[Chris Noble]

Originally Posted by David Bailey

It would rather seem that the Hrobjartsson and Gotzsche paper is at one extreme of a spectrum.

Their 2001 NEJM paper Is the Placebo Powerless?- An Analysis of Clinical Trials Comparing Placebo with No Treatment has been cited 405 times. This includes updates including more trials. At least in clinical trials that have both placebo and no-treatment groups the placebo effect is small to non-existent. There are some studies that have provided strong evidence that under certain conditions a real placebo effect can be produced. I gave you the reference fro one fMRI study which is probably the best example of this kind. I did this to give you an idea of the spectrum of results. Certainly you can read all 405 articles if you want.

Here it is put into some context:

placebo effect

Here is a quote from that article:

"Doctors in one study successfully eliminated warts by painting them with a brightly colored, inert dye and promising patients the warts would be gone when the color wore off. In a study of asthmatics, researchers found that they could produce dilation of the airways by simply telling people they were inhaling a bronchiodilator, even when they weren't. Patients suffering pain after wisdom-tooth extraction got just as much relief from a fake application of ultrasound as from a real one, so long as both patient and therapist thought the machine was on. Fifty-two percent of the colitis patients treated with placebo in 11 different trials reported feeling better -- and 50 percent of the inflamed intestines actually looked better when assessed with a sigmoidoscope"

Did any of these directly compare a placebo group with a matched non-treatment group?

Of course, there is a problem in that people often recover anyway, and it is hard to compare a placebo treatment with a pretend treatment, but even so, I don't think the range of placebo treatments is as limited as Chris suggested.

Note that the Hrobjartsson and Gotzsche paper is a meta analysis of other papers in which they eliminated some research as being in their view flawed.

David

As I stated above this paper has been cited 405 times and has been updated. Other researchers have checked the meta-analysis and have found it to be sound.