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

Alpha rhythm is classically described as a bilateral posterior rhythm of substantially constant frequency in the range of 8-13 Hz which is enhanced by mental relaxation and blocked by attention. Since the full expression of alpha rhythm has been shown to occur coincident with puberty, it is possible that the establishment of alpha rhythm is subject to neuroendocrine influences which govern psychosexual maturation. There is ample evidence to indicate that the pineal gland is implicated in cerebral maturation and psychosexual development. Nocturnal plasma melatonin levels have been shown to decline progressively throughout childhood reaching a nadir at puberty. Since administration of melatonin has been reported to block alpha rhythm, it is proposed that the progressive decline in melatonin secretion during childhood facilitates the maturation of the alpha rhythm. Consequently, the presence of alpha rhythm could be used as a neurophysiological marker for the activity of the pineal gland and disorders associated with absent or delayed maturation of the alpha rhythm such as autism, dyslexia, personality disorders, epilepsy, Tourette's syndrome, and schizophrenia might be related to disturbances of pineal melatonin functions in early life. Moreover, since the EEG patterns associated with cerebral immaturity (i.e., slowing, absence of alpha activity) are more pronounced in the left hemisphere, this hypothesis implies differential influence of the pineal gland on hemispheric maturation potentially accounting for the vulnerability of the left hemisphere to cerebral insults.
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PMID:Alpha rhythm and the pineal gland. 130 57

The results of many studies using quantitative EEG techniques in clinical settings have been published. Those reports are reviewed here, with emphasis on those that used EEG frequency analysis and topographic mapping. In cerebrovascular disease, these methods can confirm the existence of lesions that are too mild to show up on routine EEG or too mild or too early to show up on computed tomography. The results correlate well with cerebral blood flow studies. These EEG tests can be done continuously in an intensive care unit or operating room. However, exact localization ability is inferior to that seen using traditional neuroimaging tests. In epilepsy, quantitative EEG techniques have found subtle degrees of background EEG changes near epileptic foci. Other methods can quantify epileptic spikes in useful ways and can indicate which region is driving other regions during seizures. Quantification is also useful for measuring drug effects when drugs (such as thiopental) are given deliberately to provoke acute EEG changes. Other measurements of drug effects may become useful in the future. In patients with mass lesions and metabolic encephalopathies, quantitative EEG changes do occur, and some of these correlate with the clinical state. However, in the latter settings, the clinical advantages for patient care are not yet clear, especially in comparison to available neuro-imaging studies and other routine medical tests. For dementia, quantitative EEG techniques are being developed. Some of these tests are accurate in moderately or severely demented patients, but there is still poor accuracy for early or borderline cases. For dyslexia, schizophrenia, and depression, there is a considerable volume of research reports but still no consensus about how to use quantitative EEG tests for care of individual patients. These tests require substantial user expertise in EEG. At present, these tests should be viewed as adjunctive to traditional EEG testing: such routine EEG testing should serve as the foundation for any clinical use of quantitative EEG tools.
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PMID:Quantitative EEG: II. Frequency analysis and topographic mapping in clinical settings. 307 70

The hypothesis is advanced that certain psychoses in adults devolve from attention deficit disorder (ADD), which has a fundamental impact on cognitive and social development and thus affects personality structure and psychodynamics. This 'ADD psychosis' often masquerades as schizophrenia or an affective disorder and hence is frequently misdiagnosed, precluding appropriate clinical intervention. Based upon clinical evidence and empirical research involving phenomenological comparisons, premorbid history, high risk studies, neurodiagnostic evaluations, and pharmacotherapeutic response, it is suggested that ADD psychosis in adults be regarded as a separate diagnostic entity. Distinguishing symptomatology, anamnesis, family history, therapeutics, as well as prognosis, are discussed. The concept of attention deficit disorder (ADD), until recently referred to as minimal brain dysfunction (MBD), has been conceived as a childhood affliction with rather specific and circumscribed manifestations. The diverse features which embrace this syndrome, such as hyperactivity and dyslexia, were first identified and subsumed under the collective banner of MBD about 2 decades ago. The complex hypotheses concerning its possible etiology have been detailed elsewhere and need not be repeated here. Rutter, based on his extensive literature review and seminal studies, has come to regard MBD as a subclinical brain disorder developing from a genetically determined biochemical abnormality, which produces symptoms of hyperactivity, impulsivity, attention deficit, aggressivity, and conduct disturbance. Indeed, factor analytic studies reviewed by Rutter support the co-occurrence of these pathological features in children, yet the empirical evidence for a distinct syndrome and for a precise etiology has been admittedly weak, with some contending that MBD or ADD is simply a catch-all for disparate neurological symptoms of unknown and variable pathogenesis.
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PMID:Attention deficit disorder psychosis as a diagnostic category. 345 65

The impression that the prevalence of mental disorder has been increasing during the last decades is only partially justified. The considerable increase in the demand for psychiatric and psychotherapeutic help is influenced by quite a number of factors that vary in nature and direction. The most essential contribution was made by changes in the age composition of the population - and here primarily by the growing number of mentally ill elderly persons - and by the enormous increase in life expectancy. In milder psychiatric disorder the increase in the utilization of medical help is mainly due to new ways of treatment and to the great enlargement of psychiatric and psychotherapeutic services in most industrial countries, for which the zeitgeist of transition from a predominance of natural science to a more psychological understanding of life forms the background. Civilizational factors in a closer sense, like the raising of the achievement level for school beginners or alterations in the threshold of tolerance between mental illness needing medical intervention and mental suffering to be borne with submission to God's will, play an essential role particularly for the widening of the disease concept and thus for changes in the frequency of certain deficits of achievement and feeling, such as 'reading disorder' or depressive states. The fact that the age-corrected risk of falling ill with schizophrenia has remained stable over many decades - wherever it could be investigated - does not point to a relation with variable environmental factors like industrialization, civilization or social order. In contrast with this disease in a closer sense, the rates of psychiatrically relevant forms of deviant behaviour - suicidal attempts, drug- and alcohol-related disorders - show rapidly changing upward and downward variations. Thus, they are more comparable to criminality rates that vary over time and culture. There is obviously a relation between changes in the frequency of deviant behaviour and changing patterns of values in society, such as the reduction of educational intensity and the commitment of adolescents to norms and convictions of their parents. This is why the most distinct changes in these rates occur at the age most accessible to contemporary or fashionable influences: in youth and younger adult age. Except for age-related changes, we do not seem to have become more ill than the generation of our parents, but more pessimistic.
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PMID:Are mental disorders increasing over time? 405 92

Abnormalities of functional connection between specialized areas in the human brain may underlie the symptoms which constitute the schizophrenia syndrome. Callosal and intrahemispheric fibres may be equally involved. The clinical emergence of symptoms in the later stages of brain maturation may be dependent on myelination of these fibre groups, both of which have extended myelination cycles. Ontogenetically earlier variants of the same mechanism could theoretically result in dyslexia and the syndromes of Kanner and Gilles de la Tourette. As new and unique extensions of specialized function emerge within the evolving brain, biological trial and error of connection both within and between them may produce individuals possessing phylogenetically advanced abilities, or equally, others possessing a wide range of abnormalities including those which comprise the schizophrenia syndrome. A dormant phenotypic potential for schizophrenia may exist in individuals who never develop symptoms during the course of a lifetime though some of these may become clinically apparent under the influence of various precipitating factors. It is concluded that abnormal functional connection and its normal and "supernormal" counterparts may be natural, essential, and inevitable consequences of brain evolution, and that this may have been so throughout the history of vertebrate brain evolution.
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PMID:Schizophrenia, abnormal connection, and brain evolution. 687 13

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

For some time it has been known through the results of family, twin, and adoption studies that heredity appears to play a significant causal role in many mental disorders, including schizophrenia, bipolar disorder, and other mood disorders, Alzheimer's Disease, panic disorder, obsessive compulsive disorder, autism, dyslexia, and Tourette's Syndrome. The precise patterns of inheritance of these complex disorders have not been determined, nor have the relevant genes been localized or cloned. Because the genetics are complex and because there is also clearly an environmental contribution to behavior, we expect the analysis of the genetics of mental illness to be arduous, and not quickly resolved. There are several compelling reasons to continue to focus our attention on uncovering the genetic factors for severe mental illness. Prominent among these are the implications for better treatment of mental disorders. The National Institute of Mental Health supports a wide range of studies on psychiatric genetic research.
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PMID:Psychiatric genetic research at the National Institute of Mental Health. 772 97

Approximately 5% of 8-10-year-olds experience exceptional difficulties learning to read (developmental dyslexia). This usually has a congenital basis; it runs in families, and affects 4 times as many boys as girls. Dyslexics typically show impairment both in phonemic segmentation (the subdivision of speech beyond the natural syllabic level) and in sequencing small visual symbols. Both these skills draw upon the ability of the nervous system to time sensory events precisely. A specific magnocellular cell type which expresses a distinctive surface antigen plays a crucial role in these functions. The development of this cell line is probably congenitally impaired in dyslexics. Visually they have lowered flicker and motion sensitivity, and disorder of the magnocellular layers of the Lateral Geniculate Nucleus can be seen post mortem. Likewise they have lowered sensitivity to changes in frequency and amplitude of sounds, hence impaired discrimination of speech sounds. These disorders are associated with abnormal hemispheric lateralisation in these subjects, e.g. dyslexics show reduction or reversal of the usual left > right asymmetry of the planum temporale. Many of these characteristics of impaired magnocellular function and reversed hemispheric asymmetry are found not only in dyslexic children but also in developmental dysphasics, autistics, high schizotypes and schizophrenics. I will speculate therefore that normal magnocellular development promotes normal hemispheric asymmetry and that impaired magnocellular development is responsible for a spectrum of problems associated with impaired hemispheric specialisation, ranging from the mildest, dyslexia, to the most severe, schizophrenia.
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PMID:Developmental dyslexia, neural timing and hemispheric lateralisation. 777 21

In an earlier study, adult dyslexia was found to be strongly associated with positive schizotypal traits, and particularly with unusual perceptual experiences. However, recent evidence suggests that the structure of psychosis-proneness in normals may involve three or four distinct yet related dimensions. Therefore a further study was conducted, using a wider range of measures, to explore associations between dyslexia and these different syndromes of psychosis-proneness. Relationships with handedness were also investigated. If three syndromes of psychosis-proneness were delineated, broadly corresponding to "Active", "Withdrawn" and "Schneiderian/Unreality" syndromes of schizophrenia, dyslexics showed elevations on both positive syndromes (Active and Unreality), but not on the negative, Withdrawn syndrome. With a four-factor model only one dimension, perceptual/cognitive anomalies, distinguished dyslexics from controls. These findings confirm an association between dyslexia and positive, but not negative, schizotypal traits. Mixed-handedness was strongly associated with dyslexia, and in controls with those measures of psychosis-proneness involving unusual perceptual experiences. This suggests that reduced lateralization may be a feature common to both dyslexia and the Unreality syndrome of schizotypy, which may help to account for the strong relationship between them.
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PMID:Dyslexia, handedness and syndromes of psychosis-proneness. 777 22

Schizophrenia has been hypothesized to be associated with an underlying brain developmental anomaly, specifically affecting normal brain asymmetries. The most pronounced asymmetries are present on the superior surface of the temporal lobes, the left plane, as measured along the sylvian fissure (planum temporale) being longer than the right in the majority of normal individuals. These asymmetries encompass Wernicke's area, the anatomical substrate for language, and have been found to be less pronounced in individuals with developmental language problems, i.e. dyslexia. Since disordered language is one of the hallmarks of schizophrenia, the present study focuses on the planum temporale and related superior temporal gyrus. Eighty-five first-episode schizophrenic patients and 40 controls had measurements of the sylvian fissure taken from coronal slices. The pattern of asymmetry in controls was for the right length to be longer than the left in anterior slices, and for left to be longer than right in posterior slices (corresponding to the planum temporale). Schizophrenic patients as a group demonstrated less asymmetry (R > L) in anterior slices, and female patients showed a trend for less (L > R) asymmetry in posterior slices. In contrast to the report of Barta et al. (1990), the volume of the anterior superior temporal gyrus did not differ from controls in first-episode schizophrenic patients. Neither the presence of formal thought disorder nor auditory hallucinations defined a subgroup of patients with reduced size or lateralization of the planum temporal or superior temporal gyrus.
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PMID:Asymmetries in the superior temporal lobe in male and female first-episode schizophrenic patients: measures of the planum temporale and superior temporal gyrus by MRI. 801 82


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