Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypofrontality (hypometabolism and hypoperfusion) has been demonstrated in patients with schizophrenia by the use of several imaging methods, such as positron emission tomography (PET). In this study, Tc-99m hexamethylpropylene amineoxime (HMPAO) and SPECT were used to investigate regional blood flow changes in 20 schizophrenic patients (12 males and 8 females, aged 15-50 years) experiencing acoustic hallucinations. Tc-99m HM-PAO (15-20 mCi) was injected intravenously, eight regions/hemisphere were drawn on transaxial sections, and tracer redistribution was calculated for each region. Frontal/occipital ratios (0.917 +/- 0.045) and frontal/whole-slice ratios (0.984 +/- 0.036) were determined for each patient. The patients had significantly lower frontal/occipital ratios (P less than 0.0005) and lower frontal/whole-slice ratios (P less than 0.01) in comparison to a normal group (11 cases).
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PMID:Tc-99m HMPAO/SPECT determination of regional cerebral blood flow changes in schizophrenics. 227 33

The present study compared the performance on apraxia tests and additional motor tasks between medicated chronic schizophrenic inpatients (n = 21) and healthy subjects (n = 21). Praxis testing did not reveal a clear-cut apractic syndrome in the patient group. The most striking difference between patients and healthy controls was the more frequent use of body parts as object (BPO) by schizophrenic patients (P < 0.0003). There was no significant difference in psychopathology between subgroups classified according to their BPO performance, although a tendency towards a difference in duration of illness and the actual hospitalization period existed between BPO subgroups. Schizophrenic patients performed more poorly than controls in frontal motor tasks: sequencing, including oral sequential movements, and reciprocal innervation. Frontal motor task performance tended to be related to the negative dimension of schizophrenia in accordance with previous studies. The data do not support the assumption that BPO performance is part of a multidimensional concrete attitude in schizophrenic patients. Nevertheless, this peculiarity in motor behaviour might be a link between neurophysiology and psychopathological phenomenology in schizophrenia. We therefore suggest further investigation focusing the performance of object-related pantomime movements in schizophrenic patients.
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PMID:Investigation of gestural and pantomime performance in chronic schizophrenic inpatients. 794 55

Frontal and occipital lobe width were determined in the computed tomographic (= CT) scans of 135 schizophrenic patients, 158 neuropsychiatrically healthy and 102 psychiatric control subjects, including patients with affective psychosis, neurosis and schizoaffective psychosis. Most healthy right handed subjects demonstrate a relative enlargement of the right frontal as well as left occipital lobe compared to the opposite hemisphere. These normal frontal and occipital lobe asymmetries were selectively reduced in schizophrenics (f.: 5%, p < .0005; o.: 3%, p < .05), irrespective of the psychopathological subgroup. Schizophrenic neuroleptic non-responders revealed a significant reduction of frontal lobe asymmetry (3%, p < .05), while no correlation between BPRS-subscores and disturbed cerebral laterality could be detected. In sum the present study demonstrates disturbed cerebral lateralisation in schizophrenic patients supporting the hypothesis of interrupted early brain development in schizophrenia.
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PMID:Reduced frontal and occipital lobe asymmetry on the CT-scans of schizophrenic patients. Its specificity and clinical significance. 857 8

1. Tardive dyskinesia is more important in postmenopausal women than men of comparable age and a peak of first episodes of schizophrenia is observed in postmenopausal women. The effect of ovariectomy (2 weeks or 3 months) in rats was investigated as a model of decreased gonadal function associated with menopause. 2. Frontal cortex D1 receptor density and affinity were similar in intact male compared to intact female rats and progressively decreased in density with time after ovariectomy, with no change of affinity. Striatal D1 and D2 receptors also decreased in density after ovariectomy for both receptor subtypes, with no change of affinity. Striatal D1 receptor density and affinity were similar in intact male and female rats, whereas the density of D2 receptors was higher in females. Treatment with estradiol for 2 weeks restored the D2 but not the D1 receptor changes. 3. In the substantia nigra pars reticulata, striatum, nucleus accumbens, and entopeduncular nucleus, a progressive increase in [3H]flunitrazepam specific binding associated with GABAA receptors was observed as a function of time following ovariectomy; this was corrected with estradiol treatment. In contrast, the opposite was observed for [3H] flunitrazepam binding in the globus pallidus, where ovariectomy decreased binding, which was corrected with estradiol replacement therapy. 4. Low prefrontal cortex dopamine activity with implications of D1 receptors in negative symptoms of schizophrenia is hypothesized. Furthermore, GABAergic overactivity in the internal globus pallidus-substantia nigra pars reticulata complex is hypothesized in tardive dyskinesia. 5. The present data suggest that gonadal hormone withdrawal by reducing brain dopamine receptors and producing an imbalance of GABAA receptors in the output pathways of the striatum may predispose to schizophrenia and dyskinesia.
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PMID:The modulation of brain dopamine and GABAA receptors by estradiol: a clue for CNS changes occurring at menopause. 874 69

The prevalence of abnormal subjective experiences is high in schizophrenic patients. This study starts from the hypothesis that these subjective disorders are associated with cognitive disturbances. In order to test this hypothesis a study was carried out on 40 patients who were diagnosed as suffering from schizophrenia according to RDC and DSM-III-R criteria. They were consecutively admitted due to a recrudescence of their symptomatology. Version 3 of the Frankfurt Complaint Questionnaire, adapted for Spanish by the authors, was used as an instrument for the assessment of subjective experiences. Eight patients refused to answer the questionnaire. A neuropsychological battery, including the Mini-Mental State, some subtests from the WAIS, Bender's visual-motor test, Rey's Complex Figure, and the Trail Making Test, was used. Frontal neurological signs were evaluated. The abnormal subjective experiences of schizophrenics presented a close association with neuropsychological disturbances and, to a lesser degree, of intensity with frontal neurological signs. Regression analyses by means of stepwise method and partial correlation analyses were undertaken. Many significant relationships between subjective experiences and cognitive disturbances persisted after controlling the influence of age, gender, education, lack of insight, neuroleptic doses, and biperidene doses.
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PMID:Abnormal subjective experiences in schizophrenia: its relationships with neuropsychological disturbances and frontal signs. 906 5

In an our recent preliminary study, we reported the neuropsychological finding of a double dissociation in the frontal lobe functioning between 25 OCD patients and 25 schizophrenics. The first group performed normally in the Wisconsin Card Sorting Test (WCST), which is considered sensitive to Dorso-Lateral Prefrontal Cortex (DLPFC) dysfunctions and abnormally to the Object Alternation Test (OAT), which has been proposed as a tool sensitive to Orbito-Frontal Cortex (OFC); on the other hand, schizophrenics performed abnormally to the WCST and normally to the OAT. The present study, conducted on a new sample of 60 schizophrenic in-patients, 60 OCD in-patients and 30 normal subjects, matched according to age, educational level, handedness and duration of illness, confirms our preliminary data and it suggests a more selective impairment of OFC system in OCD and of DLPFC in schizophrenia. Moreover, schizophrenic patients with paranoid subtype showed worse WCST performance compared to non-paranoid subtype. Our results could open some interesting perspectives about the neuroanatomical systems involved in these two major psychiatric illnesses and so, about their pharmacological treatment, on the basis of the prominent catecholaminergic characterization of the DLPFC and, respectively, the cholinergic innervation of the OFC.
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PMID:The selective breakdown of frontal functions in patients with obsessive-compulsive disorder and in patients with schizophrenia: a double dissociation experimental finding. 920 94

Between warning signal (S1) and imperative signal (S2), the EEG shifts negatively (contingent negative variation, CNV) reflecting preparation and expectancy. Reduced CNV and continued negativity after S2 (post-imperative negative variation, PINV) have been repeatedly found in schizophrenic patients and have been interpreted as a deficit in attentional processes (CNV) and as uncertainty about the correctness of one's own response to the S2 (PINV). Recent studies obtained a CNV reduction specifically at central sites but not at frontal ones. The present study investigated whether these alterations of slow negative potentials depend on present state of symptoms, on the particular task used, and on neuroleptic medication. Therefore, out-patients and in-patients were studied, two different S1-S2 tasks were used, and the control groups were healthy subjects and patients with Parkinson's disease. The central CNV reduction was stable across tasks and across in-patients and outpatients. Frontal CNV was reduced in in-patients but in only one of the two tasks in outpatients. The schizophrenic patients' enhanced PINV was larger contralaterally than ipsilaterally to the responding hand, correlated with medication, and occurred in similar way in patients with Parkinson's disease. Thus, the PINV increase might reflect the Parkinsonian side effects of the anti-psychotic medication. In contrast, the central CNV reduction appears as a stable marker of schizophrenia, the frontal CNV reduction as a state-dependent effect. The central CNV reduction might reflect impairment in forming stable stimulus-response associations, the relative frontal enhancement might reflect the out-patients' attempt at compensating that impairment.
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PMID:Slow EEG potentials (contingent negative variation and post-imperative negative variation) in schizophrenia: their association to the present state and to Parkinsonian medication effects. 1042 84

We investigated the relationship between the P300, neuropsychological test performance and symptomatology in recent-onset schizophrenic patients (n = 45) to gain insight into underlying mechanisms of abnormal P300 in schizophrenia. The P300 was recorded in two sessions with an intermission of five minutes, at the midline frontal, central and parietal electrode site. P300 amplitude and latency were compared with those obtained in 25 controls. Twenty patients were treated with olanzapine and 19 patients with risperidone. P300 amplitude was smaller and latency longer in patients than in controls. In the patient group, parietal P300 amplitude reduction was related to poorer performance on neuropsychological tests of memory. Frontal P300 amplitude reduction was related to impaired selective attention. In patients with negative symptomatology, P300 amplitude was reduced in the second P300 session compared with the first. Patients on risperidone demonstrated a smaller parietal P300 amplitude than patients using olanzapine. Reduced parietal P300 amplitude could signify a dysfunction in the continuous memory updating of current events. Negative symptomatology may be associated with a time dependent decrease in neuronal firing, as indicated by reduced P300 amplitude in the second P300 session.
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PMID:Clinical and neuropsychological correlates of the P300 in schizophrenia. 1195 70

Frontal-subcortical circuits form the principal network, which mediate motor activity and behavior in humans. Five parallel frontal-subcortical circuits link the specific areas of the frontal cortex to the striatum, basal ganglia and thalamus. These frontal-subcortical circuits originate from the supplementary motor area, frontal eye field, dorsolateral prefrontal region, lateral orbitofrontal region and anterior cingulate portion of the frontal cortex. The open afferent and efferent connections to the frontal-subcortical circuits mediate coordination between functionally similar areas of the brain. Specific chemoarchitecture and multiple neurotransmitter interactions modulate the functional activity of each circuit. Dorsolateral prefrontal circuit lesions cause executive dysfunction, orbitofrontal circuit lesions lead to personality changes characterized by disinhibition and anterior cingulate circuit lesions present with apathy. The neurobiological correlates of neuropsychiatric disorders including depression, obsessive-compulsive disorder, schizophrenia and substance abuse, imply involvement of frontal-subcortical circuits.
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PMID:Frontal-subcortical neuronal circuits and clinical neuropsychiatry: an update. 1216 39

Rats with excitotoxic neonatal ventral hippocampal lesions (NVHL) manifest in early adulthood a variety of behavioral and neurochemical abnormalities mimicking those seen in patients with schizophrenia. Some of these aberrations implicate malfunction of the midbrain dopamine systems. We studied NVHL effects on dopamine release in the rat frontal cortex, nucleus accumbens, and striatum during acute stress caused by inescapable continuous footshock (0.45 mA). Serum total corticosterone and prolactin levels were used as peripheral indices of stress. As an indirect index of dopamine release, tissue 3-methoxytyramine levels attained in vivo 10 min after monoamine oxidase inhibition was assayed in rats sacrificed by instantaneous microwave fixation of the brain tissue. Nonshocked NVHL rats showed significantly less nucleus accumbens' 3-methoxytyramine accumulation than their sham counterparts. Frontal cortical 3-methoxytyramine levels rose similarly after 20-min footshock in both groups of rats, but while it normalized after 60-min footshock in the sham rats, it did not decrease in the NVHL rats. Nucleus accumbens' 3-methoxytyramine was significantly elevated after either 20-min or 60-min footshock in both groups, whereas striatal 3-methoxytyramine was significantly elevated in the NVHL rats only. Serum corticosterone showed similar elevations in the sham and NVHL rats, but the patterns differed in that there was no attenuation after 60-min footshock in the latter. The lesion did not affect serum prolactin response. These data indicate that neonatal ventral hippocampal damage enhances and prolongs certain neural and neuroendocrine responses to acute physical stressor(s), and thus may affect adaptation and enhance detrimental effects of stress.
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PMID:Neonatal ventral hippocampal damage modifies serum corticosterone and dopamine release responses to acute footshock in adult Sprague-Dawley rats. 1253


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