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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Executive functioning deficits have been identified in schizophrenics, their family members, in persons with schizophrenic spectrum disorders, and in others psychometrically at high risk for future psychosis. In the present study, a group hypothesized to be at high risk for future psychosis (Chapman and Chapman, 1985; Chapman et al., 1994) showed no generalized cognitive deficit, but demonstrated impairments on two executive functioning measures (Wisconsin Card Sorting Test and Stroop Color and Word Test) as compared to control students. Results suggest that executive function deficits, particularly impaired inhibitory control, appear in individuals who may be at risk of later decompensation into a psychotic state, and thus may be important in the pathogenesis of schizophrenia and schizophrenic spectrum disorders.
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PMID:Executive functioning deficits in hypothetically psychosis-prone college students. 937 92

Cognitive deficits in schizophrenia are reported to be more consistent with a static encephalopathy than a dementing disorder. This study investigates memory and intellectual decline in 62 chronic schizophrenic subjects using the Wechsler Adult Intelligence Scale-Revised (WAIS-R), the Rivermead Behavioural Memory Test and the National Adult Reading Test (NART) in a cross-sectional study using five age cohorts (18-29, 30-39, 40-49, 50-59 and 60-69 years of age) and then by two cohorts (young: 18-39; older: 40-69). A second method of investigating intellectual decline was implemented by estimating the discrepancy score between WAIS-R (current IQ) and NART (premorbid IQ) for each subject. No significant differences were found in WAIS-R Full Scale. Verbal and Performance IQ and memory functioning across the five age cohorts (and when using two age groups). A significant difference in test scores was found using the Picture Completion and Digit Symbol subtests of the WAIS-R. The differences were not related to age or duration of illness. No significant difference in scores were evident in the remaining WAIS-R subtests. These results support previous findings that schizophrenia is more consistent with a static encephalopathy than a dementing disorder and that intellectual and memory function does not markedly decline with age.
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PMID:Memory and intellectual deficits do not decline with age in schizophrenia. 937 33

Evidence has begun to accumulate which suggests that lack of awareness of illness in schizophrenia is related to and possibly the result of a cognitive deficit involving prefrontal cerebral dysfunction. This study further explores this relationship along with other domains of self-awareness in chronic schizophrenics and other subjects with serious mental disorders. One hundred eight schizophrenics and 21 bipolar subjects from three separate sites in Britain, Germany, and Canada were administered the Wisconsin Card Sorting Test and three measures of self-awareness. Lack of illness awareness and other domains of self-knowledge were significantly more related to poorer neuropsychological performance in schizophrenia patients than in the other subjects. The results support the hypothesis that lack of illness awareness is related to defective frontal lobe functioning as indexed by neuropsychological measures.
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PMID:Further parameters of insight and neuropsychological deficit in schizophrenia and other chronic mental disease. 945 46

This study was designed to determine whether patients with schizophrenia and those with affective disorders display a common pattern of cognitive deficits. Cognitive performance was assessed with a neuropsychological test battery in consecutively admitted in-patients with schizophrenia (n=100) and affective disorders (n=100). The two groups of patients showed a similar pattern of cognitive deficits, especially in tests focusing on attentional capacities. The groups only differed significantly in their performance on the Wisconsin Card Sorting Test (WCST), with the schizophrenic patients performing less well. These results suggest that, with the exception of the deficit as measured by the WCST, similar cognitive impairments exist in schizophrenia and affective disorders, even at very early stages of the illness. Therefore, patients with schizophrenia and those with affective disorders cannot be qualitatively distinguished with sufficient reliability. We postulate that the cognitive deficit pattern represents a final common pathway disorder in the two groups of patients.
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PMID:Cognitive deficits in schizophrenia and affective disorders: evidence for a final common pathway disorder. 961 Oct 85

Earlier efforts to localize the symptoms of schizophrenia in a single brain region have been replaced by models that postulate a disruption in parallel distributed or dynamic circuits. Based on empirical data derived from both magnetic resonance and positron emission tomography, we have developed a model that implicates connectivity among nodes located in prefrontal regions, the thalamic nuclei, and the cerebellum. A disruption in this circuitry produces "cognitive dysmetria," difficulty in prioritizing, processing, coordinating, and responding to information. This "poor mental coordination" is a fundamental cognitive deficit in schizophrenia and can account for its broad diversity of symptoms.
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PMID:"Cognitive dysmetria" as an integrative theory of schizophrenia: a dysfunction in cortical-subcortical-cerebellar circuitry? 961 21

Impairment of executive-frontal lobe functioning, affecting the planning, initiation and regulation of goal-directed behavior, is a common cognitive deficit in schizophrenia. However, it is unclear if deficits in these frontal-lobe-mediated abilities are differentially expressed across clinical subgroups. We analyzed executive-frontal abilities in relation to symptom expression in 53 hospitalized schizophrenic patients. Patients were assigned to one of three subgroups based on rank order analysis of Brief Psychiatric Rating Scale factors: Withdrawal-Retardation, Reality Distortion and Conceptual Disorganization. Executive-frontal tests included Visual Search, Verbal Fluency, Verbal Series Attention, Trail Making - Part B, Symbol Digit, Hopkins Verbal Learning, Digit Span, Wisconsin Card Sorting, Stroop Color-Word and Attentional Capacity. The schizophrenia group showed significant deficits relative to healthy control subjects (n = 20) on all tests. Exploratory factor analysis of test scores revealed three factors: (i) Verbal Processing/Memory; (ii) Cognitive Flexibility/Attention; and (iii) Psychomotor Speed/Visual Scanning. The three symptom subgroups were differentially impaired on executive-frontal abilities: Withdrawal-Retardation on psychomotor speed, verbal fluency, working memory, visual search and cognitive flexibility; Conceptual Disorganization on attention; Reality Distortion on verbal memory. The results have implications for syndrome definition, pharmacological intervention and prediction of outcome in schizophrenia.
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PMID:Executive-frontal lobe cognitive dysfunction in schizophrenia: a symptom subtype analysis. 970 52

Cognitive deficits are an integral feature of schizophrenia and have a deleterious effect on the ability of schizophrenic patients to work and function in a social environment. Drugs that bring about substantial cognitive improvement represent a major contribution in improving the quality of life in schizophrenia. Recent studies have suggested that the atypical antipsychotics may be more useful than conventional agents for improving cognition. There is evidence that scores on neuropsychological assessments have improved after treatment with clozapine, risperidone, and quetiapine. Future research is needed to characterize and quantify the cognitive effects of the atypical antipsychotics.
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PMID:Evaluating the effects of antipsychotics on cognition in schizophrenia. Collaborative Working Group on Clinical Trial Evaluations. 976 18

Cognitive impairment in schizophrenia must be seen as a disturbance of cortico-sub-cortical connectivity with a neurotransmitter imbalance in a circuitry system, which connects thalamic input with prefrontal processing and supplementary motor cortex and basal ganglia output. The concept of maze-solving behaviour as a continuous cognitive task evoking a conflict between prefrontal cortex and basal ganglia activity is explained and introduced to distinguish between the effects of D2 blocking agents and substances with a predominant 5HT2A receptor affinity, such as clozapine and risperidone. Complex mazes show a cognitive deficit in untreated schizophrenic patients that are impaired by conventional and improved by atypical antipsychotic substances. Processing speed improves most on clozapine, while parallel processing is best supported by the non-sedative atypical substance risperidone. Maze paradigms are presented.
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PMID:Cognitive dysfunction in schizophrenia: a new set of tools for the assessment of cognition and drug effects. 1022 41

Digital EEG (DEEG) and quantitative EEG (QEEG) are recently developed tools present in many clinical situations. Besides showing didactic and research utility, they may also have a clinical role. Although a considerable amount of scientific literature has been published related to QEEG, many controversies still subsist regarding its clinical utilization. Clinical applications are: 1. DEEG is already an established substitute for conventional EEG, representing a clear technical advance. 2. Certain QEEG techniques are an established addition to DEEG for: 2a) screening for epileptic spikes or seizures in long-term recordings; 2b) Operation room and intensive care unit EEG monitoring. 3. Certain QEEG techniques are considered possible useful additions to DEEG: 3a) topographic voltage and dipole analysis in epilepsy evaluations; 3b) frequency analysis in cerebrovascular disease and dementia, mostly when other tests have been inconclusive. 4. QEEG remains investigational for clinical use in postconcussion syndrome, learning disability, attention disorders, schizophrenia, depression, alcoholism and drug abuse. EEG brain mapping and other QEEG techniques should be clinically used only by physicians highly skilled in clinical EEG interpretation and as an adjunct to traditional EEG work.
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PMID:[Guidelines for recording/analyzing quantitative EEG and evoked potentials. Part II: Clinical aspects]. 1034 40

Cognitive deficits are a fundamental feature of the psychopathology of schizophrenia. Yet the effect of treatment on this dimension of the illness has been unclear. Atypical antipsychotic medications have been reported to reduce the neurocognitive impairment associated with schizophrenia. However, studies of the pattern and degree of cognitive improvement with these compounds have been methodologically limited and have produced variable results, and few findings have been replicated. To clarify our understanding of the effects of atypical antipsychotic drugs on neurocognitive deficits in patients with schizophrenia, we have (1) reported on newly established standards for research design in studies of treatment effects on cognitive function in schizophrenia, (2) reviewed the literature on this topic and determined the extent to which 15 studies on the effect of atypical antipsychotics met these standards, (3) performed a meta-analysis of the 15 studies, which suggested general cognitive enhancement with atypical antipsychotics, and (4) described the pharmacological profile of these agents and considered the pharmacological basis for their effects on neurocognition. Finally, we suggest directions for the development of new therapeutic strategies.
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PMID:The effects of atypical antipsychotic drugs on neurocognitive impairment in schizophrenia: a review and meta-analysis. 1041 27


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