Placebo似乎没有想像中那麽大的效果。 Cochrane Library 的一篇Review： 《Placebo interventions for all clinical conditions》 （http://www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/ CD003974/frame.html 缩址：http://0rz.tw/LUu02 ） Abstract： Plain language summary It has been widely believed that placebo (dummy) treatments (for example sugar tablets) are associated with substantial effects on a wide range of health problems. However, this belief is not based on evidence from randomised trials that use a placebo treatment for one group of people, while another group receives no treatment. The effect of placebo treatments was studied by reviewing more than 150 such trials covering many types of healthcare problems. Placebo treatments caused no major health benefits, although they possibly had a small effect on outcomes reported by patients, for example pain. Background Placebo interventions are often claimed to improve patient-reported and observer-reported outcomes, but this belief is not based on evidence from randomised trials that compare placebo with no treatment. Objectives To assess the effect of placebo interventions. Search strategy We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2002), MEDLINE (1966 to 2002), EMBASE (1980 to 2002), Biological Abstracts (1986 to 2002), and PsycLIT (1887 to 2002). We contacted experts on placebo research, and read references in the included trials. Selection criteria We included randomised placebo trials with a no-treatment control group investigating any health problem. Data collection and analysis Two review authors independently assessed trial quality and extracted data. We contacted study authors for additional information. Main results Outcome data were available in 156 out of 182 included trials, investigating 46 clinical conditions. We found no statistically significant pooled effect of placebo in 38 studies with binary outcomes (4284 patients), relative risk 0.95 (95% confidence interval (CI) 0.89 to 1.01). The pooled relative risk for patient-reported outcomes was 0.95 (95% CI 0.88 to 1.03) and for observer-reported outcomes 0.91 (95% CI 0.81 to 1.03). There was heterogeneity (P=0.01) but the funnel plot was symmetrical. There was no statistically significant effect of placebo interventions in the four clinical conditions investigated in three trials or more: pain, nausea, smoking, and depression, but confidence intervals were wide. We found an overall effect of placebo treatments in 118 trials with continuous outcomes (7453 patients), standardised mean difference (SMD) -0.24 (95% CI -0.31 to -0.17). The SMD for patient-reported outcomes was -0.30 (95% CI -0.38 to -0.21), whereas no statistically significant effect was found for observer-reported outcomes, SMD -0.10 (95% CI -0.20 to -0.01). There was heterogeneity (P<0.001) and large variability in funnel plot results even for big trials. There was an apparent effect of placebo interventions on pain (SMD -0.25 (95% CI -0.35 to-0.16)), and phobia (SMD -0.63 (95% CI -1.17 to -0.08)); but also a substantial risk of bias. There was no statistically significant effect of placebo interventions in eight other clinical conditions investigated in three trials or more: nausea, smoking, depression, overweight, asthma, hypertension, insomnia and anxiety, but confidence intervals were wide. Authors' conclusions There was no evidence that placebo interventions in general have clinically important effects. A possible small effect on continuous patient-reported outcomes, especially pain, could not be clearly distinguished from bias. -- 看哪，这论证是极好的：苏格拉底是人，凡造物都难免要朽坏，所以末了我们知道，苏格 拉底总要落到死里面了。从亚里士多德以来的每一个逻辑学家，没有一个不欢喜这个论证 的。亚里士多德明白的告诉了我们论证形式的道理，因了这个缘故，我们便尊他为逻辑学 的王。 --

※ 发信站: 批踢踢实业坊(ptt.cc) ※ 编辑: daze 来自: 140.112.212.171 (03/26 02:28) 有些study有"给药"、"给Placebo"、"no treatment"三个组。 然後被这篇拿出Placebo跟no treatment的资料做分析。 ※ 编辑: daze 来自: 140.112.212.171 (03/26 03:34)