Neurocognitive Deficit in Schizophrenia: A Quantitative Review of the Evidence

Department of Psychology, York University, Toronto, Ontario, Canada.
Neuropsychology (Impact Factor: 3.27). 07/1998; 12(3):426-45. DOI: 10.1037/0894-4105.12.3.426
Source: PubMed

ABSTRACT The neurocognitive literature on test performance in schizophrenia is reviewed quantitatively. The authors report 22 mean effect sizes from 204 studies to index schizophrenia versus control differences in global and selective verbal memory, nonverbal memory, bilateral and unilateral motor performance, visual and auditory attention, general intelligence, spatial ability, executive function, language, and interhemispheric tactile-transfer test performance. Moderate to large raw effect sizes (d > .60) were obtained for all 22 neurocognitive test variables, and none of the associated confidence intervals included zero. The results indicate that schizophrenia is characterized by a broadly based cognitive impairment, with varying degrees of deficit in all ability domains measured by standard clinical tests.

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Available from: Walter Heinrichs, Apr 23, 2014
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    • "A previous study on long-term (3 years) cognitive performance in our First Episode Psychosis (FEP) sample showed that patients presented a worse evolution compared to controls in verbal and visual memory [53]. Moreover, a recent study on FEP [6] showed different course patterns of cognitive deficits among schizophrenia patients, thus supporting evidence for variability in the progression of neuropsychological deficits in schizophrenia [27]. underlie the functional connectivity of neural circuits involved in performance cognitive tasks [64]. "
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    ABSTRACT: Neurocognitive deficits are core symptoms of schizophrenia that determine a poorer outcome. High variability in the progression of neuropsychological deficits in schizophrenia has been described. It is still unknown whether genetic variations can affect the course of cognitive deficits. Variations in the Disrupted in Schizophrenia 1 (DISC1) gene have previously been associated with neurocognitive deficits. This study investigated the association between 3 DISC1 polymorphisms (rs6675281 (Leu607Phe), rs1000731, and rs821616 (Ser704Cys)) and long-term (3 years) cognitive performance. One-hundred-thirty-three Caucasian drug-naive patients experiencing a first episode of non-affective psychosis were genotyped. Cognitive function was assessed at baseline and after 3 years of initiating treatment. Other clinical and socio-demographic variables were recorded to eliminate potential confounding effects. Patients carrying the A allele of rs1000731 exhibited a significant improvement in Working Memory and Attention domains, and the homozygosity of the A allele of rs821616 showed a significant improvement in Motor Dexterity performance over 3 years of follow-up. In conclusion, DISC1 gene variations may affect the course of cognitive deficits found in patients suffering from the first episode of non-affective psychosis.
    European Psychiatry 09/2015; 30(7):861-867. DOI:10.1016/j.eurpsy.2015.07.007 · 3.44 Impact Factor
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    • "Schizophrenia is frequently accompanied by neuropsychological deficits which are spread across a wide range of cognitive functions ( Heinrichs and Zakzanis , 1998 ; Keefe and Harvey , 2012 ) . Memory and attention problems in concert with social cognitive impairments ( Fett et al . "
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    ABSTRACT: The majority of patients with schizophrenia display neurocognitive deficits (e.g. memory deficits) as well as inflated cognitive biases (e.g. jumping to conclusions). Both cognitive domains are implicated in the pathogenesis of the disorder and are known to compromise functional outcome. At present, there is a dearth of effective treatment options. A total of 90 patients with schizophrenia were recruited online (a diagnosis of schizophrenia had been confirmed in a large subgroup during a previous hospital admission). Subsequent to a baseline assessment encompassing psychopathology, self-reported cognition as well as objective memory and reasoning tests, patients were randomized to one of three conditions: standard cognitive remediation (mybraintraining), metacognition-augmented cognition remediation (CR) condition (variant of mybraintraining which encouraged patients to reduce speed of decision-making and attenuate response confidence when they made high-confidence judgements and hasty incorrect decisions) and a waitlist control group. Patients were retested after six weeks and again three months after the second assessment. Groups did not differ on psychopathology and neurocognitive parameters at any timepoint. However, at follow-up the metacognitive-augmented CR group displayed a significant reduction on jumping to conclusions and overconfidence. Treatment adherence correlated with a reduction of depression; gains in the training exercises from the standard mybraintraining condition were correlated with improved objective memory performance. The study suggests that metacognition-augmented CR may ameliorate cognitive biases but not neurocognition. The study ties in well with prior research showing that neurocognitive dysfunctions are rather resistant to change; the failure to detect significant improvement of CR or metacognition-augmented CR on psychopathology and neurocognition over time may partly be attributed to a number of methodological limitations of our s
    Frontiers in Psychology 07/2015; 6. DOI:10.3389/fpsyg.2015.01048 · 2.80 Impact Factor
    • "They concluded that even though the four executive functions were distinct constructs and differentially impaired in schizophrenia, this impairment partially reflected the influence of general cognitive factors, such as premorbid IQ and processing speed. Other authors have also suggested that executive function impairments are due to a global cognitive impairment present before the onset of psychotic illness and not to impairments in specific cognitive domains [17] [68]. "
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    ABSTRACT: Working memory deficits are considered nuclear deficits in psychotic disorders. However, research has not found a generalized impairment in all of the components of working memory. We aimed to assess the components of the Baddeley and Hitch working memory model: the temporary systems-the phonological loop, the visuospatial sketchpad and the episodic buffer (introduced later by Baddeley)-and the central executive system, which includes four executive functions: divided attention, updating, shifting and inhibition. We assessed working memory performance in a sample of 21 patients with a psychotic disorder and 21 healthy controls. Patients also underwent a clinical assessment. Both univariate and repeated measures ANOVAs were applied to analyze performance in the working memory components between groups. Patients with a psychotic disorder underperformed compared to the controls in all of the working memory tasks, but after controlling for age and premorbid IQ, we only found a difference in performance in the N-Back task. Repeated measures ANCOVAs showed that patients also underperformed compared to the controls in the Digit span test and the TMT task. Not all of the components of working memory were impaired in the patients. Specifically, patients' performance was impaired in the tasks selected to assess the phonological loop and the shifting executive function. Patients' also showed worse performance than controls in the N-Back task, representative of the updating executive function. However, we did not find higher impairment in the patients' performance respect to controls when increasing the loading of the task. Copyright © 2015. Published by Elsevier Inc.
    Comprehensive Psychiatry 05/2015; 61. DOI:10.1016/j.comppsych.2015.05.008 · 2.25 Impact Factor
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