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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Perfil antipsicótico de alstonina : ação em modelos de sintomas negativos, alterações em aminas biogênicas e efeitos adversos em camundongos / Antipsychotic profile of alstonine : action in animal models of negative symptoms, alterations in biogenic amines and side effects in mice.

Linck, Viviane de Moura January 2008 (has links)
A esquizofrenia é um transtorno psiquiátrico grave, caracterizado por distúrbios do pensamento, prejuízo da lógica, alterações cognitivas e emocionais, e/ou isolamento social. Apesar da introdução de novos antipsicóticos, um grupo considerável de pacientes ainda é refratário aos tratamentos disponíveis. Além disso, a alta incidência de efeitos adversos leva à baixa adesão ao tratamento em esquizofrênicos. O desenvolvimento de tratamentos mais eficazes e com menor incidência de efeitos adversos, que aumentem a adesão ao tratamento e melhorem a qualidade de vida destes pacientes, é assim altamente desejável. Em uma expedição etnofarmacológica entre os Igbo na Nigéria identificou-se uma preparação a base de plantas usada no tratamento de pacientes com distúrbios mentais. O alcalóide indólico alstonina é o componente majoritário desta preparação, e possui um claro perfil comportamental de antipsicótico atípico em modelos animais de sintomas positivos, com aparentes vantagens em relação à clozapina. Este trabalho teve o objetivo principal de dar continuidade à caracterização de alstonina como fármaco antipsicótico. Demonstramos que este alcalóide aumenta a interação social e previne o déficit de interação social induzido por MK801 em camundongos, sugerindo utilidade da alstonina no manejo de sintomas negativos da esquizofrenia. Quanto ao mecanismo de ação, a avaliação do efeito de alstonina sobre as aminas biogênicas em córtex frontal e estriado de camundongos sugere que este alcalóide potencia a transmissão serotonérgica e aumenta o catabolismo intraneuronal de dopamina. Quanto aos possíveis efeitos adversos, dados preliminares mostram que alstonina não altera os níveis de prolactina, não induz ganho de peso corporal, mas impede a diminuição da glicemia induzida por jejum. Este trabalho confirma o perfil antipsicótico de alstonina bem como a possibilidade de um mecanismo de ação inovador. Os resultados justificam investimento em novos estudos, quer seja para o desenvolvimento de alstonina como fármaco, quer no sentido de trazer inovação farmacodinâmica tão necessária para avançar no tratamento da esquizofrenia. / Schizophrenia is a serious psychiatric illness, characterized by alterations in thought, deficits in logical thinking, changes in cognition and emotion, and/or social isolation. Despite the introduction of newer antipsychotic drugs, a sizable number of patients are still refractory to the available medication. Moreover, the high incidence of side effects determines the low adhesion of patients to treatments. The development of more efficacious treatments with lower incidence of side effects, ameliorating adhesion to treatment and improving patient’s quality of life is, therefore, sorely wanted. During an ethnopharmacological expedition among the Igbo in Nigeria, a plant based treatment to mentally ill patients was identified. The indole alkaloid alstonine is the major component of this remedy and shown to have a clear behavioral profile of an atypical antipsychotic in rodent models, apparently with advantages in comparison to clozapine. This study had the main purpose of continuing the characterization of alstonine as an antipsychotic drug. We show that this alkaloid increases social interaction and prevents MK801-induced social withdrawal in mice, pointing to its utility in managing negative symptoms of schizophrenia. Regarding its mechanism of action, the effects of alstonine on biogenic amines in mice frontal cortex and striatum suggest that it enhances serotonergic neurotransmission and increases the intra neuronal catabolism of dopamine. In relation to possible side effects, preliminary data suggest that alstonine does not affect prolactin levels, does not induce gains in body weight, but prevents the expected fasting-induced decrease in glucose levels. This study corroborates the antipsychotic profile of alstonine, as well as the possibility of an innovative mechanism of action. These results justify further studies either to develop alstonine as a medication, or to bring pharmacodynamic innovation so sorely needed to move forward in the treatment of schizophrenia.
12

Perfil antipsicótico de alstonina : ação em modelos de sintomas negativos, alterações em aminas biogênicas e efeitos adversos em camundongos / Antipsychotic profile of alstonine : action in animal models of negative symptoms, alterations in biogenic amines and side effects in mice.

Linck, Viviane de Moura January 2008 (has links)
A esquizofrenia é um transtorno psiquiátrico grave, caracterizado por distúrbios do pensamento, prejuízo da lógica, alterações cognitivas e emocionais, e/ou isolamento social. Apesar da introdução de novos antipsicóticos, um grupo considerável de pacientes ainda é refratário aos tratamentos disponíveis. Além disso, a alta incidência de efeitos adversos leva à baixa adesão ao tratamento em esquizofrênicos. O desenvolvimento de tratamentos mais eficazes e com menor incidência de efeitos adversos, que aumentem a adesão ao tratamento e melhorem a qualidade de vida destes pacientes, é assim altamente desejável. Em uma expedição etnofarmacológica entre os Igbo na Nigéria identificou-se uma preparação a base de plantas usada no tratamento de pacientes com distúrbios mentais. O alcalóide indólico alstonina é o componente majoritário desta preparação, e possui um claro perfil comportamental de antipsicótico atípico em modelos animais de sintomas positivos, com aparentes vantagens em relação à clozapina. Este trabalho teve o objetivo principal de dar continuidade à caracterização de alstonina como fármaco antipsicótico. Demonstramos que este alcalóide aumenta a interação social e previne o déficit de interação social induzido por MK801 em camundongos, sugerindo utilidade da alstonina no manejo de sintomas negativos da esquizofrenia. Quanto ao mecanismo de ação, a avaliação do efeito de alstonina sobre as aminas biogênicas em córtex frontal e estriado de camundongos sugere que este alcalóide potencia a transmissão serotonérgica e aumenta o catabolismo intraneuronal de dopamina. Quanto aos possíveis efeitos adversos, dados preliminares mostram que alstonina não altera os níveis de prolactina, não induz ganho de peso corporal, mas impede a diminuição da glicemia induzida por jejum. Este trabalho confirma o perfil antipsicótico de alstonina bem como a possibilidade de um mecanismo de ação inovador. Os resultados justificam investimento em novos estudos, quer seja para o desenvolvimento de alstonina como fármaco, quer no sentido de trazer inovação farmacodinâmica tão necessária para avançar no tratamento da esquizofrenia. / Schizophrenia is a serious psychiatric illness, characterized by alterations in thought, deficits in logical thinking, changes in cognition and emotion, and/or social isolation. Despite the introduction of newer antipsychotic drugs, a sizable number of patients are still refractory to the available medication. Moreover, the high incidence of side effects determines the low adhesion of patients to treatments. The development of more efficacious treatments with lower incidence of side effects, ameliorating adhesion to treatment and improving patient’s quality of life is, therefore, sorely wanted. During an ethnopharmacological expedition among the Igbo in Nigeria, a plant based treatment to mentally ill patients was identified. The indole alkaloid alstonine is the major component of this remedy and shown to have a clear behavioral profile of an atypical antipsychotic in rodent models, apparently with advantages in comparison to clozapine. This study had the main purpose of continuing the characterization of alstonine as an antipsychotic drug. We show that this alkaloid increases social interaction and prevents MK801-induced social withdrawal in mice, pointing to its utility in managing negative symptoms of schizophrenia. Regarding its mechanism of action, the effects of alstonine on biogenic amines in mice frontal cortex and striatum suggest that it enhances serotonergic neurotransmission and increases the intra neuronal catabolism of dopamine. In relation to possible side effects, preliminary data suggest that alstonine does not affect prolactin levels, does not induce gains in body weight, but prevents the expected fasting-induced decrease in glucose levels. This study corroborates the antipsychotic profile of alstonine, as well as the possibility of an innovative mechanism of action. These results justify further studies either to develop alstonine as a medication, or to bring pharmacodynamic innovation so sorely needed to move forward in the treatment of schizophrenia.
13

Perfil antipsicótico de alstonina : ação em modelos de sintomas negativos, alterações em aminas biogênicas e efeitos adversos em camundongos / Antipsychotic profile of alstonine : action in animal models of negative symptoms, alterations in biogenic amines and side effects in mice.

Linck, Viviane de Moura January 2008 (has links)
A esquizofrenia é um transtorno psiquiátrico grave, caracterizado por distúrbios do pensamento, prejuízo da lógica, alterações cognitivas e emocionais, e/ou isolamento social. Apesar da introdução de novos antipsicóticos, um grupo considerável de pacientes ainda é refratário aos tratamentos disponíveis. Além disso, a alta incidência de efeitos adversos leva à baixa adesão ao tratamento em esquizofrênicos. O desenvolvimento de tratamentos mais eficazes e com menor incidência de efeitos adversos, que aumentem a adesão ao tratamento e melhorem a qualidade de vida destes pacientes, é assim altamente desejável. Em uma expedição etnofarmacológica entre os Igbo na Nigéria identificou-se uma preparação a base de plantas usada no tratamento de pacientes com distúrbios mentais. O alcalóide indólico alstonina é o componente majoritário desta preparação, e possui um claro perfil comportamental de antipsicótico atípico em modelos animais de sintomas positivos, com aparentes vantagens em relação à clozapina. Este trabalho teve o objetivo principal de dar continuidade à caracterização de alstonina como fármaco antipsicótico. Demonstramos que este alcalóide aumenta a interação social e previne o déficit de interação social induzido por MK801 em camundongos, sugerindo utilidade da alstonina no manejo de sintomas negativos da esquizofrenia. Quanto ao mecanismo de ação, a avaliação do efeito de alstonina sobre as aminas biogênicas em córtex frontal e estriado de camundongos sugere que este alcalóide potencia a transmissão serotonérgica e aumenta o catabolismo intraneuronal de dopamina. Quanto aos possíveis efeitos adversos, dados preliminares mostram que alstonina não altera os níveis de prolactina, não induz ganho de peso corporal, mas impede a diminuição da glicemia induzida por jejum. Este trabalho confirma o perfil antipsicótico de alstonina bem como a possibilidade de um mecanismo de ação inovador. Os resultados justificam investimento em novos estudos, quer seja para o desenvolvimento de alstonina como fármaco, quer no sentido de trazer inovação farmacodinâmica tão necessária para avançar no tratamento da esquizofrenia. / Schizophrenia is a serious psychiatric illness, characterized by alterations in thought, deficits in logical thinking, changes in cognition and emotion, and/or social isolation. Despite the introduction of newer antipsychotic drugs, a sizable number of patients are still refractory to the available medication. Moreover, the high incidence of side effects determines the low adhesion of patients to treatments. The development of more efficacious treatments with lower incidence of side effects, ameliorating adhesion to treatment and improving patient’s quality of life is, therefore, sorely wanted. During an ethnopharmacological expedition among the Igbo in Nigeria, a plant based treatment to mentally ill patients was identified. The indole alkaloid alstonine is the major component of this remedy and shown to have a clear behavioral profile of an atypical antipsychotic in rodent models, apparently with advantages in comparison to clozapine. This study had the main purpose of continuing the characterization of alstonine as an antipsychotic drug. We show that this alkaloid increases social interaction and prevents MK801-induced social withdrawal in mice, pointing to its utility in managing negative symptoms of schizophrenia. Regarding its mechanism of action, the effects of alstonine on biogenic amines in mice frontal cortex and striatum suggest that it enhances serotonergic neurotransmission and increases the intra neuronal catabolism of dopamine. In relation to possible side effects, preliminary data suggest that alstonine does not affect prolactin levels, does not induce gains in body weight, but prevents the expected fasting-induced decrease in glucose levels. This study corroborates the antipsychotic profile of alstonine, as well as the possibility of an innovative mechanism of action. These results justify further studies either to develop alstonine as a medication, or to bring pharmacodynamic innovation so sorely needed to move forward in the treatment of schizophrenia.
14

Vilka faktorer påverkar livskvalitet hos individer med schizofreni - ett omvårdnadsperspektiv : En litteraturstudie

Lazcano Barra, Yasna, Ullmark, Sebastian January 2017 (has links)
Bakgrund: Det finns idag cirka 35 000 personer som lider av schizofreni i Sverige. De schizofrena symtomen påverkar patientens livskvalitet i olika utsträckning. Negativa symtom som undergrupp har till skillnad från övriga symtom visat sig ha en sämre respons på medicinering och bidrar därmed till en risk för sämre livskvalitet. På grund av fortsatta utmaningar att behandla negativa symtom krävs ytterligare forskning på området för att optimera omvårdnaden för dessa patienter och på så sätt förbättra en riskerad livskvalitet. Syfte: Syftet var att undersöka hur individer med negativa symtom inom ramen för schizofreni upplevde sin livskvalitet och omvårdnaden kring sin sjukdom. Metod: En litteraturstudie har utförts, där artiklar relevanta för att besvara syftet och frågeställningar har granskats. Artiklarna i denna litteraturstudie granskades strukturerat och analyserades med en innehållsanalys. Resultat: Faktorer som påverkar livskvalitet hos schizofrena patienter delades in i kategorierna; generella negativa symtom, kognitiva svårigheter och sociala faktorer, som delades upp i underkategorierna; stigmatisering, socialt nätverk, sociodemografiska förhållanden och arbetsförhållanden. De omvårdnadseffekter som påverkade livskvalitet visade sig vara; vårdkontext, stöd och utbildning från vården samt coping-strategier. Slutsats: Schizofrena individer påverkas i stor utsträckning av hur vården och samhället ser på dem. Sammanvägt upplever patientgruppen att en ökad livskvalitet var sammankopplad med socialt stöd och en vårdkontext som fokuserade på att förena ett fungerande privatliv med behandling. / Background: In Sweden, 35 000 individuals are affected by schizophrenia. The various symptoms of the disease have a major impact on the individuals’ quality of life. However, individuals with negative symptoms, have been shown to respond poorly to traditional pharmacological treatment. Because of this, patients who suffer from severe negative symptoms are at risk of poorer quality of life. Due to continued challenges to treat negative symptoms, further research is required to provide an optimized care for this vulnerable group. Aim: The aim was to study how schizophrenic individuals with characteristically negative symptoms experience quality of life as well as their experiences of the care provided to them. Method: A literature study has been conducted where articles relevant to answer the purpose and questions have been examined. The included articles were systematically analyzed through content analysis. Results: Quality of life in schizophrenic patients was affected by negative symptoms, cognitive difficulties and social factors, the latter divided in the sub-categories; stigmatization, social networking, sociodemographic conditions and working conditions. The caregiving factors that had an impact on quality of life were proven to be: the context in which the care was given, support and education from healthcare and coping strategies. Conclusion: Schizophrenic individuals are greatly affected by how caregivers and the society view them. Patients experienced that an improvement in quality of life is linked to social support and a context of caregiving that focused on combine the treatment with a functioning private life.
15

Social Anhedonia in the Daily Lives of People with Schizophrenia: Examination of Anticipated and Consummatory Pleasure

Danielle Abel (16024717) 30 August 2023 (has links)
<p>  </p> <p>Social withdrawal is a disabling feature of schizophrenia. To understand its development, researchers have focused on social anhedonia— diminished pleasure from social interactions. Discrepancies in anticipated versus consummatory pleasure for non-social stimuli are well-documented in schizophrenia. Thus, a similar emotional paradox may underlie social anhedonia. If so, our understanding of social anhedonia—including how to treat it in schizophrenia—could be enhanced. This project used a 5-day experience sampling method (ESM) to measure discrepancies between anticipated and consummatory pleasure for real-world social activities in people with schizophrenia and healthy controls (<em>n=</em>30/group). Results suggest people with schizophrenia exhibited similar levels of anticipated and consummatory social pleasure as controls, and both groups were accurate in their short-term predictions of pleasure. Yet, healthy control participants were somewhat more precise in their short-term pleasure predictions, and clinical interviews revealed those with schizophrenia showed moderate deficits in long-term social pleasure prediction. Negative symptoms and cognitive impairment in schizophrenia were related to anticipated, but not consummatory, social pleasure, suggesting anhedonia is driven by deficits in thinking about pleasure, rather than inability to experience pleasure. Clinical implications include focusing on building upon short-term ability to predict pleasure in therapy in order to increase social motivation in schizophrenia. Moreover, exploratory analyses revealed differences in qualitative aspects of social activities such as level of engagement may lead to social anhedonia in schizophrenia and are a promising treatment target for addressing social dysfunction.</p>
16

Excitabilidade cortical motora como preditora de resposta na esquizofrenia / Motor cortical excitability as a response prediction in schizophrenia

Gordon, Pedro Caldana 08 November 2018 (has links)
O desenvolvimento da estimulação magnética transcraniana (EMT) permitiu o estudo de potenciais evocados motores eliciados pela estimulação direta do córtex cerebral de forma não-invasiva. Foi observado que diferentes paradigmas de estimulação cortical por EMT apresentam diferentes padrões de resposta, que posteriormente foram associados ao funcionamento de circuitos corticais GABAérgicos e glutamatérgicos do córtex motor, compondo assim índices de excitabilidade cortical motora (ECM). Ademais, desvios da normalidade de tais índices foram encontrados em diversas condições clínicas, incluindo transtornos mentais como a esquizofrenia. O uso dessas medidas também auxiliou o desenvolvimento da estimulação transcraniana por corrente contínua (ETCC), técnica que se mostrou capaz de produzir efeitos neuromodulatórios no sistema nervoso central de forma segura e com mínimos efeitos adversos. Tal técnica vem apresentando possibilidades terapêuticas promissoras, como por exemplo, tendo sido observado sua eficácia no alívio de alucinações auditivas de indivíduos com esquizofrenia. O uso de ETCC para tratamento de sintomas negativos da esquizofrenia também pode vir a se mostrar uma abordagem eficaz, e a análise da ECM pode auxiliar no entendimento dos seus mecanismos de ação e atuar como possível preditor de resposta terapêutica. O objetivo do presente estudo é avaliar o perfil de ECM em um grupo de indivíduos com esquizofrenia, e as possíveis influências de um protocolo terapêutico utilizando ETCC sobre essas medidas. Com esse objetivo, foi selecionada uma coorte de sujeitos com esquizofrenia que participou em ensaio clínico randomizado e controlado com placebo (estimulação sham), tendo a ETCC como intervenção ativa alvo. A ECM foi mensurada na avaliação inicial dos sujeitos, assim como após a primeira sessão de ETCC, e quando da avaliação de desfecho primário. O protocolo terapêutico de ETCC envolveu a colocação de 2 eletrodos de área 5x7 cm, pólo anódico aplicado sobre região correspondente ao córtex pré-frontal dorsolateral esquerdo e pólo catódico aplicado sobre córtex de transição temporoparietal esquerdo; com intensidade de corrente de 2 mA, aplicada por 20 minutos. Cada sujeito foi submetido a 10 sessões no total. Encontramos que idade se correlacionou com diminuição da inibição intracortical, reproduzindo resultado previamente encontrado em indivíduos saudáveis. Acerca da modulação da ECM após sessão de ETCC, observamos que sujeitos submetidos à intervenção ativa apresentaram aumento da inibição intracortical no hemisfério estimulado, em oposição à ausência de mudança significativa da ECM nos sujeitos que receberam estimulação placebo. Os resultados sugerem que sessão de ETCC, utilizando os parâmetros aplicados neste estudo, levou ao aumento da inibição intracortical. Devido a evidências prévias de déficit de inibição intracortical em pessoas com esquizofrenia, é possível que o fenômeno observado represente mecanismo terapêutico da ETCC. É necessário verificar se tal efeito sobre a ECM acompanha medidas objetivas de resposta clinica. Caso isto se comprove, a ECM pode se tornar um valioso marcador de resposta terapêutica e evolução clinica em pacientes com esquizofrenia / The development of transcranial magnetic stimulation allowed the study of motor evoked potentials by applying direct stimuli to the brain cortex in a non-invasive fashion. Different stimulation protocols were observed to yield different response patterns, which were later associated with the functioning of cortical GABAergic and glutamatergic circuits, assembled as motor cortex excitability indices. Also, deviations from normality of such indices were observed in several clinical conditions, including mental disorders such as schizophrenia. The use of these measurements also helped the development of transcranial direct current stimulation (tDCS), a technique which was shown to promote neuromodulatory effects in central nervous system, with potential treatment applications. This technique has been used with success in the treatment of auditory hallucinations in patients with schizophrenia. The use of tDCS might also be effective in the treatment of negative symptoms of schizophrenia, and motor cortex excitability analysis might be used to clarify its physiological effects and act as a possible treatment response predictor. The aim of the present study is to evaluate the motor cortical excitability profile of individuals with schizophrenia, as well as possible influences of tDCS over these measurements. With this aim, we selected a cohort of subjects with schizophrenia who participated in a randomized placebo controlled clinical trial using transcranial direct current stimulation (and sham stimulation for placebo), and measuring motor cortical excitability during baseline evaluation, after the first stimulation session, and at the time of the primary outcome evaluation. The transcranial direct current stimulation protocol used in the present study involved the use of 2 electrodes of area 5x7 cm, anode placed over the region corresponding to the left dorsolateral prefrontal cortex, and cathode over the left cortical temporoparietal juntion. A current of 2 mA intensity was applied for 20 minutes. Each subject underwent a total of 10 sessions. We found that age was correlated to reduced intracortical inhibition, as has been previously found in healthy subjects. Regarding changes of motor cortical excitability following a transcranial direct current stimulation session, we observed that subjects that received the active stimulation displayed an increase in intracortical inhibition, as opposed to those who received sham stimulation, which did not present with any significant change. Results suggest that transcranial direct current stimulation session, using the parameters described in this study, led to an increase in intracortical inhibition. Given previous evidence of intracortical inhibition deficit in individuals with schizophrenia, it is possible that the observed phenomenon corresponds to a treatment mechanism of the electrical stimulation in this population. This need to be confirmed by comparing such changes in cortical excitability to objective measurements of clinical improvement. In case that is confirmed, measurement of motor cortical excitability may have a valuable application as a marker of treatment response and clinical outcome for patients with schizophrenia
17

Excitabilidade cortical motora como preditora de resposta na esquizofrenia / Motor cortical excitability as a response prediction in schizophrenia

Pedro Caldana Gordon 08 November 2018 (has links)
O desenvolvimento da estimulação magnética transcraniana (EMT) permitiu o estudo de potenciais evocados motores eliciados pela estimulação direta do córtex cerebral de forma não-invasiva. Foi observado que diferentes paradigmas de estimulação cortical por EMT apresentam diferentes padrões de resposta, que posteriormente foram associados ao funcionamento de circuitos corticais GABAérgicos e glutamatérgicos do córtex motor, compondo assim índices de excitabilidade cortical motora (ECM). Ademais, desvios da normalidade de tais índices foram encontrados em diversas condições clínicas, incluindo transtornos mentais como a esquizofrenia. O uso dessas medidas também auxiliou o desenvolvimento da estimulação transcraniana por corrente contínua (ETCC), técnica que se mostrou capaz de produzir efeitos neuromodulatórios no sistema nervoso central de forma segura e com mínimos efeitos adversos. Tal técnica vem apresentando possibilidades terapêuticas promissoras, como por exemplo, tendo sido observado sua eficácia no alívio de alucinações auditivas de indivíduos com esquizofrenia. O uso de ETCC para tratamento de sintomas negativos da esquizofrenia também pode vir a se mostrar uma abordagem eficaz, e a análise da ECM pode auxiliar no entendimento dos seus mecanismos de ação e atuar como possível preditor de resposta terapêutica. O objetivo do presente estudo é avaliar o perfil de ECM em um grupo de indivíduos com esquizofrenia, e as possíveis influências de um protocolo terapêutico utilizando ETCC sobre essas medidas. Com esse objetivo, foi selecionada uma coorte de sujeitos com esquizofrenia que participou em ensaio clínico randomizado e controlado com placebo (estimulação sham), tendo a ETCC como intervenção ativa alvo. A ECM foi mensurada na avaliação inicial dos sujeitos, assim como após a primeira sessão de ETCC, e quando da avaliação de desfecho primário. O protocolo terapêutico de ETCC envolveu a colocação de 2 eletrodos de área 5x7 cm, pólo anódico aplicado sobre região correspondente ao córtex pré-frontal dorsolateral esquerdo e pólo catódico aplicado sobre córtex de transição temporoparietal esquerdo; com intensidade de corrente de 2 mA, aplicada por 20 minutos. Cada sujeito foi submetido a 10 sessões no total. Encontramos que idade se correlacionou com diminuição da inibição intracortical, reproduzindo resultado previamente encontrado em indivíduos saudáveis. Acerca da modulação da ECM após sessão de ETCC, observamos que sujeitos submetidos à intervenção ativa apresentaram aumento da inibição intracortical no hemisfério estimulado, em oposição à ausência de mudança significativa da ECM nos sujeitos que receberam estimulação placebo. Os resultados sugerem que sessão de ETCC, utilizando os parâmetros aplicados neste estudo, levou ao aumento da inibição intracortical. Devido a evidências prévias de déficit de inibição intracortical em pessoas com esquizofrenia, é possível que o fenômeno observado represente mecanismo terapêutico da ETCC. É necessário verificar se tal efeito sobre a ECM acompanha medidas objetivas de resposta clinica. Caso isto se comprove, a ECM pode se tornar um valioso marcador de resposta terapêutica e evolução clinica em pacientes com esquizofrenia / The development of transcranial magnetic stimulation allowed the study of motor evoked potentials by applying direct stimuli to the brain cortex in a non-invasive fashion. Different stimulation protocols were observed to yield different response patterns, which were later associated with the functioning of cortical GABAergic and glutamatergic circuits, assembled as motor cortex excitability indices. Also, deviations from normality of such indices were observed in several clinical conditions, including mental disorders such as schizophrenia. The use of these measurements also helped the development of transcranial direct current stimulation (tDCS), a technique which was shown to promote neuromodulatory effects in central nervous system, with potential treatment applications. This technique has been used with success in the treatment of auditory hallucinations in patients with schizophrenia. The use of tDCS might also be effective in the treatment of negative symptoms of schizophrenia, and motor cortex excitability analysis might be used to clarify its physiological effects and act as a possible treatment response predictor. The aim of the present study is to evaluate the motor cortical excitability profile of individuals with schizophrenia, as well as possible influences of tDCS over these measurements. With this aim, we selected a cohort of subjects with schizophrenia who participated in a randomized placebo controlled clinical trial using transcranial direct current stimulation (and sham stimulation for placebo), and measuring motor cortical excitability during baseline evaluation, after the first stimulation session, and at the time of the primary outcome evaluation. The transcranial direct current stimulation protocol used in the present study involved the use of 2 electrodes of area 5x7 cm, anode placed over the region corresponding to the left dorsolateral prefrontal cortex, and cathode over the left cortical temporoparietal juntion. A current of 2 mA intensity was applied for 20 minutes. Each subject underwent a total of 10 sessions. We found that age was correlated to reduced intracortical inhibition, as has been previously found in healthy subjects. Regarding changes of motor cortical excitability following a transcranial direct current stimulation session, we observed that subjects that received the active stimulation displayed an increase in intracortical inhibition, as opposed to those who received sham stimulation, which did not present with any significant change. Results suggest that transcranial direct current stimulation session, using the parameters described in this study, led to an increase in intracortical inhibition. Given previous evidence of intracortical inhibition deficit in individuals with schizophrenia, it is possible that the observed phenomenon corresponds to a treatment mechanism of the electrical stimulation in this population. This need to be confirmed by comparing such changes in cortical excitability to objective measurements of clinical improvement. In case that is confirmed, measurement of motor cortical excitability may have a valuable application as a marker of treatment response and clinical outcome for patients with schizophrenia
18

Polimorfismo Val158Met del gen catecol-o-metiltransferasa y características clínicas en primeros episodios de psicosis

Pelayo Terán, José María 28 February 2011 (has links)
La esquizofrenia está considerada un síndrome clínico heterogéneo con una etiopatogenia de origen multifactorial, en el que se incluyen factores ambientales, caracteriales y genéticos. A pesar de que más del 50% de la variabilidad de la enfermedad se puede deber a uno o varios factores genéticos, sólo un número limitado de variantes de riesgo genético y con un efecto muy débil han podido ser identificados. Muchos de ellos no han podido reproducirse tanto por la diversidad de las muestras y poblaciones estudiadas como por su asociación a diversas enfermedades mentales. Parte de esta heterogeneidad ha intentado ser solventada mediante el uso de endofenotipos o fenotipos intermedios y marcadores biológicos, usados como marcadores de vulnerabilidad genética. El gen de la Catecol-O-Metil Transferasa (COMT), que codifica un enzima catabolizador de dopamina en el córtex prefrontal ha sido estudiado como uno de los genes candidatos más prometedores en el estudio de la etiopatogenia de la esquizofrenia, especialmente el polimorfismo rs4680 (COMT Val158Met). La posibilidad de asociar alteraciones en la regulación dopaminérgica prefrontal se encontraría refrendada por la hipótesis dopaminérgica revisada, según la cual, en la esquizofrenia existiría un desequilibrio dopaminérgico, con un incremento en la función dopaminérgica subcortical D2 y un déficit de estimulación D1 cortical. El polimorfismo COMT Val158Met no ha podido confirmar su asociación con esquizofrenia, existiendo en todo caso un riesgo muy débil asociado al alelo hiperfuncionante Val158. El estudio de endofenotipos y marcadores biológicos ha sugerido la asociación del polimorfismo con alteraciones cognitivas, neurofisiológicas, neuroanatómicas y a fenotipos clínicos como agresividad, suicidio, síntomas psicóticos, edad de inicio y respuesta clínica, encontrándose resultados heterogéneos, así como la existencia de una modulación del riesgo de asociación por el consumo de cannabis. Gran parte de la heterogeneidad puede explicarse por problemas metodológicos, relacionados con la validez y representatividad de las muestras, que podrían solventarse con la recogida sistemática de variables en muestras epidemiológicas en fases iniciales de la enfermedad. Partiendo de la hipótesis de la existencia de una alteración dopaminérgica prefrontal en la esquizofenia, el alelo Val158 del gen COMT estaría asociado a una expresión de síntomas psicóticos más graves, especialmente los negativos y a factores de mal pronóstico. Igualmente el consumo de cannabis podría modular este riesgo, incrementando el riesgo o contrarrestando los factores protectores. El objetivo principal fue estudiar la asociación de la presentación clínica y evolución a las seis semanas de tratamiento antipsicótico de pacientes con un primer episodio de psicosis y las variantes del polimorfismo COMT Val158Met así como su interacción con el consumo de cánnabis premórbido. Los objetivos secundarios fueron estudiar la incidencia de esquizofrenia y validar la representatividad de la muestra, analizar la relación entre el polimorfismo Val158Met y sintomatología clínica, edad de inicio, respuesta al tratamiento y estimar la presencia de interacciones gen-ambiente con el consumo de cánnabis premórbido. Para ello, se reclutaron 174 pacientes consecutivos con un primer episodio de psicosis de esquizofrenia, trastorno esquizofreniforme, trastorno esquizoafectivo, trastorno psicótico breve o trastorno psicótico no especificado, incluidos dentro del programa PAFIP, diseñado para la detección y tratamiento de los casos incidentes en la comunidad de Cantabria de Febrero 2001 a Febrero 2005. Los pacientes fueron evaluados con una entrevista semiestructurada, las escalas SANS, SAPS, HDRS, CDS, YMRS y la entrevista SCID-I. Fueron seguidos durante las primeras seis semanas de tratamiento antipsicótico de asignación aleatoria (olanzapina, risperidona o haloperidol). El genotipo del polimorfismo rs4680 se determinó en muestras de sangre venosa. Un primer estudio mostró una incidencia tratada de 1.38/10000 y la asociación de esta incidencia a factores de riesgo como edad menor de 25 años, sexo masculino, estado marital soltero, desempleo nivel educativo primario, ambiente urbano y consumo de cannabis. Un segundo estudio encontró una asociación del alelo Val158 con sintomatología negativa al inicio y edad de inicio temprana, diagnóstico de esquizofrenia y duración de psicosis sin tratar prolongada en mujeres. En un tercer estudio se mostró la asociación del consumo de cánnabis premórbido con edad de inicio más temprana y una interacción entre consumo de cannabis y el genotipo, de modo que el consumo de cannabis contrarresta el efecto protector del alelo 158 Met. Finalmente, en un cuarto estudio se confirmó la persistencia de la asociación del genotipo Val158Met con mayor sintomatología negativa tras seis semanas de tratamiento, no encontrando diferencias en cuanto a la respuesta clínica. Los resultados muestran que el polimorfismo COMT Val158Met pueden estar asociados a una edad de inicio más temprana y una mayor gravedad de síntomas negativos. Del mismo modo, el consumo de cánnabis premórbido se asocia a una menor edad de inicio y se encuentra un patrón de interacción con el polimorfismo, eliminando los efectos protectores del alelo Met158. Los hallazgos sugieren la importancia del polimorfismo COMT Val158Met y del consumo de cannabis en la etiopatogenia de la esquizofrenia, que podría explicarse por la disminución de trasmisión dopaminérgica prefrontal. / The schizophrenia is considered a heterogeneous syndrome which has multifactorial causes, including environmental, characterial and genetic factors. Despite the fact that 50% of the variability of the illness is explained by genetic factors, only a limited number of genetic variants have been identified as weak risk factors. Most of them have not been replicated because of the heterogeneity of the studied samples and the association with other mental illnesses. This variability has been tried to be solved by the use of endophenotypes and biological markers, as indicators of genetic vulnerability. Catechol-O-Methyltransferase gene, that codifies a dopamine degradation enzyme active in prefrontal cortex, has been studied as one of the most promising candidates in the etiopathogenesis of schizophrenia, particularly the rs4860 polymorphism (Val158Met). The possible association with an altered prefrontal dopaminergic transmission would be supported by the revised dopaminergic theory. Following this theory, there is a dopaminergic disequilibrium in schizophrenia, with an increase in subcortical D2 dopaminergic transmission and a deficit in D1 cortical stimulation. COMT Val158Met polymorphism has not consistently associated with schizophrenia. The study of endophenotypes and biological markers has suggested associations with cognitive deficits, neurophysiologic and neuroanatomic markers and with clinical phenotypes, such as aggressiveness, suicide, psychotic symptoms, age of onset and clinical response. It also has been reported an interaction with cannabis in the modulation of the risk of psychosis. This heterogeneity could be explained by methodological biases, related to the validity and representativeness of the studied samples and may be solved with the systematic study of epidemiological samples of patients in the initial phases of psychosis. Following the hypothesis of the existence of an altered prefrontal dopaminergic transmission, the Val158 allele in the COMT gene would be associated with more severe psychotic symptoms, particularly negative symptoms and with poor prognostic factors. Likewise, the premorbid use of cannabis could modulate this risk, increasing the risk or counteract the protective factors. The main objective was to study the association between the clinical onset and evolution in the first 6 weeks of treatment and the COMT Val158Met polymorphism as well as the interaction with premorbid cannabis use. The secondary objectives were to study the incidence of schizophrenia and validate the representativeness of the sample, to analyse the relation between the Val158Met polymorphism and clinical symptoms, age of onset, clinical response to treatment and to estimate the presence of gen-environment interactions with the premorbid cannabis use. 174 consecutive first episode psychosis patients with a diagnosis of schizophrenia, schizoaffective disorder, schizophreniform disorder, brief psychotic disorder or psychosis non-otherwise specified were included in the PAFIP program. The program was designed for the detection and treatment of all cases in the region of Cantabria, form February 2001 to February 2005. The patients were assessed with a semi-structured interview, SANS, SAPS, HDRS, CDS, YMRS scales and the SCID-I interview. They were followed up to 6 weeks and treated with a randomly assigned antipsychotic (olanzapine, risperidone or haloperidol). Rs4680 polymorphism was assessed in peripheric blood samples. A first study showed a treated incidence of 1.38/10000 and the association with several risk factors such as age under 25 years, male gender, single marital status, unemployment, primary educational level, urban environment and cannabis use. A second study found an association between the Val158 allele and negative symptoms severity at onset, early age of onset, schizophrenia diagnosis and longer duration of untreated psychosis in females. A third study showed an association between premorbid cannabis use and early age of onset and an interaction between cannabis use and genotype, indicating that the cannabis use counter act the protective effect of the Met158Met allele in age of onset. Finally, in a fourth study the association between the Val158 allele and negative symptoms was confirmed after 6 weeks of treatment, although no relation was found with clinical response. The results showed that the COMT Val158Met polymorphism could be associated with an earlier age of onset and a higher severity of negative symptoms. Likewise, the premorbid use of cannabis was associated with an earlier age of onset and there was found a gene-environmental interaction, deleting the protective effect of the Met158 Allele. These findings suggest the importance of COMT Val158Met polymorphism and premorbid cannabis use in the etiopathogenesis of the schizophrenia that could be explained by a decrease in the prefrontal dopaminergic transmission.
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A Vulnerability-Stress-Coping Model Of Adjustment To The Individual Negative Symptoms Of Schizophrenia

Annette Watson-Luke Unknown Date (has links)
This research program represents the first systematic exploration of the subjective experience of alogia, anhedonia, attention problems, avolition, and emotional blunting, and its relation to other objective and subjective factors in schizophrenia. Using a combined rational-empirical approach, a vulnerability-stress-coping model of adjustment to the 5 negative symptoms was developed and tested. Three aspects of appraisal were examined, the primary appraisals of symptom severity and distress, and the secondary appraisal of control. The dimensions of coping with individual symptoms were initially examined using a rational approach, and then empirically using exploratory factor analyses. The Appraisal and Coping with Negative Symptoms Interview Schedule (ACNSIS) was developed for use in Study 1. Both qualitative and quantitative appraisal and coping data were examined for 20 people with negative symptoms. Responses to the ACNSIS demonstrated that appraisals and coping responses varied across participants and individual negative symptoms. Previously employed categorisations of coping behaviour were used to examine and quantify coping. Negative symptom-specific differences were found in awareness of negative symptom presence, degree of agreement with objective ratings, appraisals, reliance on different types of coping, and relations with participant characteristics. Participant coping responses from Study 1 were used to construct the self-report measure used in subsequent studies. Study 2 involved the development, administration, and evaluation of the self-report Appraisal and Coping with Negative Symptoms Questionnaire (ACNSQ). Both an electronic and paper version of the ACNSQ were developed. The ACNSQ was administered to 120 people with schizophrenia or schizoaffective disorder. Participants were required to make severity, distress and control appraisals for each negative symptom they believed they were suffering from. Following symptom appraisals, a number of symptom-specific and general coping items were presented for each negative symptom. In Study 2A, the multidimensionality of coping responses and the nature of empirically derived subscales were explored individually for each negative symptom. Factor analyses of data from 119 participants resulted in 3 underlying coping dimensions for each symptom. These dimensions, which formed the basis of the ACNSQ coping subscales, were labelled as active, emotional, or avoidant forms of coping. Coping subscales were found to be moderately similar across symptoms. The subscales were shown to be internally consistent and largely independent within symptoms. It was found that the degree of reliance on particular coping subscales was negative symptom-specific, although participant coping was related across symptoms. In Study 2B, the nature of negative symptom appraisals and the psychometric properties of the ACNSQ were examined. There was evidence that the nature of appraisals varied according to negative symptom. Retest reliability analyses indicated that overall, ACNSQ appraisals had a low to moderate degree of reliability while coping subscales demonstrated a moderate to high degree of reliability. Differential associations between appraisal and coping and a range of theoretically related variables provided evidence of the construct validity of the ACNSQ. Study 3 used exploratory techniques to conduct cross-sectional tests of a vulnerability-stress-coping model of adjustment to individual negative symptoms based on the data of the 119 participants. Associations between the objective indicator of negative symptom stressor level, and the subjective experience variables of insight, appraisal and coping were examined in relation to adjustment using a multidimensional approach. Two models of the relations between negative symptom predictors and 3 separate domains of adjustment were investigated. Study 3A provided moderate support for a direct effects model for each of the 5 negative symptoms. Objective negative symptom level, insight, primary appraisals and coping subscales all had significant direct effects on one or more domains of adjustment. In general, higher objective negative symptom levels, higher severity and distress appraisals, and greater reliance on avoidant forms of coping were associated with poorer adjustment. The direct effects of active and emotional forms of coping were less consistent and varied across symptoms and adjustment domains. Study 3B extended these findings by providing a limited amount of support for a mediated effects model. Appraisal and coping were found to act as mediators in some of the relations between objective indicators and subjective experience variables for alogia, attention problems and avolition. There was evidence that the impact of insight on coping was partly mediated by control appraisals. Coping partly mediated the relation between stress and adjustment, and appraisal and adjustment. Overall, this series of exploratory studies make a unique contribution to understanding the subjective experience of the negative symptoms of schizophrenia. The proposed vulnerability-stress-coping model demonstrated utility in identifying variables important in the prediction of adjustment to individual negative symptoms, and in delineating the nature of associations between variables. Further research is required to improve the psychometric properties of the ACNSQ. However, it offers promise as an instrument with which to assess negative symptom appraisals and coping responses, in both clinical and research settings. The present findings have important theoretical and clinical implications concerning the role of subjective and objective factors involved in adjustment to the negative symptoms of schizophrenia. This research program provides a valuable foundation for future research to test the vulnerability-stress-coping model in its entirety.
20

Fonctionnement social et rétablissement à la suite d'un premier épisode psychotique

Bourdeau, Geneviève 12 1900 (has links)
De nos jours, l’idée selon laquelle bon nombre d’individus atteints de psychose peuvent se rétablir sensiblement au fil du temps est de plus en plus répandue. Alors que le milieu médical associe le rétablissement à la rémission symptomatique, les usagers de services en santé mentale le voient plutôt comme un processus où l’absence de symptômes n’est pas une condition sine qua non. Ne s’opposant à ni l’un ni l’autre de ces points de vue, le traitement actuel des psychoses vise le retour à un fonctionnement social approprié. Chez les jeunes atteints d’un premier épisode psychotique, une diminution marquée des symptômes après un traitement pharmacologique se traduit rarement en une amélioration significative du fonctionnement, ce qui justifie la mise en place d’interventions psychosociales. On connait aujourd’hui quelques variables associées au fonctionnement social chez cette population, mais celui-ci a peu été étudié de façon spécifique. De même, on connait mal la manière dont ces jeunes vivent leur rétablissement en tant que processus. Cette thèse porte donc sur le rétablissement et le fonctionnement social de jeunes en début de psychose. La première partie consiste en une introduction aux concepts de rétablissement et de réadaptation, et en une revue de la littérature des interventions psychosociales pouvant favoriser leurs rétablissement et fonctionnement. Plus spécifiquement, nous illustrons comment ces interventions peuvent s’appliquer aux adolescents, clientèle sur laquelle peu de littérature existe actuellement. La deuxième partie présente les résultats d’une étude sur la valeur prédictive de variables sur trois domaines du fonctionnement social de 88 jeunes adultes en début de psychose. Des équations de régression multiple ont révélé qu’un niveau plus élevé de dépression était associé à une vie sociale moins active, qu’un moins bon apprentissage verbal à court terme était associé à un plus bas fonctionnement vocationnel, que le fait d’être de sexe masculin était négativement associé aux habiletés de vie autonome, et qu’un niveau plus élevé de symptômes négatifs prédisait de moins bonnes performances dans les trois sphères du fonctionnement. Finalement, la troisième partie s’intéresse au processus de rétablissement en début de psychose par l’analyse de récits narratifs selon un modèle en cinq stades. Nous avons découvert que l’ensemble de notre échantillon de 47 participants se situaient dans les deux premiers stades de rétablissement lors du premier temps de mesure, et que le fait de se trouver au deuxième stade était associé à de meilleurs scores d’engagement social et de fonctionnement occupationnel, à un meilleur développement narratif, à moins de symptômes négatifs et positifs, et à plus d’années de scolarité. Par ailleurs, l’examen des stades à deux autres temps de mesure a révélé des profils relativement stables sur une période de neuf mois. En somme, les résultats démontrent la nécessité d’évaluer le fonctionnement social de façon plus spécifique et l’importance d’offrir des interventions psychosociales en début de psychose visant notamment le développement des relations et l’intégration scolaire/professionnelle, ou visant à améliorer le faible développement narratif. Cette thèse est, de plus, un premier pas dans l’étude du processus de rétablissement des jeunes atteints de psychose. / Currently, the idea that several individuals experiencing psychosis can show evidence of recovery over time is gaining in popularity. Although recovery is viewed as the disappearance of symptoms in the medical field, consumers of mental health services see it more as process in which the complete absence of symptoms is not a sine qua non. Nevertheless, the current treatment for psychosis is aimed at regaining a satisfactory level of social functioning. In individuals experiencing a first psychotic episode, a noticeable decrease in symptoms is rarely associated with a significant improvement in functioning. Therefore, psychosocial interventions are necessary to assist in recovery. The literature has identified a number of variables associated with social functioning in this population, but to date, there are no studies investigating this aspect in details. Furthermore, very little is known about how these youth experience the process of recovery. This thesis dissertation will therefore address recovery and social functioning in young people experiencing a first episode of psychosis. A first section will serve as an introduction to the concepts of recovery and rehabilitation and a review of the literature on psychosocial interventions promoting recovery and functioning. Specifically, we will illustrate how these interventions can apply to adolescents, a population for which very few studies have been published. A second section will present the results of a study on the predictive value of variables on three domains of social functioning in 88 young adults in early psychosis. Multiple regression analyses showed that a more severe depression was associated with a less active social life; that a poorer short term verbal learning ability was associated with poorer vocational functioning; and that men showed poorer independent living skills. Furthermore, more severe negative symptoms were associated with poorer performances in all three spheres of social functioning. Finally, the third section will address the recovery process in early psychosis through the analysis of narratives using a five stage recovery model. We determined that overall, our sample of 47 individuals were classified within the first two stages of recovery at baseline and that those classified in the second stage showed better social engagement and vocational functioning scores, a better narrative development, less severe positive and negative symptoms, and had attained a higher educational level. Furthermore, the analysis of the stages of recovery across two others time points show that these profiles are relatively stable over a 9 month period. In conclusion, these results show that it is necessary to evaluate social functioning in a more detailed manner, and reaffirms the importance of making psychosocial interventions available to service users experiencing early psychosis. It highlights, in particular, the need for services aimed towards the development of social relationships and educational/vocational integration, or interventions addressing deficits in narrative development. Moreover, this thesis dissertation is a first step towards the study of the recovery process of young adults experiencing psychosis.

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