Classical conditioning and expectancy in placebo hypoalgesia: A randomized controlled study in patients with atopic dermatitis and persons with healthy skin
Classical conditioning and expectancy in placebo hypoalgesia: A randomized controlled study in patients with atopic dermatitis and persons with healthy skin
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DOI：
10.1016/j.pain.2006.08.025
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发表时间：
2007-03-01
期刊：
影响因子：
7.4
通讯作者：
Worm, Margitta
中科院分区：
文献类型：
--
作者：
Klinger, Regine;Soost, Stephanie;Worm, Margitta
安慰剂的有效性未受到质疑。然而，目前还不清楚安慰剂效应是基于哪些机制。除了期望理论，经典条件反射被认为是一个主要的解释模型。在一项实验性条件设计中，我们测试了96名参与者，其中48名患有特应性皮炎（24名男性，24名女性），48名皮肤健康（24名男性和24名女性）。所有受试者都接受了不同简介的中性软膏（“减轻疼痛软膏”与“中性软膏”）。随后施加电疼痛刺激，其选择性地诱导疼痛感。在学习条件（经典条件反射）的情况下，参与者不知道，疼痛刺激的强度在涂抹药膏后降低了50%。该研究解决了特应性皮炎患者经历的疼痛是否可以通过安慰剂效应减少的问题，以及安慰剂效应是通过预期还是通过经典条件反射过程或两者兼而有之来实现的。结果表明，安慰剂效应是通过期望和经典条件反射实现的。然而，调节过程似乎是必要的，以获得更持久的效果。这种影响的程度似乎是更大的过敏症比健康对照组。通过口头指令实现的期望也可以被视为一种条件刺激，它重新激活了早期的刺激联想。(c)2006年国际疼痛研究协会。Elsevier B.V.出版，保留所有权利。
The effectiveness of placebos is unchallenged. However, it is still not clear on which mechanisms the placebo effect is based. Besides expectancy theories, classical conditioning is discussed as a major explanatory model. In an experimental conditioning design we tested 96 participants, 48 with atopic dermatitis (24 male, 24 female) and 48 with healthy skin (24 male and 24 female). All of them received a neutral ointment with a different briefing ("pain-reducing ointment" versus "neutral ointment"). Electrical pain stimuli were subsequently applied, which selectively induce a painful sensation. In the case of the learning condition (classical conditioning) and unbeknown to the participants, the intensity of the pain stimulus was reduced by 50% after the ointment had been applied. The study addressed the question whether the pain experienced by the patients with atopic dermatitis could be reduced through a placebo effect and whether the placebo effect was achieved through expectancy or through a process of classical conditioning or both. The results indicate that a placebo effect is achieved via expectancy and classical conditioning. However, conditioning processes seem to be necessary for a longer lasting effect. The extent of this effect seemed to be greater in atopics than in healthy controls. Expectancy, achieved through verbal instruction, might also be seen as a conditioned stimulus that reactivates earlier stimulus associations. (c) 2006 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.