Thanks, it's an interesting article.
I might need to re-read it another time but in general I didn't find anything particularly surprising.
It's interesting to discriminate between the natural course of the health problem and the other non-specific effects, but studies targeted at quantifying the placebo-effect have already taken this in consideration.
I've found the comments about placebo in Parkinson's contradictory:
De la Fuente-Fernandez
et al. (2001) used labeled raclopride, a molecule binding to dopamine receptors, to detect dopamine receptors in the brain with PET scan (positron emission tomography). The patients received either an injection of levodopa
[3] or placebo. They found that the placebo produced the same effect on dopamine receptors, triggering substantial release of endogenous dopamine in the brain. They concluded: “Our findings indicate that the placebo effect in Parkinson’s Disease is powerful and is mediated through activation of the damaged nigrostriatal dopamine system.”
But In the next paragraph:
It still remains to be seen whether these imaging findings translate into clinical results. A more recent study (Fregni et al., 2006) has modified the findings of the preceding study. It studied not just the patient’s subjective response, but also objective tests.
How is a PET scan not an objective test?
In general the article seems to be playing a lot with definitions and subtle semantics. Maybe this is important in the medical field in order to establish clear definitions for the observed phenomena but for general understanding I don't find this to be particularly relevant.
If you check Wikipedia's definition, you'll find a similar definition:
The placebo effect consists of several different effects woven together, and the methods of placebo administration may be as important as the administration itself.
Meaning that placebo is an umbrella term that includes the whole healing ritual: the setting, the consultation, the relationship with the healer, the "placebo object" etc...
Given this definition I find it particularly difficult to study the difference between placebo and "doing nothing" (i.e. natural course of the disease), because even the act of participating in a study with no treatment, being examined and having to report subjective parameters could alter the results.