ABSTRACT: Although impaired social functioning, particularly poor employment status, is a cardinal feature of patients with schizophrenia and leads to decreased quality of life (QOL), few studies have addressed the relationship between these two clinical issues. The aim of this study was to determine whether employment status predicts subjective QOL and to evaluate a model in which functional capacity mediates the relationship between general cognitive performance and employment status. Ninety-three patients with schizophrenia were administered a comprehensive battery of cognitive tests, the UCSD Performance-based Skills Assessment-Brief version (UPSA-B), the Social Functioning Scale (SFS), and the Subjective Quality of Life Scale (SQLS). First, we evaluated a model for predicting the employment/occupation subscale score of the SFS using path analysis, and the model fitted well (χ2 (4)=3.6, p=0.46; CFI=1.0; RMSEA<0.001, with 90% CIs: 0–0.152). Employment status was predicted by negative symptoms and functional capacity, which was in turn predicted by general cognitive performance. Second, we added subjective QOL to this model. In a final path model, QOL was predicted by negative symptoms and employment status. This model also satisfied good fit criteria (χ2 (7)=10.3, p=0.17; CFI=0.987; RMSEA=0.072, with 90% CIs: 0–0.159). The UPSA-B and SFS scores were moderately correlated with most measures of cognitive performance. These results support the notion that better employment status enhances subjective QOL in patients with schizophrenia.
    Full-text · Article · Mar 2016 · Schizophrenia Research: Cognition
    • "For instance, the results of the large-scale (n 1,332) Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) study baseline neurocognitive assessment (Keefe et al., 2006) found that a singlefactor structure fit the data better than more complex models. In addition, and consistent with earlier results (Dickinson, Iannone, Wilk, &amp; Gold, 2004), a few of the measures accounted for the majority of the variance in the composite scores. In a smaller and separate sample from this study, assessing only people with SCZ (Harvey et al. 2013), it was also found that neuropsychological testing and FC performance constituted a single factor that met all criteria for multivariate longitudinal stability of all indicators (factor scores, factor loadings, and error covariances) over a follow-up period of between 6 weeks to 6 months. "
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    ABSTRACT: 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. (PsycINFO Database Record
    No preview · Article · Dec 2015 · Neuropsychology
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    • "Cognitive impairments in memory, attention and executive functions (Nuechterlein et al., 2004) are critical determinants of functional disability in schizophrenia (Dickinson et al., 2004; Heinrichs and Zakzanis, 1998). Recently, emphasis has been placed on sensory and perceptual impairments , which are also critical in schizophrenia (Nelson et al., 2014; Postmes et al., 2014), and several types of sensory remediation have been proposed (Adcock et al., 2009; Fisher et al., 2009). "
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    ABSTRACT: Metabolic syndrome is more prevalent in schizophrenia than in the general population and is associated with an increased rate of morbidity. It has been associated with cognitive impairments in schizophrenia, which are a core deficit in patients with chronic schizophrenia. Sensory gating deficit is also a core deficit in schizophrenia. The principal objective of this study was to investigate the relationship between sensory gating deficit and metabolic syndrome in patients with schizophrenia, after adjusting for key confounding factors. We hypothesized that patients with metabolic syndrome exhibit a higher rate of sensory gating deficit compared to those without metabolic syndrome. This study investigated sensory gating with the auditory event-related potential method by measuring P50 amplitude changes in a double click conditioning-testing procedure in 51 patients with schizophrenia. Patients with metabolic syndrome (n = 14) had a higher rate of sensory gating deficit (P50 suppression < 50%) (p < 0.001) compared to those without metabolic syndrome (n = 37). This result remained significant (B = 2.94, Wald = 8.32, p = 0.004) after taking into account 5 potential confounding factors (age, gender, duration of disorder, Fagerström test, presence of clozapine or olanzapine). In patients without metabolic syndrome, sensory gating deficit was linked to a poorer attentional performance (rho = -0.371, p = 0.05). In patients with metabolic syndrome, sensory gating deficit was linked to poorer memory performance (rho = -0.635, p = 0.02). These findings suggest that metabolic syndrome may be linked to sensory gating deficit in patients with schizophrenia and that the relationship between neurocognitive function and sensory gating deficit could be affected by the metabolic status of the patients. Further studies are needed to address the causal relationship between sensory gating deficit related to schizophrenia, cognitive impairments and metabolic syndrome.
    Full-text · Article · Apr 2015 · Psychoneuroendocrinology
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