Generalized Cognitive Deficits in Schizophrenia

Mohamed, Somaia; Paulsen, Jane S.; O'Leary, Daniel S.; Arndt, Stephan; Andreasen, Nancy C.

doi:10.1001/archpsyc.56.8.749

Cited by 405 publications

(255 citation statements)

References 33 publications

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“…The magnitude of the correlations between cognition and clinical symptoms in schizophrenia has been inconsistent, but generally small (Goldberg et al, 1993;Addington et al, 1991;Hughes et al, 2003;Strauss, 1993;Mohamed et al, 1999;Bilder et al, 2000;Gladsjo et al, 2004). This finding, which may contradict clinicians' impressions, could potentially be explained by the possibility that patients who agree to participate in research studies do not reflect the general population of patients with schizophrenia, especially for those studies with extensive and demanding neurocognitive batteries.…”

Section: Discussionmentioning

confidence: 99%

Baseline Neurocognitive Deficits in the CATIE Schizophrenia Trial

Keefe

Bilder²,

Harvey

et al. 2006

Neuropsychopharmacol

420

293

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Neurocognition is moderately to severely impaired in patients with schizophrenia. However, the factor structure of the various neurocognitive deficits, the relationship with symptoms and other variables, and the minimum amount of testing required to determine an adequate composite score has not been determined in typical patients with schizophrenia. An 'all-comer' approach to cognition is needed, as provided by the baseline assessment of an unprecedented number of patients in the CATIE (Clinical Antipsychotic Trials of Intervention Effectiveness) schizophrenia trial. From academic sites and treatment providers representative of the community, 1493 patients with chronic schizophrenia were entered into the study, including those with medical comorbidity and substance abuse. Eleven neurocognitive tests were administered, resulting in 24 individual scores reduced to nine neurocognitive outcome measures, five domain scores and a composite score. Despite minimal screening procedures, 91.2% of patients provided meaningful neurocognitive data. Exploratory principal components analysis yielded one factor accounting for 45% of the test variance. Confirmatory factor analysis showed that a single-factor model comprised of five domain scores was the best fit. The correlations among the factors were medium to high, and scores on individual factors were very highly correlated with the single composite score. Neurocognitive deficits were modestly correlated with negative symptom severity (r ¼ 0.13-0.27), but correlations with positive symptom severity were near zero (ro0.08). Even in an 'all-comer' clinical trial, neurocognitive deficits can be assessed in the overwhelming majority of patients, and the severity of impairment is similar to meta-analytic estimates. Multiple analyses suggested that a broad cognitive deficit characterizes this sample. These deficits are modestly related to negative symptoms and essentially independent of positive symptom severity.

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Section: Discussionmentioning

confidence: 99%

Baseline Neurocognitive Deficits in the CATIE Schizophrenia Trial

Keefe

Bilder²,

Harvey

et al. 2006

Neuropsychopharmacol

420

293

View full text Add to dashboard Cite

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“…Cognitive studies have shown that executive function and working memory deficits related to the anterior CG (Carter et al, 2001;Morey et al, 2005;Szeszko et al, 2000) are present in most schizophrenic individuals Mohamed et al, 1999;Silver et al, 2003;Snitz et al, 2006). Neuroimaging studies have directly linked these deficits to the CG.…”

Section: Discussionmentioning

confidence: 99%

“…As part of the limbic system, the CG is involved in executive function and shares numerous connections with prefrontal cortex and hippocampus (Bush, Luu, & Posner, 2000), two other regions significantly altered in schizophrenia (Gur, Keshavan, & Lawrie, 2007;Suzuki et al, 2005). Moreover, cognitive impairments linked with both of these structures, specifically executive function and working memory, are considered as putative endophenotypes and core features for schizophrenia Mohamed, Paulsen, O'Leary, Arndt, & Andreasen, 1999;Silver, Feldman, Bilker, & Gur, 2003;Snitz, Angus, MacDonald, & Carter, 2006). Increasing interest is given to identifying such potential endophenotypes, which represent important markers for the complex relationships between genes, brain and related cognitive functions.…”

Section: Introductionmentioning

confidence: 99%

Cingulate gyral reductions are related to low executive functioning and psychotic symptoms in 22q11.2 deletion syndrome

et al. 2008

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“…Cognitive impairment is a key feature of schizophrenia (Mohamed et al, 1999;Zanelli et al, 2010;Matheson et al, 2011) and also occurs, though to a lesser extent, in affective psychosis (Krabbendam et al, 2005;Kravariti et al, 2009). However, not all psychotic patients show cognitive impairment (Kremen et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Cannabis users have higher premorbid IQ than other patients with first onset psychosis

Ferraro

Russo

O’Connor

et al. 2013

Schizophrenia Research

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a b s t r a c t a r t i c l e i n f oBackground: A number of studies have reported that patients with psychosis who use cannabis have better cognitive performance than those who do not. This is surprising as cannabis can impair cognition in healthy subjects. An obvious question is whether the better current performance of psychotic patients who have used cannabis is a reflection of their having a higher premorbid IQ than those psychotic patients who haven't used cannabis. Aim: In a sample of patients at their first episode of psychosis, we tested the hypothesis that patients who smoked cannabis would have a higher premorbid IQ than patients who did not. Methodology: 279 participants (119 patients and 160 healthy controls) were assessed in order to obtain current and premorbid IQ measures and detailed information on cannabis use. We examined the association between cannabis use and both premorbid and current IQ in patients and controls. Results: Patients who had ever smoked cannabis had significantly higher current (p b .001) and premorbid IQ (p = .004) compared to patients who had never used cannabis. This difference was not found among controls. Conclusions: These findings suggest that the better cognitive performance of patients with their first episode of psychosis who have used cannabis compared with those who haven't is due to the better premorbid IQ of the former.

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Generalized Cognitive Deficits in Schizophrenia

Cited by 405 publications

References 33 publications

Baseline Neurocognitive Deficits in the CATIE Schizophrenia Trial

Baseline Neurocognitive Deficits in the CATIE Schizophrenia Trial

Cingulate gyral reductions are related to low executive functioning and psychotic symptoms in 22q11.2 deletion syndrome

Cannabis users have higher premorbid IQ than other patients with first onset psychosis

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