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)

It has been noted that the term "schizophrenia" is now applied to a group in many ways dissimilar to Emil Kraepelin's cases of dementia praecox and Eugene Bleuler's of schizophrenia. No detailed explanation has been offered for the difference. This article offers evidence that Kraepelin's and Bleuler's concepts were derived from a population largely suffering from organic disorders including the Parkinsonian sequelae of encephalitis lethargica; it describes the conceptual confusion which followed the introduction of the concept of post-encephalitic Parkinsonism and discusses some implications for the modern concept of schizophrenia. It is suggested that the differences between earlier and later groups of schizophrenics may be accounted for by the decline in prevalence of post-encephalitic Parkinsonism and of the neurological and behavioral sequelae of other diseases, and by the parallel unsystematic development of the concept of schizophrenia.
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PMID:Is schizophrenia what it was? A re-analysis of Kraepelin's and Bleuler's population. 225 39

The effect of systemic administration of ritanserin (R 55667), a 5-hydroxytryptamine (5-HT2) receptor antagonist, on midbrain dopamine (DA) neurons was studied with single cell recording techniques in the chloral hydrate anesthetized male rat. Dopamine cells of the zona compacta, substantia nigra (ZC-SN) and the ventral tegmental area (VTA) were identified by established criteria. Ritanserin (0.5-2.0 mg/kg, IV) dose-dependently increased both the burst firing and firing rate of the midbrain DA neurons. These effects were prevented by endogenous 5-HT depletion through pretreatment with the 5-HT synthesis inhibitor para-chlorophenylalanine (PCPA, 300 mg/kg, IP, x3), which did not significantly alter the firing characteristics of the midbrain DA cells when given alone. These results suggest that 5-HT exerts an inhibitory control of midbrain DA cell activity mediated by 5-HT2 receptors. The stimulatory effect of ritanserin on midbrain DA systems might contribute to some of its clinical effects, such as improvement of mood, drive and motivation as well as its therapeutic actions in parkinsonism and type II schizophrenia.
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PMID:Ritanserin, a 5-HT2 receptor antagonist, activates midbrain dopamine neurons by blocking serotonergic inhibition. 252 59

A yin-yang hypothesis is presented linking noradrenergic activity, thromboxane, melatonin, left hemisphere functioning, and cyclic AMP on the one hand, and dopamine, beta-endorphin, calcium, right hemisphere functioning, and cyclic GMP on the other. It is further suggested that there is a yoking of NA, TXA2, serotonin and melatonin in the left hemisphere, and a similar yoking of DA, BE, calcium and cGMP in the right. Evidence is presented to support the hypothesis that each element (NA, TXA2, etc.) on one side can modulate or balance a corresponding element (DA, BE, etc.) on the other. It is suggested that thromboxane is the key element in noradrenergic overactivity and that not taking this into consideration has confounded much prior research. This theory takes into account information processing models as well as pharmacological data and neurochemical theory on coupling of adenylate cyclase to its hormone receptors. Inhibiting noradrenergic overactivity can be obtained by inhibiting thromboxane and concomitantly activating opiate receptors. This protocol may have clinical utility in treating a wide range of disorders such as: anxiety, depression, schizophrenia, sleeplessness, withdrawal states, enuresis, Gilles de la Tourette syndrome, Parkinsonism, Alzheimers, dementia, anorexia, infant ruminations, essential tremor, spasticity of spinal cord injury, diarrhoea, ulcerative colitis, extrapyramidal symptoms, akathisia, neuroleptic malignant syndrome, attention deficit disorder, hyperhidrosis, and possibly AIDS.
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PMID:Inhibiting noradrenergic overactivity by inhibition of thromboxane and concomitant activation of opiate receptors via dietary means. 254 22

The results of two epidemiological studies suggest a hereditary predisposition to develop drug-induced parkinsonism. We investigated human leukocyte antigen (HLA) antigen prevalence rates in patients with neuroleptic-induced parkinsonism. Fifty-two male, white, neuroleptic-treated, chronic in-patients with DSM-III-diagnosed schizophrenia were examined for the presence of parkinsonism. Subjects were tested for 23 type A, 43 type B, 4 type C, and 10 type DR HLA antigens. The group of schizophrenic patients with parkinsonism (n = 29) was compared with the group of schizophrenic patients without parkinsonism (n = 23). There were no significant differences between the two groups with respect to age, duration of neuroleptic exposure, or anticholinergic drug exposure. One HLA antigen, B44, was significantly more prevalent in the group with parkinsonism than in the group without parkinsonism. We derived a relative risk of 7.16 for drug-induced parkinsonism with HLA-B44 present in this group of schizophrenic patients. These data indicate that HLA-B44 may play a role in genetic or immunologic susceptibility to develop drug-induced parkinsonism in white schizophrenic individuals.
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PMID:HLA antigens in drug-induced parkinsonism. 256 91

Tolerability of long term clozapine treatment (7-8 years) was investigated in 27 female patients (age 34-77 years). Diagnosis according to ICD 9 was schizophrenia in 21 patients, severe psychomotor agitation with mental deficiency in 4 patients and an "endogenous" depression in 2 patients. All patients had previously been treated with different neuroleptics but with inadequate response or distressing side effects. The duration of the disorder was 10-36 years, duration of hospitalisation 10-36 years. At the day of investigation the total dose of clozapine ranged from 52-826 g, the average total dose being 385 g. The daily dose of clozapine ranged from 75 to 600 mg, the average daily dose being 225 mg. Only 2 patients were treated exclusively with clozapine, the other 25 patients were also receiving other neuroleptics. Seventy eight per cent of the investigated patients complained about hypersalivation and 63% showed overweight. In 37% of the patients the EEG demonstrated abnormalities. Mild parkinsonism was reported in 15% and akathisia in 11% of the patients, all these patients being on combined treatment. Clozapine did not induce tardive dysakinesia (TD) in any of the patients within a treatment period of 7-8 years. It is concluded that a potential benefit of clozapine includes a low incidence of neurological side effects even after long term administration.
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PMID:Tolerability of long term clozapine treatment. 281 63

Movement abnormalities in neuroleptic-treated, psychiatric patients are classified as (a) initial syndromes, including dystonia, parkinsonism, and hyperkinetic abnormalities such as initial dyskinesia (ID) and akathisia, all of which are related to the neuroleptic dose and can be considered as overdose phenomena; (b) tardive syndromes, mainly the classic tardive dyskinesia (TD) syndrome, more seldom tardive akathisia and tardive dystonia, which may all develop or aggravate after withdrawal of neuroleptic treatment; and (c) age-related, spontaneous dyskinesia, akathisia, and dystonia, and schizophrenia-related, hyperkinetic, often stereotyped, movements and restlessness. ID and TD can occur simultaneously, and may depend, at least partially, on identical mechanisms. The pathophysiology of TD is still not clear, and the traditional dopamine (DA) hypersensitivity model seems inadequate. Animal experiments suggest that blockade of some DA receptors in the brain (e.g., in ventromedian striatum) may counteract hyperkinesia and produce parkinsonism, while a concomitant blockade of other similar receptors in other brain regions (e.g., in anterodorsal striatum) may aggravate movements. This offers an explanation for the concomitant occurrence of parkinsonism and hyperkinetic movement abnormalities (ID and akathisia) relatively early in a neuroleptic treatment, and may also contribute to the understanding of the pathophysiology of TD. It is concluded that pathophysiologically TD is a heterogeneous syndrome depending on a subtle balance between several neurotransmitters in the brain, including DA receptor blockade and hypersensitivity of DA and GABA receptors.
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PMID:Pathophysiological mechanisms underlying tardive dyskinesia. 286 Jun 66

Of 99 consecutive male patients studied at the North Chicago VA Tardive Dyskinesia Program, 58 had tardive dyskinesia and 41 did not. Factors that were significantly related, singly and in combinations, to tardive dyskinesia were 1) diagnosis of affective disorder with alcoholism and/or drug-induced parkinsonism, and 2) diagnosis of schizophrenia with advanced age (over 50) and/or prolonged hospitalization (over 14 years). A diagnosis of schizophrenia in patients under age 50 with short hospitalizations was not significantly associated with the presence of tardive dyskinesia.
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PMID:Vulnerability to tardive dyskinesia. 286 57

Zotepine, a new neuroleptic, was administered to 23 hospitalized patients with schizophrenia at doses of 75 to 600 mg/d for 21 to 42 days. Based upon analysis of conventional rating scales we observed a significant improvement (P less than 0.001) during week 1, which compound throughout the study period. After 21 days we identified 17 responders and 6 nonresponders, 2 of whom dropped out of the study because of a tonic-clonic seizure in one case and withdrawal of consent to further participation in the second case. During further treatment the improvement remaind stable in the responder group, while 1 nonresponder improved after 3 weeks of treatment. In 9 patients extrapyramidal symptoms were observed (6 parkinsonism, 2 early dyskinesia, 1 parkinsonism and early dyskinesia), which required sporadic (n = 3) or continuous (n = 2) treatment with biperiden in 5 cases. This low incidence of extrapyramidal symptoms necessitating coadministration of anticholinergic drugs suggests that the risk of inducing parkinsonism and dyskinesias during zotepine treatment is low. Comparison of cortisol, growth hormone and prolactin release in normal controls challenged with 25 mg zotepine showed that only prolactin secretion is increased, while secretion of cortisol and growth hormone remains unaffected. The clinical effects observed in the present study show that zotepine has potential value in the treatment of schizophrenia. The findings warrant further study in controlled trials.
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PMID:Clinical and neuroendocrine effects of zotepine--a new neuroleptic drug. 288 78

The benzodiazepine clonazepam was approved for the treatment of epilepsy in 1976. To study its use in acute mania, the author compared clonazepam with lithium in a crossover trial. Clonazepam proved more effective than lithium in controlling the symptoms of mania and caused fewer manifestations of parkinsonism. Associated side effects included ataxia, drowsiness, and behavioral changes. No treatment-emergent depression was observed. Neither clonazepam nor any other benzodiazepine is recommended in schizoaffective or schizophrenic disorders because of the high risk of dependence in those patients, in contrast to manic-depressives. For the maintenance treatment of bipolar disorder, lithium is recommended as the initial agent, with L-tryptophan added if concomitant medication is needed. Clonazepam can then be added as the anticonvulsant, if necessary. In the treatment of acute mania, clonazepam is recommended for the first week of treatment, and lithium is added in the beginning of the second week, thus avoiding the use of neuroleptics.
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PMID:The use of benzodiazepines in the treatment of manic-depressive illness. 290 43

Tardive dyskinesia (TD); abnormal involuntary movements appearing late in neuroleptic treatment) was described shortly after introduction of chlorpromazine and other antipsychotic agents in the 1950s. Consideration of this disorder as a common, progressive, and relentless problem of major public-health and medicolegal concern in the 1970s now appears to have been somewhat exaggerated. Several symptom patterns associated with neuroleptic treatment may or may not appropriately be lumped with the concept of TD (acute and withdrawal-emergent dyskinesias, dystonias, and akathisia, in particular); parkinsonism (with bradykinesia, rigidity, and tremor, including perioral tremor of the "rabbit syndrome") should be differentiated from TD, even though elements of both may occur together. Dyskinesias, more or less similar to TD, can occur in chronically ill neuropsychiatric patients not exposed to neuroleptics. Some may represent stereotyped behaviors of schizophrenia or undiagnosed neurological disorders, but a risk of spontaneous dyskinesias indistinguishable from TD averages about 5% (probably less in young patients). Mean prevalence rates for TD, corrected for spontaneous dyskinesias, average about 15-20% with higher risks at advancing ages. Incidence rates are less certain, but estimates average about 5% a year for at least several years in young patients, with higher rates within the first two years of treatment of elderly patients. Risk factors most clearly defined are advancing age, use of neuroleptic agents at relatively high daily doses for more than six months, and perhaps the diagnosis of a major affective disorder. Female gender and relatively high plasma levels of neuroleptic agents are less significant risk factors and other metabolic or neuroradiological indicators of risk remain unproved. The etiology of TD remains obscure.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A summary of current knowledge of tardive dyskinesia. 290 54


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