Department of Clinical Psychology and Psychotherapy, Georg-Elias-Müller-Institute for Psychology, University of Göttingen, Göttingen.
Clinical and Biological Psychology, Catholic University Eichstätt-Ingolstadt, Eichstätt, Germany.
Clin J Pain. 2019 Sep;35(9):737-743. doi: 10.1097/AJP.0000000000000734.
Nocebo hyperalgesia is an increase in pain through the expectation of such an increase as a consequence of a sham treatment. Nocebo hyperalgesia can be induced by observation of a model demonstrating increased pain via verbal pain ratings. The aim of the present study was to investigate whether observing natural pain behavior, such as facial pain expressions, can also induce nocebo responses.
Eighty female participants (age: 22.4 y±4.8) underwent a pressure-pain procedure (algometer) on both hands and rated their pain on a numerical rating scale. All participants received ointment on one of their hands, but no explanation was given for this. Before their own participation, the participants watched a video in which a woman underwent the same procedure and who either modeled increased pressure pain upon ointment application (nocebo condition) or showed a neutral facial expression throughout (control condition).
A 2×2 analysis of variance with condition (nocebo; control) as a between-subjects factor and ointment application (with; without) as a within-subject factor revealed a main effect for ointment and a condition×ointment interaction. In the nocebo condition, pain ratings were higher with ointment than without.
For the first time, it was shown that watching a model demonstrating pain through facial expressions induced nocebo hyperalgesia. As we mostly express pain through natural pain behavior rather than through pain ratings, this paradigm extends our knowledge of observational learning about pain and may have implications for contexts in which persons watch others undergo painful procedures.
非安慰剂性痛觉过敏是指由于对模拟治疗的预期而导致的疼痛增加。非安慰剂性痛觉过敏可以通过观察通过口头疼痛评分显示疼痛增加的模型来诱发。本研究的目的是研究观察自然疼痛行为（如面部疼痛表情）是否也能引起非安慰剂反应。
80 名女性参与者（年龄：22.4±4.8 岁）在手的两侧接受了压力疼痛程序（测痛计），并用数字评分量表对疼痛进行了评分。所有参与者的一只手上都涂了软膏，但没有对此进行解释。在自己参与之前，参与者观看了一段视频，视频中一名女性接受了相同的程序，她在涂抹软膏时表现出增加的压力疼痛（非安慰剂条件）或整个过程中表现出中性的面部表情（对照条件）。
条件（非安慰剂；对照）作为被试间因素和软膏应用（有；无）作为被试内因素的 2×2 方差分析显示了软膏的主效应和条件×软膏的交互作用。在非安慰剂条件下，涂抹软膏后的疼痛评分高于不涂抹软膏的情况。
这是首次表明，观察通过面部表情表现出疼痛的模型会引起非安慰剂性痛觉过敏。由于我们主要通过自然的疼痛行为而不是通过疼痛评分来表达疼痛，这种范式扩展了我们对疼痛观察学习的认识，并可能对人们观察他人接受痛苦程序的情况产生影响。
