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

There is new interest in subjective experiences of schizophrenia. This kind of analysis emphasizes the subjective stories of patients, and the methods do not pretend to have the objectivity of science. However, the plausibility and the empathetic resonance of the single case may bring subjective confirmation to the validity of an insight and indicate new directions of research. Following this line, the authors present a study of 3 single cases of 'reflexive' residual type of schizophrenia. The methods for selecting the cases and the philosophical groundings of the concept of 'reflexive schizophrenia' are explained. The analysis of the single cases revealed that (1) schizophrenic persons' cognitive deficit is related to the constitution of common sense; (2) some schizophrenics cope with the cognitive deficit by creating a theoretical corpus of axioms stemming from common sense, namely the 'axioms of everyday life'; (3) this mechanism of coping is described as an inflexible attachment to 'axioms of everydayness', and (4) this attachment to common sense releases the patient from all personal investment of self in the process of anchoring in the living world and, on this basis, allows a relatively solid, although distant, attachment to reality. The nature of deficit in schizophrenia is also discussed by confronting the phenomenological point of view and the neuropsychological, that is the so-called 'theory of mind'.
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PMID:Schizophrenia and common sense: study of 3 single cases. 1096 86

Cognitive deficits in schizophrenia have been associated with working memory problems. Schizophrenic patients (n = 24) and controls (n = 29) participated in simple short-term memory tasks, recalling a list of letters from the first to last item in the order of presentation. The authors hypothesized that deficient sequential representations would increase movement errors (e.g., ABCD being recalled as ABDC) or intrusion errors (e.g., ABCD being recalled as ABCX), whereas simple trace decay would lead to omission errors (e.g., ABCD being recalled as ABC_). Patients made disproportionately more omissions toward the end of 6-item lists. There were no group differences in movements or intrusions as a function of serial position. Schizophrenic patients' limited short-term memory span may be due to greater forgetting during recall and not to a selective deficit in the mechanisms responsible for maintaining serial order information.
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PMID:Short-term memory for serial order in schizophrenia: a detailed examination of error types. 1121 83

Latent inhibition (LI) reflects a cognitive process whereby repeated pre-exposure of a to-be-conditioned stimulus impairs subsequent conditioning. Since it is believed to reflect the ability of an organism to screen out irrelevant stimuli, disrupted LI has been suggested as a model for a cognitive deficit in schizophrenia. Animal studies have previously shown that indirect dopamine (DA) agonists can disrupt LI, an effect which is reversed by neuroleptics. Conversely, neuroleptics given alone potentiate LI. In this study, using pre-exposure to a tone stimulus which is subsequently paired with mild footshock, we have demonstrated that haloperidol given before conditioning only is equally as effective as haloperidol given twice, before pre-exposure and conditioning, in potentiating LI after 10 pre-exposures. This supports our earlier results with nicotine, pointing to conditioning as the critical time for the action of dopaminergic manipulations on LI. The implications for the use of potentiated LI as a screening test for neuroleptic action are discussed.
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PMID:Haloperidol potentiation of latent inhibition in rats: evidence for a critical role at conditioning rather than pre-exposure. 1122 85

Patients with schizophrenia exhibit an exceedingly wide range of symptoms from a variety of domains. The cardinal features are abnormal ideas (such as delusions); abnormal perceptions (such as hallucinations); formal thought disorder (as evidenced by disorganized speech); motor, volitional, and behavioral disorders; and emotional disorders (such as affective flattening or inappropriateness). In addition to these diverse, and sometimes bizarre symptoms, it has become increasingly apparent that the disorder is, to variable degrees, accompanied by a broad spectrum of cognitive impairments. This review addresses the question of whether the cognitive deficits seen in schizophrenic patients are the core features of the disorder. In other words, we explore whether schizophrenia is best characterized by symptoms or cognitive deficits (we suggest the latter) and moreover, whether there is a specific cognitive deficit profile that may assist in diagnosis. First, we discuss what the cognitive deficits are. Then we address in turn the reality, frequency, predictive validity, specificity, course and susceptibility to neuroleptic effects of these cognitive impairments. In brief, we argue that various cognitive deficits are enduring features of the schizophrenia illness, that they are not state-related and are not specific to subtypes of the illness, and, more specifically, that working memory and attention are characteristically impaired in patients with schizophrenia, irrespective of their level of intelligence. Last, we conclude that problems in these cognitive domains are at the very core of the dysfunction in this disease.
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PMID:Cognitive impairment in schizophrenia is the core of the disorder. 1125 53

According to a widespread theory, the first-rank symptoms such as delusions of control or thought insertion met in schizophrenia result from a failure in predicting the consequences of an action on the basis of a forward model based of the intended motor commands (efference copy). This assumption of an impairment in the central monitoring of their own actions is inferred from experiments showing that it is more difficult for schizophrenic patients than for controls to correct erroneous movements in the absence of visual feedback. In our study, 19 schizophrenic patients (10 with Schneiderian symptoms and nine without) and 19 paired control subjects were subjected to a sensorimotor adjustment task to reassess this hypothesis. We show that the patients who succeeded the task not differently from the control subjects were those who were aware of the manual correction (n = 9). Surprisingly, most of them presented Schneiderian symptoms. This suggests that the experience of alien control observed in certain schizophrenic patients cannot be directly related to an underlying cognitive deficit in the conscious monitoring of their own actions.
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PMID:Self-monitoring in schizophrenia revisited. 1133 92

There exists considerable evidence implicating the alpha (alpha) adrenergic system in the superior therapeutic effects of clozapine for the treatment of schizophrenia, as also its associated adverse hypersalivation side effect. It would seem plausible for variants of the adrenoceptors to be associated with the clozapine response. The present study tested the hypothesis that a biallelic polymorphism in the promoter region of the alpha2a-adrenoceptor gene confers susceptibility to schizophrenia, and is associated with a clozapine-induced (favorable) therapeutic response and/or a clozapine-induced hypersalivation. Ninety-seven treatment-resistant schizophrenic patients were assessed using the Brief Psychiatric Rating Scale before and after clozapine treatment. The results of clozapine treatment demonstrated that the alpha2a-adrenoceptor gene variants did not play a major role in the susceptibility, hypersalivation adverse effect or clozapine response of patients with schizophrenia. The polymorphism of the alpha2a-adrenoceptor gene investigated is not likely to play a major role in the pathogenesis of schizophrenic disorders or clozapine response, although the hypothesis that these genes are implicated in the cognitive deficit and polydipsia associated with schizophrenic disorders may, however, still warrant further study.
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PMID:Association analysis of polymorphism in the promoter region of the alpha2a-adrenoceptor gene with schizophrenia and clozapine response. 1134 63

Cognitive deficits have been hypothesized to be differentially related to the negative, positive and disorganization dimensions of schizophrenia symptoms. In this article, we quantitatively review the published literature on the relationships between symptom dimensions in schizophrenia and performance on the two most widely applied tests of executive functioning and sustained attention, the Wisconsin Card Sorting Test (WCST) and the Continuous Performance Test (CPT). Meta-analyses were conducted on studies that reported correlational data for the relations between performance on these tests and scales of positive and negative symptoms. The more recent distinction between disorganization and reality distortion was also taken into account. The results showed statistically significant relationships of negative symptoms with worse performance on the WCST and the CPT. Disorganization symptoms showed a significant positive correlation with perseverations on the WCST, but not with CPT performance. In contrast, reality distortion symptoms and general scores for all positive symptoms did not correlate with either measure. Although some correlations were statistically significant, the observed associations between psychiatric symptoms and cognitive performance were typically weak, suggesting relative independence of these disease processes.
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PMID:Relationship between symptom dimensions and neurocognitive functioning in schizophrenia: a meta-analysis of WCST and CPT studies. Wisconsin Card Sorting Test. Continuous Performance Test. 1137 41

Learning the association between one stimulus (a condition stimulus, CS) and another (unconditioned stimulus, US) can be impaired by prior exposure to the CS alone--latent inhibition (LI). Current theories attempting to elucidate the cognitive deficit in schizophrenia have used the abolition of LI in schizophrenia as an indicator of attentional dysfunction. However, it has always been unclear if human and animal LI are measuring the same psychological processes. It is obviously important to clarify this relationship so that theoretical and experimental developments in the rat do not mislead the investigation of brain-behaviour relationships in schizophrenia. LI in the rat is strongly dependent upon context. Our aim was to examine the context specificity of LI in humans and specifically to: (1) investigate whether participants' belief that they are in a different context is sufficient to abolish LI, even though there is no physical change in the environment; (2) produce a context manipulation that is immune to alternative interpretation in terms of stimulus generalization decrement; and (3) investigate whether a "tonic" change of context reduces or abolishes human LI, thus complementing previous reports using a "phasic" change of context. In two experiments we manipulated context in either the real world or a virtual world, and showed that LI is abolished by a change of context in adult humans.
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PMID:Context dependent latent inhibition in adult humans. 1154 13

Cognitive deficits have come to be viewed as a hallmark feature of schizophrenic illness. Although laboratory based assessment of patients' cognitive deficits has been well investigated, few studies to date have examined the utility of clinical ratings of cognitive symptoms using the Schedule for the Assessment of Negative Symptoms (SANS) attention subscale. In this report, we examined the convergence between clinical ratings of cognitive impairment using the SANS attention subscale and performance on a variety of neurocognitive tests designed to measure attentional impairment, as well as other cognitive constructs such as working memory and executive functioning. A total of 56 acute schizophrenic inpatients were clinically rated with the SANS and completed the Continuous Performance Test, Digit Span Distraction Test, Wisconsin Card Sorting Task, and the Trailmaking Test. A series of correlational and regression analyses were conducted to test the concurrent and discriminant validity of the SANS attention subscale. Performance measures of attention, but not working memory or executive functioning, were significantly correlated with and moderately predicted the severity of SANS rated inattention. Additionally, the attention subscale was discriminated from the other SANS negative symptom subscales in predicting a laboratory measure of attentional functioning. The SANS attention subscale demonstrated both concurrent and discriminant validity. These data indicate that attentional dysfunction in schizophrenia can be meaningfully rated and interpreted using the SANS.
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PMID:Convergent validity and neuropsychological correlates of the schedule for the assessment of negative symptoms (SANS) attention subscale. 1158 9

Cognitive deficits have been viewed as being characteristic features of schizophrenia. Neuropsychological impairment has been also identified in depression and mania. Recent studies have suggested that patients with bipolar disorder do not make full recovery between episodes of illness and that neuropsychological dysfunction may persist beyond these episodes. Remitted bipolar patients performed worse on Wisconsin Card Sorting Test, Verbal fluency and Stroop Test than healthy controls, the results of the patients with affective disorders with psychotic features were comparable with those of schizophrenics. Some studies suggest an association between the course of illness and the intensity of cognitive deficits, this link was not confirmed in other reports. Imaging studies have shown the presence of white matter lesions and other abnormalities in the brains of bipolar patients. The relative reduction in cerebral tissue may contribute to neuropsychological impairment in subgroup of bipolar patients. Results of studies on the role of white matter lesions are inconsistent. Recent studies point to an association between decreased prefrontal cortex volume and cognitive disturbances. Attention is focused on hippocampus volume as well, since it is associated with cognitive deficits in bipolar disorder. Further studies are needed to elucidate whether a severe course of illness is associated with more pronounced cognitive disorders and whether presence of psychotic symptoms during the acute phase of the illness is a predictor of the occurrence of cognitive deficits in patients with bipolar affective disorder.
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PMID:[Cognitive deficits in the bipolar affective disorder]. 1176 Apr 65


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