Can psychological factors predict placebo responding in adults with anxiety and negative mood?
LE3 .A278 2017
Bachelor of Science
Placebo responding is a common and well-known problem in clinical trials. This project focused on the relationship between four psychological factors (i.e., expectations, somatic focus, catastrophizing, and optimism/pessimism) and the placebo response. These factors were measured within the context of a larger study investigating the impact of probiotics on adults experiencing anxiety and negative mood. Participants filled out questionnaires before and after treatment assessing their symptoms of anxiety and negative mood. They also completed a pre-treatment placebo response questionnaire. Regression analyses revealed that none of the four factors was predictive of improvements in the placebo condition. However, among participants in the probiotic condition, the ACES and ANCEQ predicted improvements on four outcome measures, suggesting that participants’ expectations and catastrophizing interacted with the probiotics in improving participants’ scores on these specific outcome measures.
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