Editorial: Demystifying the Placebo Effect.
Editorial: Demystifying the Placebo Effect.
复制标题
社论：揭秘安慰剂效应。
DOI：
10.1093/aje/kwaa162
复制
发表时间：
2021
影响因子：
5
通讯作者：
Murray,EleanorJ
中科院分区：
文献类型：
--
作者：
Murray,EleanorJ
安慰剂效应是一个诱人的概念，至少从1955年开始就引起了公众的关注，当时亨利比彻（1）对15项大型研究（总n= 1，082例患者）的证据进行了编目，并得出结论，35.5%的患者（100%）的安慰剂效应是由安慰剂效应引起的。（±2.2%）的个体对安慰剂有“应答”。初读之下，比彻提出的结果似乎是可信的。安慰剂在医学研究中的目标通常被描述为“区分药理作用和暗示的作用......”并获得对实验结果的公正评价”（1，第1602页）。这一目标的内在要求是，所有的医疗干预都可能有某种通过心理机制运作的因果效应，这种效应的强度与干预模式无关（2，3）。然而，由于没有明确阐明这种因果关系的性质，我们不能反驳或支持这种效应的存在。因果推理的反事实或潜在结果框架（4）声明如果每个人接受暴露或治疗的结果的预期值平均不同于相同个体接受暴露或治疗的结果的预期值，则暴露对结果具有因果影响其他暴露或治疗（4）。在关于安慰剂效应的讨论中，这一框架的一个关键要素常常被遗漏，那就是要求指定其他感兴趣的暴露或治疗。正如我们将看到的，在安慰剂组中省略一个明确的非安慰剂对照组，会在安慰剂效应和“安慰剂反应”的定义和估计中引入不切实际的假设、混淆和虚假的发现。
Placebo effects are a tantalizing concept that have captured public attention since at least 1955, when Henry Beecher (1) cataloged evidence across 15 large studies (total n= 1,082 patients) and concluded that 35.5.%(±2.2%) of individuals “respond” to placebo. The results presented by Beecher seem plausible at first read. The goal of placebos in medical research is often described as “to distinguish pharmacological effects from the effects of suggestion... and to obtain an unbiased assessment of the result of experiment”(1, p. 1602). Inherent in this goal is a claim that all medical interventions might have some causal effect that operates via psychological mechanisms and that the strength of such an effect is independent of the mode of intervention (2, 3). However, without clearly articulating the nature of this causal effect, we cannot refute or support the existence of this effect.The counterfactual or potential outcome framework for causal inference (4) states that an exposure has a causal effect on an outcome if the expected value of the outcome had everyone received that exposure or treatment is on average different from the expected value of the outcome had those same individuals received some other exposure or treatment (4). A key element of this framework often missing from the conversation about placebo effects is the requirement to specify the other exposure or treatment of interest. As we shall see, the omission of an explicit nonplacebo comparison group for the placebo group introduces unrealistic assumptions, confusion, and spurious findings into the definition and estimation of the placebo effect and “placebo response.”