Related Experiment Video
Updated: May 27, 2026
06:45
Rating L-DOPA-Induced Dyskinesias in the Unilaterally 6-OHDA-Lesioned Rat Model of Parkinson's Disease
Published on: October 4, 2021
Placebo Effect in Levodopa-Induced Dyskinesia: A Systematic Review and Meta-Analysis
Luiz Vinicius Silva Correa1,2, Alexandre Martins do Nascimento3, Bruno Lopes Santos-Lobato4
1Department of Neuroscience, University of São Paulo, Ribeirão Preto, Brazil.
Movement Disorders Clinical Practice
|May 25, 2026
Summary
The placebo effect in Parkinson's disease (PD) treatment for levodopa-induced dyskinesia (LID) is significant and clinically relevant. Factors like older age and shorter study duration influence this placebo response in LID trials.
Area of Science:
- Neurology
- Clinical Trials
- Pharmacology
Background:
- Levodopa-induced dyskinesia (LID) is a common complication in Parkinson's disease (PD) treatment.
- The magnitude of the placebo effect specifically in LID clinical trials is not well-established.
Purpose of the Study:
- To quantify the placebo response in LID clinical trials.
- To identify factors that may moderate the placebo effect in LID.
Main Methods:
- Systematic review and meta-analysis of double-blind, placebo-controlled trials.
- Inclusion of 31 publications with 1329 patients diagnosed with PD and LID.
- Primary outcome: change in dyskinesia severity in the placebo arm, analyzed using random-effects models.
Main Results:
- A statistically significant placebo response of moderate magnitude was observed (SMD = -0.48, p < 0.0001).
- This corresponded to clinically meaningful improvements, such as reduced UDysRS scores and increased "Good On Time."
- Older patient age, higher proportion of female participants, and shorter study duration were associated with a larger placebo effect.
Conclusions:
- The placebo response in LID is a consistent and clinically relevant phenomenon.
- Patient demographics and trial duration are significant moderators of the placebo effect.
- Quantifying the placebo response is crucial for designing and interpreting future LID trials.
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