Testing a positive-affect induction to reduce verbally induced nocebo hyperalgesia in an experimental pain paradigm.

There is an ethical obligation to notify individuals about potential pain associated with diagnoses, treatments, and procedures; however, supplying this information risks inducing nocebo hyperalgesia. Currently, there are few empirically derived strategies for reducing nocebo hyperalgesia. Because nocebo effects are linked to negative affectivity, we tested the hypothesis that a positive-affect induction can disrupt nocebo hyperalgesia from verbal suggestion. Healthy volunteers (N = 147) were randomly assigned to conditions in a 2 (affect induction: positive vs neutral) by 2 (verbal suggestion: no suggestion vs suggestion of pain increase) between-subjects design. Participants were induced to experience positive or neutral affect by watching movie clips for 15 minutes. Next, participants had an inert cream applied to their nondominant hand, and suggestion was manipulated by telling only half the participants the cream could increase the pain of the upcoming cold pressor test. Subsequently, all participants underwent the cold pressor test (8 ± 0.04°C), wherein they submerged the nondominant hand and rated pain intensity on numerical rating scales every 20 seconds up to 2 minutes. In the neutral-affect conditions, there was evidence for the nocebo hyperalgesia effect: participants given the suggestion of pain displayed greater pain than participants not receiving this suggestion, P's < 0.05. Demonstrating a blockage effect, nocebo hyperalgesia did not occur in the positive-affect conditions, P's > 0.5. This is the first study to show that positive affect may disrupt nocebo hyperalgesia thereby pointing to a novel strategy for decreasing nocebo effects without compromising the communication of medical information to patients in clinical settings.

A Positive Mood Induction for Reducing the Formation of Nocebo Effects from Side Effect Information.

BACKGROUND: Providing treatment side effect information can increase the occurrence of side effects through nocebo effects. Nocebo effects from side effect information raise a dilemma for health care, as there is an ethical obligation to disclose potential unpleasant treatment information to patients. PURPOSE: To test the hypothesis that a positive mood induction can block the development of nocebo effects that result from treatment side effect information. METHODS: In a laboratory setting, healthy participants were assigned to one of four conditions in a between-subjects randomized factorial trial. First, participants took part in a mood induction procedure, with half receiving a positive mood induction and the other half a neutral mood induction. Next, participants were told they would experience transcranial direct current stimulation (tDCS). Prior to a sham tDCS task, half of the participants were informed that headache pain is a side effect of tDCS, whereas the other half were not given this information. RESULTS: In the neutral mood condition, the provision of headache side effect information lead to a greater occurrence of headaches, more frequent headaches, and a higher maximum level of headache pain as compared to those given no side effect information. In the positive mood condition, a similar increase in headache pain did not manifest from the provision of side effect information. CONCLUSIONS: This is the first experiment to find that a positive mood induction can block the formation of nocebo effects that arise from side effect information. Inducing positive moods may be an effective strategy for reducing nocebo effects in a variety of clinical settings.

The Application of Persuasion Theory to Placebo Effects.

Placebo effects, or positive outcomes resulting from expectations about a treatment, are powerful components of modern medical care. In this chapter, we suggest that our understanding of placebo effects may benefit from more explicitly connecting this phenomenon to the existing empirical psychological literature on persuasion. Persuasion typically involves an attempt to bring about a change in beliefs or attitudes as a result of providing information on a topic. We begin by providing a brief overview of the psychological literature on placebo effects. We then point to connections between this literature and research on persuasive communication. Although some links have been made, these initial connections have predominantly relied on classic theories of persuasion rather than on more contemporary and comprehensive models. Next, we describe a modern theory of persuasion that may facilitate the study of placebo effects and analyze two issues pertinent to the literature on placebo effects from the lens of this model. Specifically, we consider how and when characteristics of a practitioner (e.g., variables such as perceptions of a practitioner's confidence or competence) can influence the magnitude of placebo effects, and how modern persuasion theory can help in understanding the durability of placebo effects over time. We conclude that examining placebo effects as an outcome of persuasive communication would be a fruitful line of future research.