The nature and power of the placebo effect

J Clin Epidemiol. 2006 Apr;59(4):331-5. doi: 10.1016/j.jclinepi.2005.12.001.


Progress in understanding the placebo effect and its clinical significance depends on conceptual clarification of this elusive phenomenon and critical appraisal of research bearing on the influence of placebo interventions on clinical outcomes. Here we locate the placebo effect within a typology of modes of healing, distinguish between the observed placebo response in randomized controlled trials and the placebo effect, and examine critically a recent meta-analysis of clinical trials that challenges the reality of the placebo effect.

Publication types

  • Review

MeSH terms

  • Analgesia
  • Double-Blind Method
  • Humans
  • Placebo Effect*
  • Placebos / therapeutic use
  • Randomized Controlled Trials as Topic


  • Placebos