Meeuwis Stefanie H, van Middendorp Henriët, van Laarhoven Antoinette I M, van Leijenhorst Cora, Pacheco-Lopez Gustavo, Lavrijsen Adriana P M, Veldhuijzen Dieuwke S, Evers Andrea W M
Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, P.O. Box 9555, 2300RB, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, P.O. Box 9600, 2300RC, Leiden University Medical Center, Leiden, the Netherlands.
Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, P.O. Box 9555, 2300RB, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, P.O. Box 9600, 2300RC, Leiden University Medical Center, Leiden, the Netherlands.
Neurosci Biobehav Rev. 2020 Jun;113:325-337. doi: 10.1016/j.neubiorev.2020.03.025. Epub 2020 Mar 30.
Placebo and nocebo effects can influence somatic symptoms such as pain. For itch and other dermatological symptoms these effects have been far less investigated. This review systematically integrates evidence from both animal (mainly rodents) and human trials on placebo and nocebo effects in itch, itch-related symptoms and conditions of the skin and mucous membranes, and related immune outcomes (e.g., histamine). Thirty-one animal studies, and fifty-five human studies (k = 21 healthy participants, k = 34 patients) were included. Overall, studies consistently show that placebo and nocebo effects can be induced by various methods (e.g., suggestions, conditioning and social cues), despite high heterogeneity across studies. Effects of suggestions were found consistently across subjective and behavioral parameters (e.g., itch and scratching in humans), whereas conditioning was likely to impact physiological parameters under certain conditions (e.g., conditioning of histamine levels in stressed rodents). Brain areas responsible for itch processing were associated with nocebo effects. Future research may investigate how variations in methods impact placebo and nocebo effects, and whether all symptoms and conditions can be influenced equally.
安慰剂和反安慰剂效应可影响疼痛等躯体症状。对于瘙痒及其他皮肤症状，这些效应的研究则少得多。本综述系统整合了来自动物（主要是啮齿动物）和人体试验的证据，这些证据涉及瘙痒、与瘙痒相关的症状以及皮肤和黏膜状况中的安慰剂和反安慰剂效应，以及相关的免疫结果（如组胺）。纳入了31项动物研究和55项人体研究（k = 21名健康参与者，k = 34名患者）。总体而言，尽管各研究之间存在高度异质性，但研究一致表明，安慰剂和反安慰剂效应可通过多种方法（如暗示、条件作用和社会线索）诱发。在主观和行为参数（如人类的瘙痒和搔抓）方面始终发现了暗示效应，而条件作用在某些情况下可能会影响生理参数（如应激啮齿动物组胺水平的条件作用）。负责瘙痒处理的脑区与反安慰剂效应有关。未来的研究可以调查方法的变化如何影响安慰剂和反安慰剂效应，以及是否所有症状和状况都能受到同等程度的影响。
