Is the placebo powerless? Update of a systematic review with 52 new randomized trials comparing placebo with no treatment

  title={Is the placebo powerless? Update of a systematic review with 52 new randomized trials comparing placebo with no treatment},
  author={Asbj{\o}rn Hr{\~o}bjartsson and Peter Christian G{\o}tzsche},
  journal={Journal of Internal Medicine},
Background.  It is widely believed that placebo interventions induce powerful effects. We could not confirm this in a systematic review of 114 randomized trials that compared placebo‐treated with untreated patients. 
Effects of placebos without deception compared with no treatment: A systematic review and meta‐analysis
To investigate the clinical efficacy of open‐label placebos compared with no treatment in a systematic review and meta‐analysis, a large number of patients were randomly assigned to receive either placebos or no treatment.
Identifying Placebo Effects with Data from Clinical Trials
  • A. Malani
  • Psychology, Medicine
    Journal of Political Economy
  • 2006
Evidence of placebo effects in trials of antiulcer and cholesterol‐lowering drugs is found and a simple test for placebo effects is proposed.
Influence of placebo effect in mental disorders research: A systematic review and meta-analysis.
A small placebo effect was observed in mental disorders research overall, and in patients with anxiety or depression, and these findings should be interpreted with caution in the light of heterogeneity and risk of bias.
Randomized Placebo-Controlled Placebo Trial to Determine the Placebo Effect Size.
The present study indicated that true placebo effect sizes can be analyzed through a proper IPRCT design, and instead of treating high numbers of patients with placebos in a RCT, which increases the risk for subjects not receiving the active treatment, the I PRCT technique seems to be much more appropriate to analyze the effect sizes of any active treatment.
Dynamic nature of the placebo response.
This editorial will highlight key information supporting a contemporary view of placebo, and recent research has helped to redefine placebo.
The placebo effect revisited: lessons learned to date.
  • I. Kirsch
  • Psychology
    Complementary therapies in medicine
  • 2013
Placebo: no longer a phantom response
It is proposed that mechanisms similar to those that cause a placebo response may underlie the beneficial effects of religious belief and other neural stimuli.
Placebo effect characteristics observed in a single, international, longitudinal study in Huntington's disease
The aim was to analyze the placebo effect in Huntington's disease and to propose a new design for clinical trials based on the placebo‐control design.
Understanding the placebo effect. Part 1: placebo use in clinical trials.
  • R. Howland
  • Psychology, Medicine
    Journal of psychosocial nursing and mental health services
  • 2008
This article discusses some important aspects of the placebo effect on the basis of clinical research studies in pharmacology, and describes important findings about the psychological and neurobiological processes that underlie the placebos.
Effects of placebos without deception compared with no treatment: protocol for a systematic review and meta-analysis
A protocol for the first systematic review and meta-analysis of studies of the effects of non-deceptive placebos compared with no treatment and the methods of delivery used for non- deceptively delivered placebos is presented.


Concept of true and perceived placebo effects
A review of the literature shows that most authors confuse the perceived placebo effect with thetrue placebo effect, and a distinction between the perceived and the true placebo effects would be helpful in understanding the complex phenomena involved in a placebo response.
What are the main methodological problems in the estimation of placebo effects?
The powerful placebo effect: fact or fiction?
The Use of Placebo Interventions in Medical Practice—A National Questionnaire Survey of Danish Clinicians
The authors sent a questionnaire to 772 randomly selected Danish clinicians and asked them about their use of placebo interventions, finding that the most important reason for the use of Placebo interventions was to avoid a confrontation with the patient.
The placebo effect: can we use it better?
  • V. Oh
  • Psychology, Medicine
  • 1994
The net effect of a given drug is the sum of the drug's pharmacological effects and the placebo effect associated with the act of treatment, and the use of placebos raises important ethical questions.
Meta-analysis in clinical trials.
A randomized controlled trial of fentanyl for abortion pain.
Fentanyl, when compared with the placebo, reduced abortion pain by 1.0 point on an 11-point scale, which was of questionable clinical significance and was less than desired by the women included in the study.
Sensitivity of effect variables in rheumatoid arthritis: a meta-analysis of 130 placebo controlled NSAID trials.
In a meta-analysis of placebo controlled NSAID trials, the sensitivity of the effect variables was calculated as the correlation coefficient and as the difference between drug and placebo, divided by