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

We studied 18 never-mediated schizophrenic patients and 22 normal control subjects with 18F-deoxyglucose (FDG) positron emission tomography. Patients and controls performed the continuous performance test during FDG uptake. Cortical and subcortical structures comprising two circuits selected on the basis of several theoretical models of schizophrenia were examined. The correlation of glucose metabolic rate (GMR) for each structure in each circuit with connected structures was calculated and tested for two-tailed significance. Schizophrenics showed significantly different patterns of intercorrelations for both circuits. The largest difference was in the correlation of GMR in the anterior thalamus with the frontal cortex, a key element in the thalamo-cortical-striatal circuit suggested to be abnormal in some models of schizophrenia. Correlations of the frontal lobe with other regions were also more positive in normal controls than schizophrenics; controls had three correlational paths from the frontal cortex (to temporal cortex, ventral anterior thalamus, and dorsal medial thalamus) with significantly more positive correlations than schizophrenics perhaps consistent with other findings of frontal cortical dysfunction in schizophrenia. Normal controls also had both more significant positive and more significant negative correlations between the occipital cortex and other brain areas than schizophrenics. Correlations between homologous areas in the right and left hemispheres were prominent in both groups.
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PMID:Correlational patterns of cerebral glucose metabolism in never-medicated schizophrenics. 882 68

The FDG PET brain scans from 31 offenders with schizophrenia and schizoaffective disorder from a maximum security mental hospital were compared with those of normal controls (N = 6) in terms of relative FDG uptake in a range of regions covering frontal and temporal regions. The patient sample was divided into those who had a history of repetitive violent offending (RVO, N = 17) and those without a repetitive violent history (NRVO, N = 14) according to the violence rating of their pre-admission convictions. Reduced FDG uptake was noted at both the right and left anterior inferior temporal (R and L AIT) regions in NRVOs but only at LAIT in RVOs. NRVOs had significantly lower FDG uptake at RAIT than RVOs. The findings suggest that metabolic changes at AIT may be related to different patterns of violent offending in patients with schizophrenia.
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PMID:Positron emission tomography in male violent offenders with schizophrenia. 910 58

Previous research indicates that verbal learning and memory deficits are among the most severe cognitive deficits observed in schizophrenia. However, the concomitant patterns of regional brain function associated with these deficits in schizophrenia are not well understood. The present study examined verbal-memory performance and simultaneous relative glucose metabolic rates (rGMR) with FDG PET in 20 unmedicated schizophrenia patients who met stringent memory-performance criteria and 32 age- and sex-matched normal volunteers. On a modified version of the California Verbal Learning Test, patients recalled fewer correct words using a semantic-clustering strategy and exhibited more intrusions compared with normal subjects. However, patients had higher serial-ordering strategy scores, indicating their use of a less efficient organizational strategy. Among patients, greater use of the serial-ordering strategy was associated with decreased rGMR in frontal cortex and increased rGMR in temporal cortex. Patients had lower rGMR primarily in frontal and temporal cortex, but not parietal and occipital lobe regions. Patients also exhibited hypofrontality (lower ratio of frontal to occipital rGMR) compared with normal subjects. Among the patients, more severe hypofrontality was associated with increased perseveration errors.
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PMID:Hypofrontality in unmedicated schizophrenia patients studied with PET during performance of a serial verbal learning task. 1082 13

Permanent verbal, visual scenic and coenaestetic hallucinations are the most prominent psychopathological symptoms aside from psychomotor disorders in speech-sluggish catatonia, a subtype of chronic catatonic schizophrenia according to Karl Leonhard. These continuous hallucinations serve as an excellent paradigm for the investigation of the assumed functional disturbances of cortical circuits in schizophrenia. Data from positron emission tomography (F-18-FDG-PET and F-18-DOPA-PET) from three patients with this rare phenotype were available (two cases of simple speech-sluggish catatonia, one case of a combined speech-prompt/speech-sluggish subtype) and were compared with a control collective. During their permanent hallucinations, all catatonic patients showed a clear bitemporal hypometabolism in the F-18-FDG-PET. Both patients with the simple speech-sluggish catatonia showed an additional bilateral thalamic hypermetabolism and an additional bilateral hypometabolism of the frontal cortex, especially on the left side. In contrast, the patient with the combined speech-prompt/speech-sluggish catatonia showed a bilateral thalamic hypometabolism combined with a bifrontal cortical hypermetabolism. However, the left/right ratio of the frontal cortex also showed a lateralisation effect with a clear relative hypometabolism of the left frontal cortex. The F-18-DOPA-PET of both schizophrenic patients with simple speech-sluggish catatonia showed a normal F-18-DOPA storage in the striatum, whereas in the right putamen of the patient with the combined form a higher right/left ratio in F-DOPA storage was discernible, indicating an additional lateralized influence of the dopaminergic system in this subtype of chronic catatonic schizophrenia. Most likely, the prominent bitemporal F-18-FDG- hypometabolism in these chronic schizophrenic patients with speech-sluggish catatonia suffering from permanent continuous hallucinations, reflects a deficit in sensoric gating following prenatal cortical neurodevelopmental disturbances. However, the functional disturbances underlying hallucinations in "the schizophrenias" seem to be more complex; in different subtypes of the schizophrenic spectrum disorder hallucinations seem to be based on alterations in additional cortical and subcortical brain regions.
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PMID:Disturbed neural circuits in a subtype of chronic catatonic schizophrenia demonstrated by F-18-FDG-PET and F-18-DOPA-PET. 1147 18

Schizotypal personality disorder, a diagnosis defined partially in terms of a genetic relatedness to schizophrenia, has begun to receive extensive investigative study. While the exact etiologic relationship between schizotypal personality disorder and schizophrenia remains to be determined, three models have been considered: (1) the two may be distinct disorders, (2) they may be essentially identical disorders but expressed with different degrees of severity, or (3) they may be related disorders with a partially overlapping etiology that might account for the many similarities yet the lack of psychosis or severe deficits in schizotypal individuals. Some of the recent research in the structural and functional neuroanatomy, neurochemistry, cognitive function, and pharmacology of schizotypal personality disorder is reviewed with citation of the most recent findings from our laboratory and others. Both schizotypal and schizophrenic subjects appear to show abnormalities in temporal lobe volume, but schizotypal subjects do not appear to show the volumetric decreases in frontal cortex that schizophrenic patients evidence. Abnormalities in thalamic nuclei parallel these findings-the pulvinar, which projects to temporal association and sensory cortices, is reduced in both disorders, but the mediodorsal nucleus, which projects extensively to the frontal cortex, is reduced in schizophrenic patients but not in schizotypal patients. Functional imaging studies suggest that there may be abnormalities in frontal activation in both disorders, but that schizotypal individuals can recruit alternative regions to accomplish tasks requiring frontal lobe activation that may help compensate. Imaging studies of the subcortex including FDG/PET imaging of metabolic activity during a verbal learning task, SPECT imaging studies which measure binding of IBZM and its displacement following amphetamine administration, and plasma HVA determinations following 2-deoxyglucose administration all suggest the possibility of relatively reduced dopaminergic subcortical activity in schizotypal individuals compared to schizophrenic patients. Cognitive function is also impaired in the areas of working memory, verbal learning, and attention in schizotypal patients, as in schizophrenic patients, and they may be particularly susceptible to cognitive tasks with high context dependence, as in schizophrenia. Preliminary trials of catecholaminergic agents suggest that these agents may be able to improve these impaired cognitive functions.
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PMID:Cognitive and brain function in schizotypal personality disorder. 1185 90

We studied two subtypes of schizophrenia. the Kraepelinian subtype (n = 10) characterized by an unremitting and severe course and the non-Kraepelinian subtype (n = 17) characterized by a remitting course and some periods of self-care. Patients were assessed with positron emission tomography (PET) with 18F-deoxyglucose (FDG) and high-resolution magnetic resonance imaging (MRI). A group of 32 age- and sex-matched normal volunteers served as comparison subjects. During the FDG tracer uptake period, patients performed a serial verbal learning task. MR images were segmented into gray, white and cerebrospinal fluid regions, and warped to average normal coordinates. PET images were coregistered to the MR images and similarly warpedfor analysis. Kraepelinian subtype patients were characterized by lower metabolic rates in the temporal lobe and cingulategyrus. and lower fronto/occipital ratios than non-Kraepelinian subtype patients. Exploratory statistical probability mapping alsorevealed lower metabolic rates in the right striatum in Kraepelinian versus non-Kraepelinian patients. These differences couldnot be attributed to differences in age, symptom severity, task performance during FDG uptake, or severity of involuntary movements. Factor analysis of the cortical surface identified significantly lower temporal lobe metabolic rates in Kraepelinian patients than non-Kraepelinian patients. A combined frontal/temporal deficit or greater cortical change may be associated with poorer longitudinal course.
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PMID:Kraepelinian and non-Kraepelinian schizophrenia subgroup differences in cerebral metabolic rate. 1195 61

The concept of frontotemporal lobar degeneration comprises a heterogenous group of cortical dementias, including frontotemporal dementia, as the major clinical variant. Because of their highly variable clinical presentation, to establish the diagnosis of frontotemporal dementia could be a diagnostic challenge for the clinician. Here we report a 53 years old caucasian male patient who was admitted for hospitalization due to acute severe schizophrenia-like symptoms. The leading symptomatology comprised acoustic and bizarre optical hallucinations with euphoria and self-overestimation. Remission of the psychotic symptoms demasked the clinical picture of a rapidly progressive frontotemporal dementia with marked apathy, indifference, emotional blunting, loss of insight, change of personality and typical cognitive impairment. The diagnosis was supported by the results of cerebral MRI and FDG-18 PET. This first clinical manifestation of a schizophrenia-like syndrome in the 6 (th) life decade implicates frontotemporal dementia as an important differential diagnosis of schizophrenic disorders in late life. In addition of basically thinking about frontotemporal dementia, a detailed medical history, cognitive testing, neuroimaging and eventually the evaluation of the further disease course are necessary to establish a diagnosis of frontotemporal dementia.
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PMID:[Frontotemporal Dementia Presenting as Acute Late Onset Schizophrenia] 1313 Mar 43

The concept of frontotemporal lobar degeneration comprises a heterogenous group of cortical dementias, including frontotemporal dementia, as the major clinical variant. Because of their highly variable clinical presentation, to establish the diagnosis of frontotemporal dementia could be a diagnostic challenge for the clinician. Here we report a 53 years old caucasian male patient who was admitted for hospitalization due to acute severe schizophrenia-like symptoms. The leading symptomatology comprised acoustic and bizarre optical hallucinations with euphoria and self-overestimation. Remission of the psychotic symptoms demasked the clinical picture of a rapidly progressive frontotemporal dementia with marked apathy, indifference, emotional blunting, loss of insight, change of personality and typical cognitive impairment. The diagnosis was supported by the results of cerebral MRI and FDG-18 PET. This first clinical manifestation of a schizophrenia-like syndrome in the 6th life decade implicates frontotemporal dementia as an important differential diagnosis of schizophrenic disorders in late life. In addition of basically thinking about frontotemporal dementia, a detailed medical history, cognitive testing, neuroimaging and eventually the evaluation of the further disease course are necessary to establish a diagnosis of frontotemporal dementia.
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PMID:[A case of schizophreniform disorder in frontotemporal dementia (FTD)]. 1450 45

We report results of a FDG-PET study in 10 patients with schizophrenia (6 unmedicated, 4 never medicated) and 12 healthy age-matched controls. The patients met ICD-10 and DSM-IV criteria for schizophrenia and all reported psychotic, "positive" symptoms when tested. Schizophrenic patients had higher absolute CMRGlu values in almost all quantified regions compared to normal subjects. Using the occipital cortex as the reference region patients showed a hyperfrontal metabolic pattern. Other significant regional differences were found with respect to thalamus, striatum and temporal cortex. The finding of a hyperfrontality in un- and never medicated psychotic schizophrenic patients must be discussed in the light of the psychopathological symptoms of patients when tested, a possible disruption of cortico-striato-thalamic feedback loops and recent findings of a hyperfrontality in experimentally induced psychosis (ketamine- and psilocybin-model of schizophrenia).
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PMID:Hypermetabolic pattern in frontal cortex and other brain regions in unmedicated schizophrenia patients. Results from a FDG-PET study. 1583 58

Changes in glucose metabolism were studied in the brains of schizophrenic patients treated with neuroleptics, using [(18)F]fluoro-deoxy-glucose positron emission tomography (FDG-PET). Fourteen male and eight female patients in their thirties and forties were studied in a resting state. Data from FDG-PET were processed with an anatomic standardization method, three-dimensional stereotactic surface projections (3D-SSP), which provided relative glucose metabolic values that mitigated the contamination of brain atrophy. Z-score maps indicating metabolic differences between the patient and control groups were also acquired. Metabolic values in 19 regions were evaluated in the right and left hemispheres. Patients showed decreased values in the frontal cortex, primary sensory regions and anterior cingulate cortex, more in the rostral affective subdivision than the dorsal cognitive subdivision in both hemispheres, and increased metabolic values in left and right basal ganglia, left temporal and right medial parietal regions. Values were more decreased in both anterior cingulate regions, and more increased in the right thalamus in male than female patients, suggesting gender-related dysfunction in the anterior cingulate and thalamus in schizophrenia. FDG-PET demonstrated that schizophrenia may be a disorder with a dysfunction of fronto-striatal-thalamic circuitry including the cingulate cortex.
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PMID:Abnormal glucose metabolism in the anterior cingulate cortex in patients with schizophrenia. 1718 63


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