Do placebos have a measureable impact on healing gastric ulcers?
On TED.com Ben Goldacre makes the claim:
We know for example that two sugar pills a day are a more effective treatment for getting rid of gastric ulcers than one sugar pill a day. Two sugar pills a day beats one pill a day. And that's an outrageous and ridiculous finding, but it's true.
But do we really know that placebos have healing effects on gastric ulcers? On his blog Nick Barrowman makes the case that we don't.
I don't want to preempt a reply from Ben Goldacre but this is the reference from his discussion of placebos on his bad science blog (blog discussion here, academic reference here).
Unfortunately for us mortals the academic reference is behind an expensive paywall. But other trials of placebos are accessible (at least to me). One from the BMJ in 2008 which sought to test the components of the placebo effect in irritable bowel syndrome concluded (my emphasis):
Factors contributing to the placebo effect can be progressively combined in a manner resembling a graded dose escalation of component parts. Non-specific effects can produce statistically and clinically significant outcomes and the patient-practitioner relationship is the most robust component.
An earlier paper by the same team in the BMJ in 2006 found that some placebos were better than others in treating pain:
The sham device had greater effects than the placebo pill on self reported pain and severity of symptoms over the entire course of treatment...
So I'm aware I'm not quite answering the claim about ulcers (unless the detail is in the paywalled paper) but I think the general idea that placebos can have significant effects is clear and also the idea that some placebos are better than others.
EDIT The Nick Barrowman blog uses a different reference to the one I assumed Goldacre was referring to. The reference shows an effect but Barrowman criticises the study for not doing a proper randomised trial between two different placebos. Fair comment, but while specifically correct for ulcers and placebos, proper trials on alternative placebos have been done and still show effects (see my examples).
