When patients with Parkinson's disease received an injection described as an effective drug costing $1,500 per dose, their motor function improved significantly more than when they got one supposedly costing $100, scientists reported on Wednesday.
Underlining the power of expectations, the motor improvements, measured by a standard Parkinson's assessment, occurred even though both injections contained only saline and no active ingredients.
The research, said an editorial in the journal Neurology, which published it, "takes the study of placebo effect to a new dimension."