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1.
Braz. J. Psychiatry (São Paulo, 1999, Impr.) ; 41(4): 336-362, July-Aug. 2019. tab, graf
Artigo em Inglês | LILACS-Express | ID: biblio-1011505

RESUMO

Objectives: Brain imaging studies carried out in patients suffering from generalized anxiety disorder (GAD) have contributed to better characterize the pathophysiological mechanisms underlying this disorder. The present study reviews the available functional and structural brain imaging evidence on GAD, and suggests further strategies for investigations in this field. Methods: A systematic literature review was performed in PubMed, PsycINFO, and Google Scholar, aiming to identify original research evaluating GAD patients with the use of structural and functional magnetic resonance imaging as well as diffusion tensor imaging. Results: The available studies have shown impairments in ventrolateral and dorsolateral prefrontal cortex, anterior cingulate, posterior parietal regions, and amygdala in both pediatric and adult GAD patients, mostly in the right hemisphere. However, the literature is often tentative, given that most studies have employed small samples and included patients with comorbidities or in current use of various medications. Finally, different methodological aspects, such as the type of imaging equipment used, also complicate the generalizability of the findings. Conclusions: Longitudinal neuroimaging studies with larger samples of both juvenile and adult GAD patients, as well as at risk individuals and unaffected relatives, should be carried out in order to shed light on the specific biological signature of GAD.

2.
J Affect Disord ; 259: 21-26, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31437696

RESUMO

BACKGROUND: About one third of patients treated with antidepressant do not show sufficient symptoms relief and up to 15% of patients remain symptomatic even after multiple trials are applied, configuring a state called treatment resistant depression (TRD). A clear definition of this state and the understanding of underlying mechanisms contributing to chronic disability caused by major depressive disorder is still unknown. Therefore, Machine Learning (ML) techniques emerged in the last years as interesting approaches to deal with such complex problems. METHODS: We performed a bibliographic search on Pubmed, Google Scholar and Medline of clinical, imaging, genetic and EEG ML classification studies on treatment-responding depression and TRD as well as studies trying to predict response to a specific treatment in already established TRD. The inclusion criteria were met by eleven studies. Seven focused on the definition of predictors of TRD onset while four attempted to predict the response to specific treatments in TRD. RESULTS: The results showed that it seems possible to classify between responders MDD and TRD with good accuracies based on clinical variables. Moreover, some studies reported the possibility of using EEG measures to predict response to different pharmacological and non-pharmacological treatments in established TRD. LIMITATIONS: The definition of TRD, the selection of variables together with ML algorithms and pipelines varies across the studies, ultimately determining the unfeasibility to implement these models in clinical practice. CONCLUSIONS: The findings suggest that ML could be a valid approach to increase our understanding of TRD and to better classify and stratify this disorder, which may ultimately help clinicians in the assessment of major depressive disorders.

3.
Braz J Psychiatry ; 41(4): 336-362, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31116259

RESUMO

OBJECTIVES: Brain imaging studies carried out in patients suffering from generalized anxiety disorder (GAD) have contributed to better characterize the pathophysiological mechanisms underlying this disorder. The present study reviews the available functional and structural brain imaging evidence on GAD, and suggests further strategies for investigations in this field. METHODS: A systematic literature review was performed in PubMed, PsycINFO, and Google Scholar, aiming to identify original research evaluating GAD patients with the use of structural and functional magnetic resonance imaging as well as diffusion tensor imaging. RESULTS: The available studies have shown impairments in ventrolateral and dorsolateral prefrontal cortex, anterior cingulate, posterior parietal regions, and amygdala in both pediatric and adult GAD patients, mostly in the right hemisphere. However, the literature is often tentative, given that most studies have employed small samples and included patients with comorbidities or in current use of various medications. Finally, different methodological aspects, such as the type of imaging equipment used, also complicate the generalizability of the findings. CONCLUSIONS: Longitudinal neuroimaging studies with larger samples of both juvenile and adult GAD patients, as well as at risk individuals and unaffected relatives, should be carried out in order to shed light on the specific biological signature of GAD.


Assuntos
Transtornos de Ansiedade/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Neuroimagem Funcional , Imagem por Ressonância Magnética , Transtornos de Ansiedade/fisiopatologia , Encéfalo/fisiopatologia , Humanos
4.
Bipolar Disord ; 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30506616

RESUMO

OBJECTIVES: Psychotic symptoms are a common feature in bipolar disorder (BD), especially during manic phases, and are associated with a more severe course of illness. However, not all bipolar subjects experience psychosis during the course of their illness, and this difference often guides assessment and pharmacological treatment. The aim of the present study is to elucidate, for the first time, the FDG uptake dysfunctions associated with psychosis in BD patients with and without a history of past psychotic symptoms, through a positron emission tomography (PET) approach. METHODS: Fifty BD patients with lifetime psychotic symptoms, 40 BD patients without lifetime psychotic symptoms and 27 healthy controls (HC) were recruited and underwent an 18F-FDG-PET session. RESULTS: Compared to HC, BD subjects shared common FDG uptake deficits in several brain areas, including insula, inferior temporal gyrus and middle occipital gyrus. Moreover, we found that BD patients with a history of past psychotic symptoms had a unique FDG uptake alteration in the right fusiform gyrus compared to both BD patients without lifetime psychotic symptoms and HC (all P < 0.01, cFWE corrected). CONCLUSIONS: Overall, our results suggest that FDG uptake alterations in brain regions involved in emotion regulation are a key feature of BD, regardless the presence of past psychosis. Finally, we demonstrated that the FDG uptake reduction in fusiform gyrus is associated with the presence of past psychotic symptoms in BD, ultimately leading towards the idea that the fusiform gyrus might be considered a putative biomarker of psychosis.

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