Placebo effect characteristics observed in a single, international, longitudinal study in Huntington's disease†‡§
Funding agencies: Junta de Castilla y León grant, 2008.
Relevant conflicts of interest/financial disclosures: Nothing to report. Full financial disclosures and author roles may be found in the online version of this article.
Members of the European Huntington's Disease Initiative Study Group are listed in the Appendix.
Abstract
Background:
Classically, clinical trials are based on the placebo-control design. Our aim was to analyze the placebo effect in Huntington's disease.
Methods:
Placebo data were obtained from an international, longitudinal, placebo-controlled trial for Huntington's disease (European Huntington's Disease Initiative Study Group). One-hundred and eighty patients were evaluated using the Unified Huntington Disease Rating Scale over 36 months. A placebo effect was defined as an improvement of at least 50% over baseline scores in the Unified Huntington Disease Rating Scale, and clinically relevant when at least 10% of the population met it.
Results:
Only behavior showed a significant placebo effect, and the proportion of the patients with placebo effect ranged from 16% (first visit) to 41% (last visit). Nondepressed patients with better functional status were most likely to be placebo-responders over time.
Conclusions:
In Huntington's disease, behavior seems to be more vulnerable to placebo than overall motor function, cognition, and function © 2011 Movement Disorder Society
