Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland.
Institute for Emotion-Focused Therapy, Roskilde, Denmark.
Sci Rep. 2023 Feb 14;13(1):2624. doi: 10.1038/s41598-023-29624-7.
Placebos have been shown to be beneficial for various conditions even if administered with full transparency. Hence, so-called open-label placebos (OLPs) offer a new way to harness placebo effects ethically. To take this concept one step further, this study aimed at evaluating placebo effects without the use of a physical placebo, i.e., by imagining taking a pill. Healthy students (N = 173) with self-reported test anxiety were either randomized to an imaginary pill (IP; n = 55), an OLP (n = 59) or a control group (CG; n = 59). Both intervention groups were instructed to take two pills daily for three weeks. Primary outcome was test anxiety, secondary outcomes were sleep quality, general well-being and test performance. Groups test anxiety differed at study-endpoint, F(2,169) = 11.50, p < .001. Test anxiety was lower in the intervention groups compared to the CG, t(169) = - 4.44, p < .001, d = - 0.71. The interventions did not differ significantly, i.e., both were similarly efficacious, t(169) = 0.61, p = .540, d = 0.11. The interaction between group and time in explaining test anxiety was significant, F(5,407.93) = 6.13, p < .001. OLPs and IPs reduced test anxiety in healthy participants compared to the CG. This finding opens the door for a novel and ethical method to harness placebo effects.
安慰剂即使在完全透明的情况下也已被证明对各种病症有益。因此，所谓的开放性安慰剂（OLP）提供了一种新的合乎伦理地利用安慰剂效应的方法。为了更进一步地实现这一概念，本研究旨在评估无需使用物理安慰剂（即想象服用药丸）的安慰剂效应。有自我报告考试焦虑的健康学生（N=173）被随机分为想象药丸组（IP；n=55）、开放性安慰剂组（OLP；n=59）或对照组（CG；n=59）。两个干预组均被指示每日服用两片，持续三周。主要结果是考试焦虑，次要结果是睡眠质量、总体幸福感和考试表现。三组在研究终点时的考试焦虑程度不同，F(2,169)=11.50，p<0.001。与 CG 相比，干预组的考试焦虑程度较低，t(169)=-4.44，p<0.001，d=-0.71。干预措施之间没有显著差异，即两者的疗效相当，t(169)=0.61，p=0.540，d=0.11。解释考试焦虑的组间和时间间的交互作用具有统计学意义，F(5,407.93)=6.13，p<0.001。OLP 和 IP 可降低健康参与者的考试焦虑程度，与 CG 相比。这一发现为利用安慰剂效应提供了一种新颖而合乎伦理的方法。
