Which are the placebo effects - comment on Kaptchuk et al’s IBS placebo study
“A placebo can only be assumed to be inert according to current knowledge” . The sham procedure used in Kaptchuk et al’s IBS placebo study  is already known not to be inert. One cannot touch the body without biological effects. Some of these effects may in theory be attributable to placebo, others are normal reactions to touch and can have many dimensions to them [3, 4]. Therefore the sham acupuncture which necessarily involves touch and pressure is not an inert placebo (something admitted by its proponents ) and cannot have effects solely attributable to the ritual of therapy  as the authors claim . Thus placebo effects in both the sham treatment arms are necessarily overstated. Additionally some aspects of the effects of touch are probably specific to the acupuncture therapy , a possibility acknowledged by the lead author in recent discussions about the role of touch in taiji chuan [9, 10].
In these articles about taiji chuan the lead author also demonstrates knowledge of complex interventions and the difficulties of doing research on them. Among other things, the evidence he cites comes from acupuncture related studies showing how many aspects of patient-practitioner psycho- social-verbal interactions are specific aspects of acupuncture treatment . This and other supporting studies have demonstrated the complex nature of acupuncture as an intervention [8, 12]. Unfortunately in the third arm of the IBS placebo study since sham acupuncture was used to investigate placebo effects, not only is there a problem with the sham not being inert, but the study will have attributed to placebo some effects due to these non-placebo related specific components of acupuncture intervention. There is no discussion of this and no attempt to tease apart placebo related treatment components from these acupuncture specific non- placebo related patient-practitioner interactional components . Thus the study will necessarily have further overestimated placebo effects in this third arm, due to this mislabeling of treatment components.
This placebo study chose to use sham acupuncture as its ‘placebo’ treatment. This was an unfortunate choice. No sham acupuncture treatment has ever been demonstrated to be inert, raising questions about bias in acupuncture studies  and thus the suitability of sham acupuncture in trials of acupuncture . Recently experts have raised the issue of whether there should be a moratorium on sham acupuncture studies due in part to these difficulties . The authors of this study have chosen to ignore the same evidence and arguments about complex interventions and the inherent difficulty of separating their placebo effects that they have used and cited elsewhere [8, 9, 10], raising other questions about this placebo study.
It would have been much more interesting and relevant to answer the questions about placebo that this study attempted to investigate if they had chosen a sham (placebo) standard pharmaceutical intervention administered in normal GP practice where the doctor usually does not have time to talk much with the patient, and use as a third arm an extended discussion treatment arm added to the placebo medication.
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Stephen Birch Foundation (Stichting) for the Study of Traditional East Asian Medicine (STEAM), Amsterdam, the Netherlands
Mark Bovey Coordinator, Acupuncture Research Resource Centre, Thames Valley University, London, UK
Competing interests: None declared
Competing interests: No competing interests