"Conclusions:

It is evident that placebo effects are real and that they have therapeutic potential. Laboratory evidence supports the existence of numerous placebo mechanisms and effects in both healthy volunteers and patients with a variety of medical conditions. Furthermore, clinically relevant evidence demonstrates that placebo effects can have meaningful therapeutic effects, by virtue of magnitude and duration, in different patient populations. Although substantial progress has been made in understanding placebo effects, considerable scientific work remains to be done in both laboratory experiments and translational clinical trial research, with the ultimate aim of harnessing placebo effects to improve patient care. "

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2832199/

I had better respond to this reply, which I see is NOT responsive to the references I supplied in my original post. The link shown here, to a paper co-authored by Ted J Kaptchuk, was surely submitted here in good faith, and I thank the user who submitted it for that, but in fact Mr. Kaptchuk (he is NOT a doctor and does not have good training in human physiology or research methods) is well known as a promoter of ideas about healing through thinking that have no factual basis and are not backed up by science. Basically all roads to strong statements about "placebo effect" lead back to writings by Ted J Kaptchuk, which are heavily promoted by press releases.

So I invite all readers of Hacker News to compare the references I supply in this thread to the references supplied for the proposition that there are clinically meaningful placebo effects that actually heal disease in human patients. I especially encourage everyone reading this thread to review all the cited studies with the checklist by Peter Norvig, Google's director of research, "Warning Signs in Experimental Design and Interpretation"

http://norvig.com/experiment-design.html

in mind as you read the studies. Statistically valid, carefully designed research studies do NOT show clinically useful placebo effects. Preliminary studies by researchers who promote "alternative medicine" occasionally show patient self-reports of benefits in subjective symptoms (pain or discomfort) from placebo. Those have not been replicated by independent researchers.

Careful studies do not show healing of disease from administering placebos or by other mind-over-matter processes. Extraordinary claims require extraordinary evidence, and the burden of proof is on people (people without medical training and clinical experience, let me remind you) who claim that anyone can cure serious disease with a mere placebo effect.

The reply above prompted me to rewrite my original comment here (the comment that is "grandfather" to this comment) as a FAQ file. I'll post that below.

Because the submitted article mentions the placebo effect, in the usual manner of popular articles, perhaps I should share here some links that are helpful for understanding what placebo effects are all about. Some of these online links cite quite a few useful scholarly publications.

http://www.sciencebasedmedicine.org/index.php/michael-specte...

"In other words, the best research we have strongly suggests that placebo effects are illusions, not real physiological effects. The possible exception to this are the subjective symptoms of pain and nausea, where the placebo effects are highly variable and may be due to subjective reporting."

Despite the numerous press releases on the Web pointing to publications co-authored by Ted Kaptchuk, who has NO medical training or credentials,

http://www.sciencebasedmedicine.org/index.php/dummy-medicine...

http://www.sciencebasedmedicine.org/index.php/dummy-medicine...

the statements typically found in those articles, such as "Recent research demonstrates that placebo effects are genuine psychobiological phenomenon [sic] attributable to the overall therapeutic context, and that placebo effects can be robust in both laboratory and clinical settings" are untrue.

http://theness.com/neurologicablog/index.php/the-rise-and-fa...

"Despite the spin of the authors – these results put placebo medicine into crystal clear perspective, and I think they are generalizable and consistent with other placebo studies. For objective physiological outcomes, there is no significant placebo effect. Placebos are no better than no treatment at all."

http://www.ncbi.nlm.nih.gov/pubmed/20091554

"We did not find that placebo interventions have important clinical effects in general. However, in certain settings placebo interventions can influence patient-reported outcomes, especially pain and nausea, though it is difficult to distinguish patient-reported effects of placebo from biased reporting. The effect on pain varied, even among trials with low risk of bias, from negligible to clinically important. Variations in the effect of placebo were partly explained by variations in how trials were conducted and how patients were informed."

Fabrizio Benedetti, a co-author of one of the most cited papers who is also a medical doctor, sums up his view this way: "I am a doctor, it is true, but I am mainly a neurophysiologist, so I use the placebo response as a model to understand how our brain works. I am not sure that in the future it will have a clinical application."

http://www.brainsciencepodcast.com/storage/transcripts/year-...

To sum up, despite claims to the contrary by a person without medical training who is often covered by the lay press, the best-considered view among medical practitioners with clinical experience is that the placebo response has no clinical application.

See also:

http://www.sciencebasedmedicine.org/index.php/does-thinking-...

http://www.skepdic.com/placebo.html

http://www.sciencebasedmedicine.org/index.php/revisiting-dan...