Sight and insight: regional cerebral metabolic activity in schizophrenia visualized by positron emission tomography, and competing neurodevelopmental perspectives

Article Abstract:

Modern imaging technologies have become sophisticated enough in recent years to visualize metabolic activity in certain areas of the brain. However, both the findings and their interpretation raise as many questions as they answer. This is especially true of imaging of neural activity in the brains of schizophrenics, where conflicting results from small studies have led to conflicting hypotheses. For example, in the earliest brain studies using positron emission tomography (PET), normal cerebral activity was found to be greatest in the frontal cortex, decreasing toward the back of the brain, while in schizophrenics, the increased frontal activity was reduced. More recent studies, however, have revealed hyperactivity of the frontal region in schizophrenics. All existing studies may have methodological problems, such as not controlling for the effects of neuroleptic (antipsychotic) drugs in the interpretation of results. Nevertheless, one conclusion that may be drawn is that the frontal region of the brain is 'hyperinnervated' in schizophrenics, meaning that there is excessive transmission of nerve signals as a result of abnormal neural development in that region. While new imaging techniques are very powerful, they have not yet been used in enough studies that control for such variables as regional cerebral blood flow, medication status, patient characteristics, or test conditions. On the basis of the studies that do exist, the hypothesis that schizophrenia is a neurodevelopmental disorder receives some support. (Consumer Summary produced by Reliance Medical Information, Inc.)

Usage, Brain, PET imaging, Positron emission tomography

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The lifetime outcome and involuntary movements of schizophrenia never treated with neuroleptic drugs: four rare cases in Ireland

Article Abstract:

There has been interest in the natural history and long-term outcome of schizophrenia, but there is little opportunity to study cases that have not been treated with medication. Four such cases were found in Ireland, as well as a fifth case in which medication was used only very briefly. Each patient has shown symptoms of schizophrenia over the years but had never been treated because the widespread use of medication for schizophrenia did not begin in Ireland until these patients were in their 70s and no longer exhibiting severe psychotic symptoms. All exhibited continued signs sufficient for diagnosis with schizophrenia, however, and three of the five exhibited mild orofacial movements such as involuntary grimacing. All had marked cognitive impairment such as disorientation to time, place, and person. The findings suggest that, left untreated, schizophrenics continue to exhibit symptoms throughout the natural course of their life, although the symptoms may change over time. Psychotic symptoms such as hallucinations were not found. The primary symptoms were cognitive impairment and involuntary facial movements, as well as a range of other symptoms appropriate to the particular subtype of schizophrenia that was diagnosed. Interestingly, involuntary facial movements seen in some schizophrenics today are thought to be a side effect of treatment with neuroleptic medication. While it is possible that this is true, the movements may also be an effect of long-term schizophrenic illness. (Consumer Summary produced by Reliance Medical Information, Inc.)

Care and treatment, Evaluation, Development and progression, Face, Movement disorders, Symptomatology, Signs and symptoms

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Schizophrenia: a neuropathological perspective

Article Abstract:

Schizophrenia, unlike dementia, is commonly viewed as a substantially functional disease (i.e. due to confused thought as opposed to organic causes) despite evidence of at least a partially physiological basis. Research into what organic components may be present has produced conflicting, if not controversial, results, and more careful research design is warranted. Recently, there have been consistent findings that schizophrenics have significantly less brain weight than do matched controls. The average is nearly five percent less in mass. There also seem to be corresponding differences in brain length and volume It is not known how these differences might have occurred, and what specific effects they have on the functioning of the individual. Compared with brains of Alzheimer's patients, the structural changes in the brains of schizophrenics are less pronounced. Research has shown the relations of cognitive impairment and premorbid functioning with loss of brain weight, decrease in size, and other abnormalities. It is suggested that schizophrenics have a developmental abnormality of the medial temporal lobe which, due to disruption in its ability to process incoming information properly, causes what we know to be the characteristic symptoms of thought disorder seen in schizophrenics. It is speculated that this abnormality is genetic, but its nature remains little known. (Consumer Summary produced by Reliance Medical Information, Inc.)

Nervous system diseases

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