Ethical Use of Placebo in Research and Practice


A placebo means a therapy or medical intervention that is used for its nonspecific psychophysiological effects, but is without actual effects on the condition being treated. The placebo effect denotes effects due to the meaning of an intervention. The placebo effect has the potential to augment the efficacy of all active medical treatments and procedures. The placebo effect and placebo constitute a convergence point for the social, psychological and physiological aspects of illness and health. The use of placebo has long been controversial, and the ethics of placebos have been debated frequently in history. In recent years, accumulating ethical concern has arisen from the common use of placebo in randomised controlled trials, which may render its participants without early and optimal treatment. This review presents an overview of placebo‐associated ethical questions and offers considerations that are of relevance to medical and research practise.

Key Concepts:

  • A placebo means a therapy or medical intervention that is used for its nonspecific psychophysiological effects, but is without actual effects on the condition being treated.

  • The placebo effect is genuine psychobiological events attributed to the overall therapeutic context.

  • Ethics is a branch of philosophy that involves systematising, defending and recommending concepts of right and wrong conduct.

  • A randomized controlled trial is a study in which people are allocated at random to receive one of several clinical interventions.

  • Evidence‐based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.

Keywords: placebo; placebo effect; ethics; randomised controlled trial; evidence‐based medicine

Figure 1.

Many mechanisms might contribute to placebo effects, including learning, expectations, motivation, conditioning, reward, memory and anxiety reduction, etc.



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Zhang, Hongliang(Jan 2013) Ethical Use of Placebo in Research and Practice. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0024152]