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

Confusion may exist between the reliability of a binary rating (for example, schizophrenia versus not-schizophrenia) and its implications for validity. High reliability does not guarantee validity, but paradoxically, low reliability does not imply poor validity in all contexts. Changes in the base rate or in experimental design may indicate high validity even when the reliability was thought to be low. Attempts to improve the psychiatric nomenclature by increasing only reliability run the risk of the "attenuation paradox" where further increases in reliability will make the ratings less valid. Finally, the assumption of random error in making diagnoses does not always hold, so that statistical analyses must be adjusted accordingly. New statistical methods are needed to index only false-positive or false-negative rates in order to quantify the error that will reduce some validity coefficients.
Arch Gen Psychiatry 1978 Dec
PMID:Reliability and validity in binary ratings: areas of common misunderstanding in diagnosis and symptom ratings. 72 82

Paranoid symptoms were found in 40% of patients admitted to a university general hospital psychiatric unit during a ten-month period. Fifty-eight percent of this group had frank paranoid delusions, while the rest had ideas of reference or generalized suspiciousness. Only one half of those who had paranoid delusions had paranoid schizophrenia. A significant number had affective disorders or organic brain disorder. Ideas of reference and suspiciousness were found in many patients who were not psychotic. The therapeutic implications of these findings are reported in three patients who were inadequately treated for affective disorders because the presence of paranoid symptomatology had led to an incorrect diagnosis of schizophrenia.
Arch Gen Psychiatry 1978 Mar
PMID:Paranoid symptoms in patients on a general hospital psychiatric unit. Implications for diagnosis and treatment. 72 91

The ability of six different operational definitions of schizophrenia to identify prospectively patients whose eventual prognosis would be poor was studied using data from a six-year follow-up of a series of 134 patients with functional psychoses. All six definitions were more successful at predicting a poor symptomatic outcome than a poor social outcome. Spitzer's Research Diagnostic Criteria, Carpenter's flexible criteria, and Langfeldt's criteria predicted a poor outcome as well as the original clinical diagnoses and were considerably better than the New Haven criteria, Schneider's first rank symptoms, or the computer program Catego.
Arch Gen Psychiatry 1979 Jan
PMID:Prognostic implications of six alternative definitions of schizophrenia. 76 Jun 95

Methylphenidate hydrochloride dextroamphetamine sulfate, and levamfetamine succinate have potential as pharmacologic tools for the indirect evaluation of the role of neurotransmitters in schizophrenia. In actively ill schizophrenic patients, methylphenidate administered intravenously causes a brief but clear intensification of preexisting psychotic symptoms, such as hallucinations and delusions. In our study, methylphenidate, dextroamphetamine, and levamfetamine were administered in equimolar doses to schizophrenic patients. Methylphenidate was a more effective activator of symptoms than dextroamphetamine, which in turn was more effective than levamfetamine. Levodopa (L-dopa) given orally also reportedly produces a temporary worsening of schizophrenic symptoms. While these findings augment a body of information suggesting that dopamine and norepinephrine may play a role in the activation of schizophrenic symptoms, our findings with methylphenidate (reportedly weak in eliciting stereotyped behaviour in rat) and our review of the literature indicate complexities that remain to be resolved. There is some utility of the procedure for differential diagnosis and selective therapy, but this is still of occasional and limited potential.
Arch Gen Psychiatry 1976 Mar
PMID:Methylphenidate, dextroamphetamine, and levamfetamine. Effects on schizophrenic symptoms. 76 22

Four patients with chronic schizophrenia of stationary character were studied in order to titrate the lowest dose of thioridazine necessary for symptomatic control when the drug is given in combination with the inhibitor of catecholamine synthesis, metyrosine. The study showed 15% to 50% of the pretrial dose level of thioridazine hydrochloride was effective. In the present trial, the 779704 combination was maintained without any alterations in dosage for six months, and the therapeutic effect persisted unchanged. This treatment period was terminated by a double-blind crossover design, and the activity of metyrosine was corroborated in all cases. Plasma drug concentrations and cerebrospinal fluid amine metabolites were measured. The data indicate that schizophrenic symptoms can be profoundly influenced by changes in catecholamine synthesis. Catecholamine-carrying neurons thus seem to be fundamentally involved in those brain functions that are disturbed in schizophrenia. The clinical usefulness of metyrosine in combination with neuroleptic agents deserves more extensive investigation.
Arch Gen Psychiatry 1976 Apr
PMID:Potentiation by metyrosine of thioridazine effects in chronic schizophrenics. A long-term trial using double-blind crossover technique. 77 4

The classification of functional psychoses has traditionally been dichotomous with schizophrenia and manic-depressive disorder, which are considered separate entities. However, the psychiatric literature is replete with descriptions of psychoses with mixed features. A variety of names has been applied to these psychoses, including the term "schizo-affective." Confusion exists regarding the nature of these psychoses, much of it resulting from a tendency to limit investigation to an acute view of symptom complexes. This article examines the schizo-affective states across a variety of dimensions, including the acute symptomatologic picture, response to lithium carbonate therapy, follow-up studies, family history, and genetics. While the term "schizo-affective," as commonly used, probably describes a heterogeneous group of psychoses, considerable evidence supports the hypothesis that at least a subgroup of these psychoses has a definite relationship to the major affective disorders.
Arch Gen Psychiatry 1976 Oct
PMID:Schizo-affective psychosis: fact or fiction? A survey of the literature. 78 71

Platelet monoamine oxidase (MAO) activity was investigated in a series of 60 patients with chronic schizophrenic illnesses free from neuroleptic medication, and 70 normal controls. No significant differences in platelet MAO activity or in substrate preference were detected between patients and controls, using tryptamine and tyramine as substrates. Platelet MAO activity did not distinguish patients with positive symptoms from those with negative symptoms alone and did not show any relationship with severity of disease or with a number of clinical features. These findings suggest that low platelet MAO activity cannot be regarded as a genetic marker for schizophrenia. Important determinants of platelet MAO activity yet to be discovered may have contributed to the discrepancies in recent observations of platelet MAO activity in schizophrenia.
Arch Gen Psychiatry 1976 Nov
PMID:Platelet monamine oxidase in schizophrenia. An investigation in drug-free chronic hospitalized patients. 79 Nov 82

Among the evidence supporting the dopamine hypothesis of schizophrenia is the finding that both amphetamine and methylphenidate hydrochloride, potent releasers of dopamine, can cause exacerbation of symptoms in the acute schizophrenic patient. The present report describes three experiments in which the effects of amphetamine in chronic schizophrenic patients were studied. In one of the experiments, orally administered, daily doses of 20 mg of dextroamphetamine sulfate given at 8 PM had little or no effect on the sleep duration of the subjects. In the other two experiments, doses up to 40 mg given orally also had little or no effect on the performance of the subjects on a variety of behavioral tests. There was no evidence of an exacerbation of the disease process in any of the subjects. The most consistent amphetamine effect was a dose-related increase in blood pressure. These results indicate that the chronic schizophrenic patient may be hyporesponsive to amphetamine and suggest that if the dopamine hypothesis is correct, then it must be modified to take into account these findings in the chronic patient.
Arch Gen Psychiatry 1976 Dec
PMID:Hyporesponsivity of chronic schizophrenic patients to dextroamphetamine. 79 62

To provide data on several issues related to disordered thinking in schizophrenia, 200 acutely ill psychiatric patients (including 55 schizophrenics) were evaluated on four instruments to assess thought pathology (the Object Sorting Test, the Rorschach Test, a social comprehension test, and a proverbs test). Patients were assessed at two phases of their disorders (the acute phase and the phase of partial recovery). The results suggest (1) disordered thinking is not unique to schizophrenia; (2) distinctions between mild and severe levels of thought pathology are important; and (3) disordered thinking is influenced by acute psychopathology and acute upset. Inferential evidence suggests (4) disordered thinking fits along a continuum with normal thinking; (5) "thought disorders" are not a discrete, separate entity, standing apart from other aspects of thinking; and (6) older concepts about primary symptoms in schizophrenia need reexamination.
Arch Gen Psychiatry 1977 Jan
PMID:Is disordered thinking unique to schizophrenia? 83 25

Disordered, very short-term memory (VSTM) has been hypothesized as the fundamental cognitive deficit in schizophrenia. We describe a method that measures VSTM using self-stimulated auditory average evoked potentials. This paradigm allows the VSTM hyothesis to be tested relatively free of superficial attentional and motivational artifacts. The experimental results are consistent with a VSTM dysfunction in schizophrenia. Very short-term memory dysfunction is discussed in light of recent blink reflex evidence that there is a short time constant information processing system with a time base similar to VSTM (ie, 1 to 1,000 msec). This leads to new testable hypotheses about information processing and VSTM in schizophrenia. It also lays the basis for interpreting this phenomenon as a pathologic exaggeration of an adaptive neurophysiologic mechanism.
Arch Gen Psychiatry 1977 Jan
PMID:Very short-term memory dysfunction in schizophrenia. Defective short time constant information processing in schizophrenia. 83 26


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