To the Editor The phenomenon that Paul et al1 describe in their study of acute cough, where active interventions and placebo showed no difference yet were both superior to the no treatment group,1 may be an example of what has been described previously as placebo by proxy.2 The idea that family members and physicians may have an emotional response to a patient’s treatment and perceived improvement on subjective complaints2 and that a patient’s response to therapy may be affected by the behavior of other people who know the patient is undergoing therapy3 seem to be especially prominent in pediatric conditions.2 This phenomenon is similar to the common occurrence in placebo-controlled randomized trials of animals (eg, lameness from osteoarthritis in dogs4 and headshaking in horses5), where owners and physicians detect significant improvements in both active and placebo interventions but objective measures show no change.
Kossowsky J, Kaptchuk TJ. Placebo Effects in Infants, Toddlers, and Parents. JAMA Pediatr. 2015;169(5):505. doi:10.1001/jamapediatrics.2014.3798