Placebo effect of medication cost in Parkinson disease: a randomized double-blind study

Neurology. 2015 Feb 24;84(8):794-802. doi: 10.1212/WNL.0000000000001282. Epub 2015 Jan 28.


Objective: To examine the effect of cost, a traditionally "inactive" trait of intervention, as contributor to the response to therapeutic interventions.

Methods: We conducted a prospective double-blind study in 12 patients with moderate to severe Parkinson disease and motor fluctuations (mean age 62.4 ± 7.9 years; mean disease duration 11 ± 6 years) who were randomized to a "cheap" or "expensive" subcutaneous "novel injectable dopamine agonist" placebo (normal saline). Patients were crossed over to the alternate arm approximately 4 hours later. Blinded motor assessments in the "practically defined off" state, before and after each intervention, included the Unified Parkinson's Disease Rating Scale motor subscale, the Purdue Pegboard Test, and a tapping task. Measurements of brain activity were performed using a feedback-based visual-motor associative learning functional MRI task. Order effect was examined using stratified analysis.

Results: Although both placebos improved motor function, benefit was greater when patients were randomized first to expensive placebo, with a magnitude halfway between that of cheap placebo and levodopa. Brain activation was greater upon first-given cheap but not upon first-given expensive placebo or by levodopa. Regardless of order of administration, only cheap placebo increased activation in the left lateral sensorimotor cortex and other regions.

Conclusion: Expensive placebo significantly improved motor function and decreased brain activation in a direction and magnitude comparable to, albeit less than, levodopa. Perceptions of cost are capable of altering the placebo response in clinical studies.

Classification of evidence: This study provides Class III evidence that perception of cost is capable of influencing motor function and brain activation in Parkinson disease.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antiparkinson Agents / administration & dosage*
  • Antiparkinson Agents / economics*
  • Cost of Illness
  • Cross-Over Studies
  • Dopamine Agonists / administration & dosage
  • Dopamine Agonists / economics
  • Double-Blind Method
  • Female
  • Humans
  • Injections, Subcutaneous
  • Levodopa / administration & dosage
  • Levodopa / economics
  • Male
  • Middle Aged
  • Parkinson Disease / drug therapy*
  • Parkinson Disease / economics*
  • Parkinson Disease / psychology
  • Placebo Effect*
  • Prospective Studies
  • Treatment Outcome


  • Antiparkinson Agents
  • Dopamine Agonists
  • Levodopa