Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

P300 is often, but not always, observed to be more reduced over left than right temporal lobes in patients with schizophrenia. The possibility that task differences contribute to the inconsistency in the literature was explored in this study. ERPs were collected from 17 right-handed men with schizophrenia (DSM-IIIR) and 11 right-handed healthy male community controls, performing three auditory oddball tasks - respond to a target tone by: (1) counting; (2) pressing a response button with the right index finger; or (3) pressing a response button with the left index finger. Although patients with schizophrenia had smaller and later P300 amplitudes than controls, they did not have smaller P300s over the left temporal scalp (T3) than over the right (T4). P300 recorded over the left (C3) and right (C4) motor cortices indicated sensitivity to responding hand, with greater negativity being associated with contralateral button pressing. Failure to find P300 asymmetry is not related to the presence or absence of a button pressing task, or the hand used for button pressing. Rather, P300 asymmetry may be related to structural neuroanatomical asymmetries.
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PMID:Left temporal deficit of P300 in patients with schizophrenia: effects of task. 1102 95

Previous studies have revealed various abnormalities in late-component ERP amplitude and latency in schizophrenia, considered as a diagnostic category. The aim of this study was to investigate the within-sample associations between late-component ERPs and three primary syndromes of schizophrenia Reality Distortion, Psychomotor Poverty and Disorganisation. Subjects included 40 schizophrenics and 40 age and sex matched nonpsychiatric controls. Auditory ERPs (N100, N200, P200, P300) were elicited using an auditory oddball paradigm. Between-group analyses of target data showed reduced N100, N200 and P300 amplitude, increased P200 amplitude and delayed N200 latency in schizophrenics compared to controls. For non-target data, schizophrenics showed similarly reduced N100 amplitude and delayed N200 latency. Within-group analyses of target data showed that the three syndromes (determined by principal component analysis of PANSS ratings) were differentiated by ERP latency, but not amplitude (Disorganisation delayed left hemisphere P200 and P300 latency; Reality Distortion earlier global, midline and left hemisphere N200 latency; Psychomotor Poverty delayed posterior N100 latency). Notably, only Disorganisation showed a divergent pattern of associations with non-target ERP data: reduced P200 amplitude and delayed N100 latency.
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PMID:Late component ERPs are associated with three syndromes in schizophrenia. 1106 45

P300 auditory evoked potentials were recorded in 27 schizophrenic patients in the standard oddball paradigm. P300 amplitude in the right frontal zone correlated positively with the age of the patients at the onset of disease. As compared with normal (18 subjects), schizophrenics showed both smaller P300 amplitudes and longer latencies. The findings are assumed to reflect impairment of information processing in schizophrenia. It is emphasized that the level of impairment is higher when the disease occurs in adolescence.
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PMID:[P300 auditory evoked potentials in schizophrenia]. 1124 88

In order to examine the effects of risperidone on cognitive impairment in schizophrenia, event-related potentials (ERPs) were recorded before and after switching from conventional neuroleptics to risperidone in schizophrenic patients. ERPs were recorded during two auditory discrimination tasks (an oddball task and a distraction task) in 10 medicated schizophrenic patients during conventional neuroleptic and risperidone treatments. The amplitudes and latencies of N 100 and P300 component were measured in ERPs for target stimuli in the oddball task and in ERPs for target and novel stimuli in the distraction task. Although N 100 amplitude and latency and P 300 amplitude did not change significantly after switching the drug compared to that during conventional neuroleptic treatment, P 300 latency for target stimuli shortened significantly during risperidone treatment in both tasks, accompanied by the shortening of the reaction time in the distraction task. The P 300 latency change did not correlate with the change of the severity of psychopathology. These findings suggest that risperidone may speed the information processing in schizophrenic patients, contributing to the improvement of cognitive functions.
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PMID:Effects of risperidone on event-related potentials in schizophrenic patients. 1130 67

Functional abnormalities in the interhemispheric transfer via the corpus callosum in schizophrenia may result in filtering problems and information processing problems, which may in turn be related to the synchronization of cortical event-related activity. To explore whether a relationship exists between corpus callosum (CC) size, measured with in-vivo magnetic resonance imaging, and late auditory event-related P300 potentials, 50 patients with schizophrenia as well as 50 healthy controls were examined. The absolute CC size and subregional areas, as well as the CC areas adjusted for total brain volume, were not significantly different between patients with schizophrenia and controls. While no significant group differences were observed for P3a-, P3b-, PSW-amplitudes and P3b-latencies, P3a- and PSW-latencies were significantly prolonged for patients with schizophrenia. Absolute CC total size was significantly correlated with P3b-amplitudes in healthy controls (r=0.29; P=0.044). In patients with schizophrenia, significant correlations were observed between the subregion of the posterior body of the CC and positive slow wave (PSW; r=0.47; P=0.001). P3a-, P3b- and PSW-latencies were not significantly correlated to CC size in either patients with schizophrenia or healthy controls. The results are discussed in terms of the possibility that abnormalities in interhemispheric transfer may underlie the mechanisms of schizophrenia.
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PMID:Corpus callosum and P300 in schizophrenia. 1134 70

The existence of neurodegeneration is a debated issue in schizophrenia research. The P300 component of event-related electrical potentials (ERP) has been related to the different degree of damage to gray and white matter. This study explores the possible relationship between P300 amplitude and/or latency and the existence of degenerative processes in schizophrenia, by assessing its correlation with volume of sulcal CSF and duration of illness, as transversal indicators of neurodegeneration. Nineteen patients (14 males, 5 females) and 13 controls (6 males, 7 females) were studied with MRI and electrophysiological records (P300). The possible influence of sex and age at the time of the exploration was statistically controlled in both groups. The results show a significant negative correlation between P300 amplitude and prefrontal CSF volume in the patient group. A lower though still significant correlation was also found between P300 amplitude and duration of illness, whereas no correlation was found in the control group. These results support the hypothesis that P300 amplitude may be interpreted as a marker of neurodegeneration in schizophrenia.
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PMID:P300 amplitude as a possible correlate of frontal degeneration in schizophrenia. 1134 71

The auditory P300 is affected by arousal and emotion. We examined the effect of drawings expressing sadness or pleasure on auditory event-related potentials (ERP) during recovery from schizophrenia. Oddball-paradigm auditory ERP were recorded while presenting one of these drawings to nine patients with paranoid schizophrenia and seven patients with other types of schizophrenia during the acute stage and again during remission. P300 parameters (amplitude, area, and latency), reaction time, and symptom scores were evaluated. P300 amplitude and area were significantly greater in the recovery than in the acute phase. Increases were larger when viewing drawings that expressed sadness than when viewing drawings that expressed pleasure. In paranoid-type patients, P300 when viewing pleasurable drawings was similar to that when viewing sad drawings during the acute phase; in remission, P300 was significantly larger when viewing sad drawings than when viewing pleasurable drawings. In non-paranoid patients, P300 while viewing pleasurable drawings was significantly larger than that while viewing sad drawings during the acute phase; this difference disappeared during recovery. P300 latency and reaction time were not influenced by facial-affect stimuli or recovery. A significant negative correlation was noted between amplitude and negative symptom scores. P300 amplitude and area may be useful state markers during recovery in schizophrenic patients. Effects involving attention resources and emotional arousal are also involved.
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PMID:Changes in auditory P300 with clinical remission in schizophrenia: effects of facial-affect stimuli. 1144 85

A family with a (1;11)(q42;q14.3) translocation significantly linked to a clinical phenotype that includes schizophrenia and affective disorders is described. This translocation generates a LOD score of 3.6 when the disease phenotype is restricted to schizophrenia, of 4.5 when the disease phenotype is restricted to affective disorders, of 7.1 when relatives with recurrent major depression, with bipolar disorder, or with schizophrenia are all classed as affected. This evidence for linkage is among the strongest reported for a psychiatric disorder. Family members showed no distinctive features by which the psychiatric phenotype could be distinguished from unrelated cases of either schizophrenia or affective disorders, and no physical, neurological, or dysmorphic conditions co-occurred with psychiatric symptoms. Translocation carriers and noncarriers had the same mean intelligence quotient. Translocation carriers were similar to subjects with schizophrenia and different from noncarriers and controls, in showing a significant reduction in the amplitude of the P300 event-related potential (ERP). Furthermore, P300 amplitude reduction and latency prolongation were measured in some carriers of the translocation who had no psychiatric symptoms-a pattern found in other families with multiple members with schizophrenia, in which amplitude of and latency of P300 appear to be trait markers of risk. The results of karyotypic, clinical, and ERP investigations of this family suggest that the recently described genes DISC1 and DISC2, which are directly disrupted by the breakpoint on chromosome 1, may have a role in the development of a disease phenotype that includes schizophrenia as well as unipolar and bipolar affective disorders.
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PMID:Schizophrenia and affective disorders--cosegregation with a translocation at chromosome 1q42 that directly disrupts brain-expressed genes: clinical and P300 findings in a family. 1144 44

Biological, phenomenological and cognitive similarities are known to exist between schizophrenia and schizotypal personality disorder (SPD). This study examined whether, and to what extent, abnormalities in event-related potentials (ERPs) already extensively reported in schizophrenia can also be observed in persons psychometrically identified with SPD. Event-related potentials were examined in nine SPD subjects and nine controls recruited from among 1693 college students, using the Schizotypal Personality Questionnaire (SPQ) and the Structured Clinical Interview for DSM-III-R (SCID I and II). Event-related potentials were recorded during an auditory oddball task. Smaller P300 amplitude and prolonged P300 latency were found in SPD subjects as compared with controls. Our findings indicate that such individuals do have deficits in information processing similar to that found in schizophrenia. We can conclude that P300 abnormalities may not be specific for SPD but that abnormalities shown in SPD are possibly a vulnerability marker for developing schizophrenia.
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PMID:Abnormalities of auditory event-related potentials in students with schizotypal personality disorder. 1155 39

P300 event-related brain potential (ERP) amplitude is smaller in patients with schizophrenia compared to unaffected controls, but whether left temporal component amplitude is also smaller is debated. The present study employed meta-analytical methods to quantitatively assess previous P300 schizophrenia asymmetry findings. All P300 articles on schizophrenia using an auditory oddball paradigm published before January 2000 were obtained by comprehensive literature searches and cross-referencing for related articles. A total of 19 original articles reporting complete midline electrode data and 11 articles reporting lateral asymmetry electrode data were reviewed, which included different independent conditions that yielded 50 independent data sets. P300 amplitude differences between patients with schizophrenia and control subjects from the midline electrodes yielded effect sizes that differed among recording sites, such that Fz was significantly smaller than Pz, with Cz effect sizes smaller than Pz but larger than Fz. Comparison of P300 amplitude from the lateral data for the T3 and T4 electrodes found no reliable effect size difference when these electrodes were analyzed separately. However, comparison of P300 amplitude effect sizes from the TCP1 was significantly larger than that from the TCP2 when these electrodes were analyzed separately. P300 amplitude is smaller overall in patients with schizophrenia compared to control subjects and differs in its effect size topography across the midline and temporal electrode sites, with the strongest effect sizes obtained for the Pz midline and TCP1 lateral electrodes.
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PMID:P300 asymmetry in schizophrenia: a meta-analysis. 1160 Jan 90


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