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—We thank Drs Ernst and Resch for reemphasizing an important point: to distinguish a placebo response from the natural history of a condition, a clinical trial must include an untreated group as well as a placebo group. We made this point in the "Implications for Research Design" section of our article.The factors Dr Cleophas refers to as biases may well contribute to apparent patient improvement observed in clinical trials. As noted in our article, these include patient expectations of being helped and characteristics of the treatment situation that influence patients to report improvement. These factors can influence apparent patient improvement with an active treatment as well as with a placebo. Rather than viewing these as biases and trying to eliminate them in clinical trials, it may be more fruitful to identify and assess these processes and target them for systematic study.
Turner JA, Deyo RA, Loeser JD, Fordyce WE, Von Korff M. The Importance of Placebo Effects-Reply. JAMA. 1995;273(4):284. doi:10.1001/jama.1995.03520280027022