Jagiellonian University, Institute of Psychology, Pain Research Group, Kraków, Poland.
SWPS University of Social Sciences and Humanities, Katowice, Poland.
Pain. 2021 Aug 1;162(8):2237-2245. doi: 10.1097/j.pain.0000000000002211.
In most experimental studies in which verbal suggestion and classical conditioning are implemented together to induce placebo effects, the former precedes the latter. In naturally occurring situations, however, the information concerning pain does not always precede but often follows the pain experience. Moreover, this information is not always congruent with experience. This study investigates whether the chronology of verbal suggestion and conditioning, as well as their congruence, affects placebo hypoalgesia and nocebo hyperalgesia. The effects induced in 15 groups were compared. The participants in 8 experimental groups were presented with verbal suggestions that were either congruent or incongruent with classical conditioning. The verbal suggestions were provided either before or after conditioning. In 2 other experimental groups, placebo conditioning or nocebo conditioning was implemented without any verbal suggestion; in 2 groups, verbal suggestion of hypoalgesia or hyperalgesia without conditioning was applied. The control groups without any suggestions or conditioning were also included. Placebo hypoalgesia induced by congruent procedures was significantly stronger when the suggestion of hypoalgesia preceded rather than followed conditioning. The order of the congruent procedures did not affect the magnitude of nocebo hyperalgesia. In the groups in which incongruent procedures were implemented, placebo hypoalgesia or nocebo hyperalgesia was in line with the direction of the last-used procedure, regardless of whether it was conditioning or verbal suggestion. The results show that not the type of the procedure (verbal suggestion or conditioning), but the direction of the last-used procedure shapes pain-related expectancies and determines placebo effects.
在大多数将言语暗示和经典条件作用结合起来诱导安慰剂效应的实验研究中，前者先于后者。然而，在自然发生的情况下，关于疼痛的信息并不总是先于疼痛体验，而是经常紧随其后。此外，这种信息并不总是与体验一致。本研究调查言语暗示和条件作用的时间顺序及其一致性是否会影响安慰剂镇痛和反安慰剂痛觉过敏。比较了 15 组的效果。在 8 个实验组中，参与者接受了与经典条件作用一致或不一致的言语暗示。这些言语暗示是在条件作用之前或之后提供的。在另外两个实验组中，没有进行言语暗示，而是进行了安慰剂条件作用或反安慰剂条件作用；在另外两个实验组中，没有进行条件作用，而是应用了镇痛或镇痛的言语暗示。还包括没有任何暗示或条件作用的对照组。当镇痛暗示先于条件作用而不是后于条件作用时，一致程序引起的安慰剂镇痛作用明显更强。一致程序的顺序不影响反安慰剂痛觉过敏的程度。在实施不一致程序的组中，无论最后使用的程序是条件作用还是言语暗示，安慰剂镇痛或反安慰剂痛觉过敏都与最后使用的程序的方向一致。结果表明，不是程序的类型（言语暗示或条件作用），而是最后使用的程序的方向塑造了与疼痛相关的期望，并决定了安慰剂效应。
