Evidence for placebo effects on physical but not on biochemical outcome parameters: a review of clinical trials
2007

Placebo Effects on Physical vs. Biochemical Outcomes

Sample size: 34 publication 10 minutes Evidence: moderate

Author Information

Author(s): Meissner Karin, Distel Hans, Mitzdorf Ulla

Primary Institution: Institute of Medical Psychology, Ludwig-Maximilians-University Munich

Hypothesis

Do placebo treatments have different effects on physical and biochemical outcome parameters?

Conclusion

Placebo interventions can improve physical disease processes more effectively than biochemical processes.

Supporting Evidence

  • 50% of trials measuring physical parameters showed significant placebo effects.
  • Only 6% of trials measuring biochemical parameters showed significant placebo effects.
  • The meta-analysis revealed a significant overall improvement of parameters during placebo treatment.

Takeaway

When people think they are getting treatment, their bodies can sometimes feel better, especially for physical problems, but not so much for chemical ones.

Methodology

The study analyzed data from placebo-controlled clinical trials to assess the effects of placebo on physical and biochemical parameters.

Potential Biases

Potential biases include the natural course of disease affecting outcomes and the risk of regression to the mean.

Limitations

The study's classification of parameters was based on different trials, which may introduce confounding variables.

Participant Demographics

The trials included various clinical conditions but did not specify participant demographics.

Statistical Information

P-Value

p<0.0001

Confidence Interval

95% CI 0.22 to 0.46

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1186/1741-7015-5-3

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