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


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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    • "Patients with schizophrenia are characterized by cognitive deficits (Heinrichs and Zakzanis, 1998; Elvevåg and Goldberg, 2000). Specifically, previous research has shown that schizophrenia patients show deficits in a variety of cognitive domains, including attention, executive function and memory (Chan et al., 2004; Mesholam-Gately et al., 2009). "
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    ABSTRACT: Prospective memory (PM) refers to the ability to remember to perform intended actions in the future. Although PM deficits are a prominent impairment in schizophrenia, little is still known about the nature of PM in symptomatically remitted patients with schizophrenia. To address this issue, event-related brain potentials (ERPs) were recorded from 20 symptomatically remitted patients with schizophrenia and 20 healthy controls during an event-based PM paradigm. Behavioral results showed that symptomatically remitted patients with schizophrenia performed poorly on the PM task compared with healthy controls. On the neural level, the N300, a component of the ERPs related to PM cue detection, was reliable across these 2 groups, suggesting a degree of functional recovery of processes supporting cue detection in patients with symptomatically remitted schizophrenia. By contrast, the amplitude of the prospective positivity, a component of the ERPs related to PM intention retrieval, was significantly attenuated in symptomatically remitted schizophrenia patients relative to healthy controls. Furthermore, a significant positive correlation between the amplitude of the prospective positivity and accuracy on the PM task was found in those patients, indicating that patients’ poor performance on this task may result from the failure to recover PM cue-induced intention from memory. These results provide evidence for the existence of altered PM processing in patients with symptomatically remitted schizophrenia, which is characterized by a selective deficit in retrospective component (intention retrieval) of PM. Therefore, these findings shed new light on the neurophysiological processes underlying PM in schizophrenia patients during clinical remission.
    Frontiers in Behavioral Neuroscience 09/2016; 9:1-9. DOI:10.3389/fnbeh.2015.00262 · 3.27 Impact Factor
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    • "Single episodes are also encountered. In individual patients cognitive deficits may also vary, their severity may lie in a wide range from normal values [79] to a significant reduction [47] [74] [84]. "
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    ABSTRACT: Background Cognitive disturbances are widely pronounced in schizophrenia and schizophrenia spectrum disorders. Whilst cognitive deficits are well established in the prodromal phase and are known to deteriorate at the onset of schizophrenia, there is a certain discrepancy of findings regarding the cognitive alterations over the course of the illness. Methods We bring together the results of the longitudinal studies identified through PubMed which have covered more than 3 years follow-up and to reflect on the potential factors, such as sample characteristics and stage of the illness which may contribute to the various trajectories of cognitive changes. Results A summary of recent findings comprising the changes of the cognitive functioning in schizophrenia patients along the longitudinal course of the illness is provided. The potential approaches for addressing cognition in the course of schizophrenia are discussed. Conclusions Given the existing controversies on the course of cognitive changes in schizophrenia, differentiated approaches specifically focusing on the peculiarities of the clinical features and changes in specific cognitive domains could shed light on the trajectories of cognitive deficits in schizophrenia and spectrum disorders.
    European Psychiatry 11/2015; 30(8):1002-1010. DOI:10.1016/j.eurpsy.2015.08.005 · 3.44 Impact Factor
    • "Cognitive deficits are a prominent and stable feature of many patients with serious mental illness, and, in addition to mood and psychotic symptoms, account for high rates of disability and service utilization. Patients with schizophrenia average between one to three standard deviations below the mean of normal comparison subjects across a wide range of cognitive domains (Heinrichs and Zakzanis, 1998; Saykin et al., 1991). These cognitive deficits have been found to pre-date illness onset (Allen et al., 2003), thus suggesting impairment in cognition may be a core feature of the pathophysiology of the disorder irrespective of positive and negative symptoms typically attributed to illness severity. "
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    ABSTRACT: Objective: Deficits in cognitive functioning are related to functional disability in people with serious mental illness. Measures of functional capacity are commonly used as a proxy for functional disabilities for cognitive remediation programs, and robust linear relationships between functional capacity and cognitive deficits are frequently observed. This study aimed to determine whether a curvilinear relationship better approximates the association between cognitive functioning and functional capacity. Method: Two independent samples were studied. Study 1: participants with schizophrenia (n=435) and bipolar disorder (n=390) aged 18-83 completed a neuropsychological battery and a performance-based measure of functional capacity. Study 2: 205 participants with schizophrenia (age range=39-72) completed a brief neuropsychological screening battery and a performance-based measure of functional capacity. For both studies, linear and quadratic curve estimations were conducted with cognitive performance predicting functional capacity scores. Results: Significant linear and quadratic trends were observed for both studies. Study 1: in both the schizophrenia and bipolar participants, when cognitive composite z-scores were >0 (indicating normal to above normal performance), cognition was not related to functional capacity. Study 2: when neuropsychological screening battery z-scores were >-1 (indicating low average to average performance), cognition was not related to functional capacity. Conclusions: These results illustrate that in cognitively normal adults with serious mental illness, the relationship between cognitive function and functional capacity is relatively weak. These findings may aid clinicians and researchers determine who may optimally benefit from cognitive remediation programs, with greater benefits possibly being achieved for individuals with cognitive deficits relative to individuals with normal cognition.
    Schizophrenia Research 10/2015; DOI:10.1016/j.schres.2015.09.017 · 3.92 Impact Factor
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