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

The study of biochemical processes in schizophrenia has continued to be influenced by new knowledge in neurobiology and clinical nosology. With increasing frequency, neurobiology is taking clinical factors into account. Areas updated in the current review from this perspective include the dopamine hypothesis, monoamine oxidase research, post-mortem studies, endorphins, endogenous hallucinogens and drug-induced psychoses, immunological and viral factors, and serum creatine phosphokinase.
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PMID:Biochemical processes in schizophrenia: an update. 699 79

Six biological variables-platelet monoamine oxidase activity, urine phenylethylamine concentration, brain norepinephrine concentration, abnormalities on computerized tomography, lateralization asymmetries, and the presence or absence of tardive dyskinesia-are used to discriminate possible biological groups of schizophrenic patients. All variables successfully subclassify patients, some into divisions consistent with phenomological, psychosocial, or biochemical descriptions or hypotheses of schizophrenia. None of the measures, however, has sufficiently stood the test of time to be of clinical utility.
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PMID:The schizophrenia syndrome. Examples of biological tools for subclassification. 700 83

Genetic and biochemical findings in paranoid schizophrenia and other paranoid psychoses are reviewed. Although the data suggesting a lower genetic loading for schizophrenia in paranoid versus nonparanoid schizophrenia are unclear, paranoid schizophrenia does, to a limited extent, breed true within families. Monozygotic twins concordant for schizophrenia tend to be either both paranoid or both nonparanoid schizophrenics. In all studies, the risk for schizophrenia in the relatives of patients with paranoid psychosis is close to that found in the normal population. Genetic studies provide no evidence for a link between affective illness and either paranoid schizophrenia or paranoid psychosis. Although reports of low platelet monoamine oxidase activity in paranoid schizophrenia have not been confirmed, recent results suggest that brain norepinephrine levels may be higher in paranoid than in nonparanoid schizophrenics. Genetic and biochemical findings suggest some differences between paranoid and nonparanoid schizophrenia, but definitive clarification of the relationship between these two syndromes must await future research. From a genetic perspective, paranoid psychosis appears to bear little relationship to schizophrenia.
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PMID:The genetics and biochemistry of paranoid schizophrenia and other paranoid psychoses. 703 92

Smooth pursuit eye tracking impairment has been observed in the major psychoses, particularly schizophrenia. To understand better the relationship of smooth pursuit disruption to personality dispositions linked to psychiatric syndromes and to two other "marker variables" associated with psychosis (low platelet monoamine oxidase [MAO] activity and poor performance on the continuous performance task [CPT]), we studied the psychologic, biochemical, and psychophysiologic correlates of impaired smooth pursuit tracking in two nonpsychiatric patient populations. One sample consisted of 67 volunteers screened for extreme values in a distribution of platelet MAO activities, and the second included 29 volunteers screened for extreme scores on the CPT. An aggregate of about 5% of both samples showed clearly dysfunctional smooth pursuit. Eye tracking dysfunction did not seem to be related to either MAO or CPT performance in either study. Both studies were consistent in showing that subjects with impaired smooth pursuit eye tracking had a psychologic profile characterized particularly by social introversion.
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PMID:Smooth pursuit eye tracking impairment: relation to other 'markers' of schizophrenia and psychologic correlates. 711 10

Platelet monoamine oxidase (MAO) activity is significantly reduced in chronic schizophrenics with family history of schizophrenia. The degree of reduction is related to the extent of genetic load. Schizophrenics with no affected relatives do not differ from control subjects. These findings are consistent with the hypothesis of genetic heterogeneity in schizophrenia. Discrepancies among previously reported data sets can thus be explained by overrepresentation of nongenetic phenocopies with normal MAO levels. The implications for biologic and genetic research in schizophrenia are discussed.
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PMID:Platelet monoamine oxidase values and genetic heterogeneity in schizophrenia research. 726 44

Platelet MAO activity was assessed in 35 schizophrenics during a trial of the isomers of flupenthixol. Enzyme activity was unrelated to severity of symptoms, the presence of delusions, hallucinations or thought disorder or to negative symptoms. In a few patients MAO activity fluctuated widely with time, but in the group of patients on medication there was a slow decrease in enzyme activity which was significant after 28 days of treatment. Enzyme activity after 14 days' drug treatment was still correlated with activity before treatment, but after 28 days this significant correlation disappeared. Slow effects of neuroleptic drugs on platelet MAO activity may explain previous findings of reduced activity of the enzyme in schizophrenia.
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PMID:Platelet monoamine oxidase activity in acute schizophrenia: relationship to symptomatology and neuroleptic medication. 729 84

The authors compared platelet monoamine oxidase activity in schizophrenic patients and normal controls. A significant reduction in the enzyme activity was found in the male schizophrenic patients but not in the females. No differences were detected among the subgroups of schizophrenia. Sources of bias and the possible mechanism for the findings are discussed.
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PMID:Low platelet MAO activity and schizophrenia: sex differences. 731 98

A brief history and summary of studies designed to elucidate the role of monoamine oxidase (MAO) in schizophrenia are presented. The majority of these studies have reported a decrease in the platelet enzyme activity of chronic schizophrenic patients when compared to controls. Difficulties encountered when comparing MAO activity measured in different patient populations are also considered. Finally, the significance of decreased platelet MAO activity is discussed with respect to its possible etiological role in some forms of schizophrenia.
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PMID:Monoamine oxidase in schizophrenia: an overview. 737 51

This article summarizes findings from a series of studies that examined platelet monoamine oxidase (MAO) activity in patients with nonaffective schizophrenic disorders and schizophrenia-related depressions. The findings indicate that mean platelet MAO activity was not different from control values in the subgroup of nonaffective schizophrenic disorders without auditory hallucinations (that is, the S-1 subgroup). However, mean platelet MAO activity was reduced in the subgroup of nonaffective schizophrenic disorders characterized by the presence of auditory hallucinations often occurring in conjunction with paranoid features (that is, the S-2 subgroup). Moreover, we found that mean platelet MAO activity was increased in schizophrenia-related depressions characterized by histories of chronic asocial, eccentric, or bizarre behavior.
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PMID:Platelet monoamine oxidase activity in subgroups of schizophrenic disorders. 737 53

Platelets of healthy subjects and patients suffering from various disorders were assayed for their monoamine oxidase (MAO) activity and protein content. The latter tended to be lower with increasing platelet count. A linear correlation with negative slope between count and protein content was found to exist in platelets obtained from schizophrenic, parkinsonian, and (specific development) dyslexia patients. MAO activities appeared to vary significantly with respect to age and sex. In schizophrenic patients, a significant depression of MAO activity occurred which was more marked in chronic than in acute cases. Even larger activity reductions were seen in platelets of insulin-dependent diabetics while the MAO was enhanced in male dyslexic boys. When MAO activity was assessed with different substrates and methods, the results correlated well with each other. Small, but consistent discrepancies, however, arose in the schizophrenia data when compared with the control values.
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PMID:Protein content and monoamine oxidase activity in platelets. 737 59


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