Placebo Effect and Placebo Concept - a Critical Methodological and Conceptual Analysis of Reports on the Magnitude of the Placebo Effect.

Author(s): Kiene, H.

Abstract: Since the publication of H.K. Beecher's classic work on placebos, 'lbe Powerful Placebo' (1955), it has been generally accepied that 35% of patients with any of a wide variety of disorders can be satisfactorily treated with placebos alone. Most recently, average eure rates of 70% and up to 100% have been quoted. Just like pharmacological preparations, placebos are credited with possessing time-effect curves, cumulation and carry-over effects, differentiated actions depending on colour, size or packing, and even toxic effects. lt has been postulated that placebos can prolong life, that placebo effects occur in surgery as well as in medicine, and that they are mediated by endorphins.T'he present article analyses the source material that forms the scientific basis for these and other claims. Analysis shows - as already demonstrated in an earlier study (G.S. Kienle, Der sogenannte Placeboeffekt, Stuttgart 1995) - that the studies on which such ideas are based, except perhaps in bronchial asthma, do not in any way justify the conclusions drawn from them. The truth is that the placebo effect is counterfeited by a variety of factors including the natural history of the disease, regression to the mean, concomitant treatments, obliging reports, experimental subordination, severe methodological defects in the studies, misquotation, etc.; even, on occasion, by the fact that the supposed placebo is actually not a placebo, but has to be acknowledged as having a specific action on the condition for which it is being given. A further reason tot mi@judgement is the lack of clarity of the placebo concept itsel£ Experimental subordination and the conditioning are other areas of insufficient conceptual differentiation.In summary, it is fair to say that the widely published data in the literature relating to the magnitude and frequency of the placebo effect are unfounded and grossly overrated, if not indeed totally false. The authors conclude by posing the question of whether the existence of the so-called placebo effect is itself not largely - er indeed totally - illusory.

Keyword(s): Placeboeffekt

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