Jagiellonian University, Institute of Psychology, Pain Research Group, Kraków, Poland.
The Jerzy Kukuczka Academy of Physical Education, Department of Kinesiotherapy and Special Methods in Physiotherapy, Katowice, Poland.
Pain Med. 2018 Jun 1;19(6):1156-1169. doi: 10.1093/pm/pnx177.
To investigate the influence of expectancy of pain intensity, fear of pain (trait), and fear (state) on the effectiveness of hidden and open conditioning to produce placebo analgesia.
A total of 90 healthy female volunteers were randomly assigned to three groups (hidden conditioning, open conditioning, and control) that received electrical stimuli preceded by either orange or blue lights. One color was paired with painful stimuli (control stimuli) and the other color was paired with nonpainful stimuli (conditioned stimuli) in both the hidden and open conditioning groups. Only participants in the open conditioning group were informed about this association. In the control group, both color lights were followed by control stimuli. In the testing phase, both colored lights were followed by identical control stimuli. Participants rated pain intensity, expectancy of pain intensity, fear, and fear of pain.
A significant analgesic effect was found only in the hidden conditioning group, where no explicit verbal suggestions were provided. Hidden conditioning had an effect on expectancy and fear-participants in the hidden conditioning group expected less pain and experienced less fear in relation to conditioned stimuli. Fear was the only predictor of placebo analgesia in the hidden conditioning group. Neither expectancy of pain intensity nor fear of pain predicted placebo analgesia.
Fear seems to be a more important factor than expectancy in producing placebo analgesia induced by hidden conditioning.
探究疼痛强度预期、疼痛恐惧（特质）和疼痛恐惧（状态）对产生安慰剂镇痛的隐藏和开放条件作用的影响。
共纳入 90 名健康女性志愿者，随机分为三组（隐藏条件组、开放条件组和对照组），三组均接受电刺激，刺激前先呈现橙色或蓝色灯光。在隐藏和开放条件组中，一种颜色与疼痛刺激（对照刺激）相关联，另一种颜色与无痛刺激（条件刺激）相关联。只有开放条件组的参与者被告知这种关联。在对照组中，两种颜色的灯光后均呈现对照刺激。在测试阶段，两种颜色的灯光后均呈现相同的对照刺激。参与者评估疼痛强度、疼痛强度预期、恐惧和疼痛恐惧。
仅在未提供明确口头暗示的隐藏条件组中观察到显著的镇痛效果。隐藏条件作用于预期和恐惧——隐藏条件组的参与者对条件刺激的预期疼痛程度较低，恐惧程度较低。在隐藏条件组中，恐惧是安慰剂镇痛的唯一预测因素。疼痛强度预期和疼痛恐惧均不能预测安慰剂镇痛。
在隐藏条件作用下产生的安慰剂镇痛中，恐惧似乎比预期更重要。
