Navegando por Palavras-chave "placebo effect"
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- ItemSomente MetadadadosConditioning to injection procedures and repeated testing increase SCH 23390-induced catalepsy in mice(Elsevier B.V., 1999-11-01) Chinen, Cibele Cristina [UNIFESP]; Frussa Filho, Roberto [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)The cataleptic behavior induced by the dopamine D-1 antagonist SCH 23390 (SCH) has proven to be a useful assay for investigating the sensitivity of D-1-like dopamine receptor-mediated effects during chronic drug administration. A fundamental flaw in most of these studies may be the involvement of the repeated measures effect, a behavioral phenomenon well demonstrated for neuroleptic-induced catalepsy but not yet investigated for dopamine D-2 antagonists. in this study, mice exposed for various sessions to the bar test presented a strong sensitization to the cataleptic behavior induced by repeated SCH treatment. Conversely, single tested animals exhibited a trend toward decreased catalepsy after repeated SCH treatment, which was in line with the development of a D-1-like dopamine receptor supersensitivity suggested by an increase in SKF 38393-induced grooming behavior. Surprisingly, a challenge intraperitoneal saline injection increased the cataleptic behavior of single tested mice after long-term SCH treatment. This injection-conditioned catalepsy was also observed after repented treatment with the dopamine D-2 antagonists, haloperidol and metoclopramide. While these findings seem to explain some important contradictory data in the literature, they provide a new and simple animal model of the placebo effect. [Neuropsychopharmacology 21:670-678,1999] (C) 1999 American College of Neuropsychopharmacology. Published by Elsevier Science Inc.
- ItemSomente MetadadadosIt Makes Me Feel So Good: An Experimental Study of the Placebo Effect Generated by Brands(Routledge Journals, Taylor & Francis Ltd, 2017) Alves, Carlos Alberto; Lopes, Evandro Luiz [UNIFESP]; da Costa Hernandez, Jose MauroThe placebo effect is the observed result in an individual or group of individuals, after a treatment in which a placebo was used. The results, from two experiments, indicate that in a state of placebo effect, with high motivation and high expectations, the responses (subjective and objective) were improved when a recognized brand was evaluated. We also identified that high expectation levels eliminated the impact of motivation in the relationship between brand and subjective and objective responses and, in that context, any brand would positively influence the dependent variables.
- ItemSomente MetadadadosPlacebo and modafinil effect on sleepiness in obstructive sleep apnea(Elsevier B.V., 2008-02-15) Bittencourt, Lia Rita A. [UNIFESP]; Lucchesi, Ligia M. [UNIFESP]; Rueda, Adriana D. [UNIFESP]; Garbuio, Silvério Aparecido [UNIFESP]; Palombini, Luciana O. [UNIFESP]; Guilleminault, Christian; Tufik, Sergio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Stanford UnivIntroduction: Previous studies have evaluated the effect of modafinil on residual excessive daytime sleepiness (EDS) in patients with obstructive sleep apnea syndrome (OSAS) under effective CPAP treatment. Even though those trials also used placebo groups, we suppose that the placebo effect might influence the patients' response to modafinil.Methods: Twenty sleepy patients with OSAS under CPAP treatment were selected. All of them had Epworth Sleepiness Scale (ESS) > 10. Following baseline evaluation (T1), all subjects were instructed to take placebo for 7 days. After this single-blind placebo phase and second evaluation (T2), patients were randomly allocated to placebo or modafinil treatment for 21 days in a double-blind protocol. Patients underwent a final evaluation (T3) on the last day of drug intake. the evaluations at T1, T2 and T3 consisted of. medical and laboratory examinations, nocturnal polysomnography, ESS, maintenance of wakefulness test (MWT) and complex reaction time (CRT-NY). in addition, in T2 and T3 the change of illness severity scale (CGI-C) and the evaluation of quality of life. (SF-36) were applied.Results: the comparison between the two groups during the three periods studied, showed the following results: in the modafinil group, ESS score did not change during the initial placebo period, but there was a significant reduction during the modafinil treatment period (p=0.0006); in the placebo group a significant reduction occurred during the initial placebo period (p=0.05), and no further change was observed in the treatment (placebo) period. A significant difference was found between the two groups after the placebo period (T2) (p=0.02). Three patients (33%) of the modafinil group and 9 patients (81%) of the placebo group were classified as placebo-responsive (X-2 : p=0.039). in the treatment period, reaction time was significantly reduced in the modafinil group compared to the placebo group (p<0.02). There was a trend toward improvement in overall clinical condition and also in some domains of SF-36 in the modafinil group.Conclusion: in summary, our study confirms that modafinil used adjunctively with CPAP therapy improves subjective daytime sleepiness in patients with OSAS who were regular users of CPAP therapy but still experienced sleepiness. Moreover, it could help in the improvement of objective measures of behavioral alertness and reduce functional impairments. the usefulness of a blinded placebo period for systematic investigation of placebo role in studies based on subjective response is a point that should be considered in this type of drug trial. (c) 2007 Elsevier Inc. All rights reserved.