Nocebo effects, i.e., adverse treatment effects which are induced by patients’ expectations, are known to contribute to the experience of physical symptoms such as pain and itch. A better understanding of how to minimize nocebo responses might eventually contribute to enhanced treatment effects. However, little is known about how to reduce nocebo effects. In the current randomized controlled study, we tested whether nocebo effects can be minimized by positive expectation induction with respect to electrical and histaminic itch stimuli. First, negative expectations about electrical itch stimuli were induced by verbal suggestion and conditioning (part 1: induction of nocebo effect). Second, participants were randomized to either the experimental group or one of the control groups (part 2: reversing nocebo effect). In the experimental group, positive expectations were induced by conditioning with verbal suggestion. In the control groups either the negative expectation induction was continued or an extinction procedure was applied. Afterwards, a histamine application test was conducted. Positive expectation induction resulted in a significantly smaller nocebo effect in comparison with both control groups. Mean change itch NRS scores showed that the nocebo effect was even reversed, indicating a placebo effect. Comparable effects were also found for histamine application. This study is the first to demonstrate that nocebo effects can be minimized and even reversed by conditioning with verbal suggestion. The results of the current study indicate that learning via counterconditioning and verbal suggestion represents a promising strategy for diminishing nocebo responses.

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Background: Research into mental disorders has found mental imagery to be a maintaining factor for psychological distress. However, studies investigating mental imagery in eating disorders are scarce. Aim: The aim of the present study was to compare spontaneous mental imagery related to eating, weight and/or appearance and intrusive prospective imagery in women with an eating disorder with female healthy controls. Methods: Spontaneous mental imagery and intrusive prospective imagery were assessed in adult women with an eating disorder (n = 29) and in female healthy controls (n = 32) using a semi-structured interview and the Impact of Future Events Scale, respectively. Results: In comparison with healthy controls, the spontaneous mental images in individuals with an eating disorder involved more sensory modalities (U = 156.50, p < .001, r = –.51), were more vivid (t (52) = 2.04, p = .047, d = .55), negative (U = 103.00, p < .001, r = –.62), and anxiety provoking (U = 158.50, p < .001, r = –.49), and were experienced with a lower sense of control (U = 215.00, p = .009, r = –.36). The emotional impact of intrusive prospective imagery (U = 105.00, p < .001, r = –.66) was also higher in individuals with an eating disorder, as was the number of negative prospective images (U = 283.00, p = .016, r = –.31). Conclusions: Our findings are consistent with previous research on mental imagery in other psychiatric disorders, and provide possibilities for incorporating imagery-based techniques in treatment interventions.

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