Scientific tools, fake treatments, or triggers for psychological healing: How clinical trial participants conceptualise placebos

Felicity L. Bishop, Eric E. Jacobson, Jessica R. Shaw, Ted J. Kaptchuk

Placebos are an essential tool in randomised clinical trials, where they are used to control for bias and contextual healing effects. Placebos and their effects are also studied from multiple diverse perspectives, but the perspectives of placebo recipients are seldom considered. Research shows that people form cognitive and affective representations of active treatments such as medicines, and that they use these representations to guide their behaviour; it seems reasonable to suggest that people might also think about and develop representations of placebos. We adopted a qualitative approach to examine in detail how participants in one RCT, conducted in the USA, conceptualised placebos. 12 people were interviewed 3 times each, at the start, middle, and end of a trial of placebo effects and acupuncture for Irritable Bowel Syndrome (IBS). The interview data were analysed inductively and we identified four ways in which the participants conceptualised placebos: placebos are necessary for research; placebo effects are fake; placebo acupuncture is not real acupuncture; placebos have real effects mediated by psychological mechanisms. Participants' conceptualisations of placebos were dynamic and situated in a broader psychological and socio-cultural context. Seeing placebo effects as legitimate seemed to be facilitated by having more holistic models of healing, viewing IBS as psychological, and seeing treatment as multifactorial. However, some participants maintained a negative view of placebo effects (e.g. as illusions) that was apparently inconsistent with their other beliefs (e.g. in mind-body healing mechanisms). This may indicate a dominance of negative discourses around placebos at a socio-cultural level. Negative views of placebos are inconsistent with evidence that placebo treatments can have positive effects on symptoms. RCT participants should be informed about potential benefits of placebo treatments to avoid misunderstandings and unease. Future work should improve methods of providing participants with full accurate information about placebos and their effects.