Efficacy of open‐label counterconditioning for reducing nocebo effects on pressure pain

Abstract

Nocebo effects can adversely affect the experience of physical symptoms, such as pain and itch. Nocebo effects on itch and pain have shown to be induced by conditioning with thermal heat stimuli and reduced by counterconditioning. However, open-label counterconditioning, in which participants are informed about the placebo content of the treatment, has not been investigated, while this can be highly relevant for clinical practice. Furthermore, (openlabel) conditioning and counterconditioning has not been investigated for pain modalities relevant to musculoskeletal disorders, such as pressure pain.In a randomized controlled trial, we investigated in 110 healthy female participants whether nocebo effects on pressure pain combined with open-label verbal suggestions can be 1) induced via conditioning and 2) reduced via counterconditioning. Participants were allocated to either a nocebo or sham conditioning group. Next, the nocebo group was allocated to either counterconditioning, extinction, or continued nocebo conditioning; sham conditioning was followed by placebo conditioning. Nocebo effects were significantly larger after nocebo conditioning than sham conditioning (d = 1.27). Subsequently, a larger reduction of the nocebo effect was found after counterconditioning than after extinction (d = .99) and continued nocebo conditioning (d = 1.63), with effects similar to placebo conditioning (following sham conditioning). These results show that (counter)conditioning combined with open-label suggestions can modulate nocebo effects on pressure pain, which provides promise in designing learning-based treatments to reduce nocebo effects in patients with chronic pain disorders, particularly for musculoskeletal disorders.