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)

Clozapine is the most effective antipsychotic medication currently in use, but there has been a paucity of well-controlled research on its efficacy with people with developmental disabilities. We present a set of guidelines to ensure proper utilization of clozapine in individuals with developmental disabilities, because it can offer them therapeutic advantages similar to those observed in people with schizophrenia. We provide recommendations regarding the use of clozapine that are based on three main sources: literature and published professional practice guidelines regarding the use of clozapine in individuals who do not have developmental disabilities, the limited literature on the use of clozapine in individuals who have developmental disabilities, and our own clinical experience. The first part of the guidelines contains an overview of necessary practical knowledge regarding side effects, dose and blood level considerations, and interactions with other medications, diet and tobacco smoking. In the second part, we offer procedures for selecting individuals for clozapine therapy based on proper indications and contraindications for treatment. We also include requirements regarding informed consent, dosage and special laboratory and clinical monitoring.
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PMID:Guidelines for the use of clozapine in individuals with developmental disabilities. 1604 Feb 29

Schizophrenia is a chronic and debilitating disease which is thought to arise from a neuro-developmental disorder. Both the stable tubule-only polypeptide (STOP) protein and the N-methyl-D-aspartate (NMDA) NR1 subunit are involved in neuronal development and physiology. It has therefore been postulated that transgenic mice lacking either the STOP or the NMDAR1 gene would show a 'schizophrenic-like' phenotype. Here, STOP knockout and NMDA NR1 hypomorphic mice were assessed in a behavioural measure that can be used to detect schizophrenic-like phenotypes: a change in sensorimotor gating, measured through prepulse inhibition (PPI). STOP knockout mice were further assessed in another measure of 'schizophrenic-like behaviour': hyperlocomotion. The PPI deficit exhibited by both the STOP knockout and NMDA knockdown mice could not be reversed by acute treatment with the atyptical antipsychotic, clozapine (1 mg/kg, i.p.) but the hyperlocomotion shown by the STOP knockout mice was reversed with the same acute dose of clozapine.
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PMID:STOP knockout and NMDA NR1 hypomorphic mice exhibit deficits in sensorimotor gating. 1604 5

This paper reviews the concept and recent studies on childhood and adolescent psychoses with special reference to schizophrenia. After a short historical introduction, the definition, classification, and epidemiology of child- and adolescent-onset psychoses are described, pointing out that some early-onset psychotic states seem to be related to schizophrenia (such as infantile catatonia) and others not (such as desintegrative disorder). The frequency of childhood schizophrenia is less than 1 in 10,000 children, but there is a remarkable increase in frequency between 13 and 18 years of age. Currently, schizophrenia is diagnosed according to ICD-10 and DSM-IV criteria. The differential diagnosis includes autism, desintegrative disorder, multiplex complex developmental disorder (MCDD) respectively multiple developmental impairment (MDI), affective psychoses, Asperger syndrome, drug-induced psychosis and psychotic states caused by organic disorders. With regard to etiology, there is strong evidence for the importance of genetic factors and for neurointegrative deficits preceding the onset of the disorder. Treatment is based upon a multimodal approach including antipsychotic medication (mainly by atypical neuroleptics), psychotherapeutic measures, family-oriented measures, and specific measures of rehabilitation applied in about 30% of the patients after completion of inpatient treatment. The long-term course of childhood- and adolescent-onset schizophrenia is worse than in adulthood schizophrenia, and the patients with manifestation of the disorder below the age of 14 have a very poor prognosis.
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PMID:Schizophrenia and related disorders in children and adolescents. 1635 6

Velocardiofacial/DiGeorge syndrome (VCFS/DGS) is a developmental disorder caused by a 1.5 to 3-Mb hemizygous 22q11.2 deletion. VCFS/DGS patients display malformations in multiple systems, as well as an increased frequency of neuropsychiatric defects including schizophrenia. Haploinsufficiency of TBX1 appears to be responsible for these physical malformations in humans and mice, but the genes responsible for the neuropsychiatric defects are unknown. In this study, two mouse models of VCFS/DGS, a deletion mouse model (Lgdel/+) and a single gene model (Tbx1 +/-), as well as a third mouse mutant (Gscl -/-) for a gene within the Lgdel deletion, were tested in a large behavioral battery designed to assess gross physical features, sensorimotor reflexes, motor activity nociception, acoustic startle, sensorimotor gating, and learning and memory. Lgdel/+ mice contain a 1.5-Mb hemizygous deletion of 27 genes in the orthologous region on MMU 16 and present with impairment in sensorimotor gating, grip strength, and nociception. Tbx1 +/- mice were impaired in grip strength similar to Lgdel/+ mice and movement initiation. Gscl -/- mice were not impaired in any of the administered tests, suggesting that redundant function of other Gsc family members may compensate for the loss of Gscl. Thus, although deletion of the genes in the Lgdel region in mice may recapitulate some of the behavioral phenotypes seen in humans with VCFS/DGS, these phenotypes are not found in mice with complete loss of Gscl or in mice with heterozygous loss of Tbx1, suggesting that the neuropsychiatric and physical malformations of VCFS/DGS may act by different genetic mechanisms.
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PMID:Behavior of mice with mutations in the conserved region deleted in velocardiofacial/DiGeorge syndrome. 1690 Mar 88

Awareness of childhood-onset schizophrenia is rapidly increasing, with a more precise definition now available of the clinical picture and early signs, the outcome and the treatment strategies. Premorbid developmental impairments, including language, motor and social deficits, are more frequent and more pronounced in earlier- than in later-onset forms of schizophrenia. This 'pan-dysmaturation' is reported from the first months of life in more than half of the children who will develop childhood-onset schizophrenia, and it suggests a more severe and early disruption of brain development compared with the adolescent- and adult-onset disorder. The insidious onset in at least 75% of children, the high rates of premorbid problems and the hesitancy on the part of clinicians to make a diagnosis of schizophrenia in a child usually delay the recognition of the syndrome. Elementary auditory hallucinations are the most frequent positive symptom, while visual and tactile hallucinations are rarer. Delusions are less complex than in adolescents and are usually related to childhood themes. Negative symptoms are largely predominant, namely flat or inappropriate affect. A marked deterioration from the previous level of functioning is present in all these children, and an impaired outcome is reported in approximately 50-60% of them. The main diagnostic challenges are with differentiating childhood-onset schizophrenia from affective disorders (both depression and bipolar disorder) with psychotic symptoms, pervasive developmental disorders and severe personality disorders. Post-traumatic stress disorder and obsessive-compulsive disorder without insight may also be misdiagnosed as schizophrenia. Furthermore, approximately 10% of children from the community report nonpsychotic hallucinations or delusions. Finally, children with atypical psychotic features that do not strictly fit diagnostic criteria for schizophrenia have been described, and new labels have been proposed to categorise these clinical patterns, such as multidimensionally impaired disorder and multiple complex developmental disorder. In the context of a multimodal approach, including behavioral, social, scholastic and familial interventions, a pharmacological treatment is usually the core treatment. Available experience from the few controlled studies, open studies and case reports on pharmacotherapy in children with schizophrenia aged <12 years is critically analysed in this review, with particular reference to the use of atypical antipsychotics in clinical practice. To date, the major evidence supports the efficacy of risperidone and olanzapine, while clozapine seems an effective option in treatment-refractory cases. Published experience with newer atypical antipsychotics (quetiapine, ziprasidone, aripiprazole) is still lacking in this age range. Safety data (namely extrapyramidal symptoms, weight gain, hyperprolactinaemia, haematological adverse effects, seizures, hepatotoxicity, metabolic effects, neuroleptic malignant syndrome and cardiovascular effects) are reviewed and discussed, along with strategies for management.
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PMID:Children with schizophrenia: clinical picture and pharmacological treatment. 1802 Apr 82

22q11.2 deletion syndrome (22q11.2DS) is a well-known genetic risk factor for schizophrenia. The catechol-O-methyltransferase (COMT) gene falls within the 22q11.2 minimal critical region of the deletion. Brain activity, as measured by functional magnetic resonance imaging (fMRI) during a Go/NoGo, response inhibition task was assessed in adolescents with 22q11.2DS (n = 13), typically developing (TD) controls (n = 14), and controls with developmental disability (DD, n = 9). Subjects with 22q11.2DS were also genotyped for the COMT Met/Val polymorphism. Groups did not differ on task performance. However, compared to both control groups, the 22q11.2DS group showed greater brain activation within left parietal regions. Comparison of brain activation between 22q11.2DS Met and Val subgroups revealed significantly increased activation (Met>Val) in the cingulate but not the dorsolateral prefrontal cortex. These preliminary findings suggest that adolescents with 22q11.2DS compensate for executive dysfunction via recruitment of parietal regions. Further, the COMT Met subgroup of 22q11.2DS may recruit additional cingulate activation for tasks requiring attention and inhibition. 22q11.2DS is a unique model for learning about the deleterious effects of decreased dosage of the COMT gene on brain function.
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PMID:Abnormal cortical activation during response inhibition in 22q11.2 deletion syndrome. 1742 9

We review the evidence on effectiveness of interventions for the treatment and prevention of selected mental disorders in low-income and middle-income countries. Depression can be treated effectively in such countries with low-cost antidepressants or with psychological interventions (such as cognitive-behaviour therapy and interpersonal therapies). Stepped-care and collaborative models provide a framework for integration of drug and psychological treatments and help to improve rates of adherence to treatment. First-generation antipsychotic drugs are effective and cost effective for the treatment of schizophrenia; their benefits can be enhanced by psychosocial treatments, such as community-based models of care. Brief interventions delivered by primary-care professionals are effective for management of hazardous alcohol use, and pharmacological and psychosocial interventions have some benefits for people with alcohol dependence. Policies designed to reduce consumption, such as increased taxes and other control strategies, can reduce the population burden of alcohol abuse. Evidence about the efficacy of interventions for developmental disabilities is inadequate, but community-based rehabilitation models provide a low-cost, integrative framework for care of children and adults with chronic mental disabilities. Evidence for mental health interventions for people who are exposed to conflict and other disasters is still weak-especially for interventions in the midst of emergencies. Some trials of interventions for prevention of depression and developmental delays in low-income and middle-income countries show beneficial effects. Interventions for depression, delivered in primary care, are as cost effective as antiretroviral drugs for HIV/AIDS. The process and effectiveness of scaling up mental health interventions has not been adequately assessed. Such research is needed to inform the continuing process of service reform and innovation. However, we recommend that policymakers should act on the available evidence to scale up effective and cost-effective treatments and preventive interventions for mental disorders.
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PMID:Treatment and prevention of mental disorders in low-income and middle-income countries. 1780 58

The Autism Diagnostic Observation Schedule (ADOS) and the Autism Diagnostic Interview - Revised (ADI-R) are considered to be the 'gold standard' in diagnostic evaluations for autism. Developed as research tools and now gaining wide clinical use, the ADOS/ADI-R assessment package has been demonstrated to differentiate children with autism from those with other developmental disabilities; however, little work concerning the reliability and validity of the tools in children with a known history of psychosis has been undertaken. We report on the administration of the ADOS, ADI-R and clinical judgment in three cases of Childhood-Onset Schizophrenia. All 3 children met both ADOS and ADI-R criteria for an autism spectrum diagnosis, even though none of them received a clinical diagnosis of autism from either a research child psychiatrist or an experienced clinically trained, research psychologist with expertise in autism. Issues concerning overlap of symptom presentation and implications for research and clinical use of these assessment tools are discussed.
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PMID:Use of the ADOS and ADI-R in children with psychosis: importance of clinical judgment. 1841 67

Neuregulin-1 (NRG-1) and its receptor ErbB4 are genetically associated with schizophrenia, a complex developmental disorder of high heritability but unknown etiology that has been proposed to result from deficits in functional connectivity and synaptic plasticity. Based on pharmacological evidence, imbalances in dopaminergic and glutamatergic transmission systems are believed to contribute to its pathophysiology, but genetic data supporting a causative role for either are sparse. Stimulation of NRG-1/ErbB4 signaling inhibits or reverts hippocampal long-term potentiation (LTP) at glutamatergic synapses between Schaeffer collateral afferents and CA1 pyramidal neurons (SC-->CA1). We have recently demonstrated that NRG-1 regulates glutamatergic plasticity by rapidly increasing extracellular hippocampal dopamine levels and activation of D4 dopamine receptors.7 These new findings position the NRG-1/ErbB4 signaling pathway at the crossroads between dopaminergic and glutamatergic neurotransmission and offer novel ways to consolidate genetic, functional and pharmacological data toward a better understanding of the etiological processes underlying schizophrenia, and the role of NRG-1 for normal synaptic function and plasticity. The currently available data suggest that hippocampal interneurons might play a crucial role in mediating NRG-1 induced depotentiation. This interpretation is in line with other evidence pointing towards an involvement of GABAergic cells in the etiology of schizophrenia.
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PMID:Neuregulin links dopaminergic and glutamatergic neurotransmission to control hippocampal synaptic plasticity. 1964 46

Schizophrenia is a severe mental illness that afflicts nearly 1% of the world's population. One of the cardinal pathological features of schizophrenia is perturbation in synaptic connectivity. Although the etiology of schizophrenia is unknown, it appears to be a developmental disorder involving the interaction of a potentially large number of risk genes, with no one gene producing a strong effect except rare, highly penetrant copy number variants. The purpose of this review is to detail how putative schizophrenia risk genes (DISC-1, neuregulin/ErbB4, dysbindin, Akt1, BDNF, and the NMDA receptor) are involved in regulating neuroplasticity and how alterations in their expression may contribute to the disconnectivity observed in schizophrenia. Moreover, this review highlights how many of these risk genes converge to regulate common neurotransmitter systems and signaling pathways. Future studies aimed at elucidating the functions of these risk genes will provide new insights into the pathophysiology of schizophrenia and will likely lead to the nomination of novel therapeutic targets for restoring proper synaptic connectivity in the brain in schizophrenia and related disorders.
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PMID:Neuroplasticity signaling pathways linked to the pathophysiology of schizophrenia. 2095 27


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