

Placebo Effects Revisited - tokenadult
http://www.sciencebasedmedicine.org/?p=4304

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timcederman
As far as I'm aware, a physiological response to a placebo (and corresponding
nocebo) was a well-documented effect. Some examples:

* Heart-rate (not sure what else?) being equally affected by decaf and regular coffee

* Impaired cognitive effects from drinking far too soon after initial drinking (and as measured by BAC)

* Reduced stress hormones when arm is placed in an ice bucket after taking a placebo and being told it's morphine

* Physical nausea including vomiting after being told potential side effects of a trial "drug"

In terms of the body "healing" itself, I can see how the placebo effect could
be attributed to other things.

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tokenadult
_a well-documented effect_

I just did some of the obvious Google Scholar searches on some of the issues
you mention, but I'm not seeing clear statements of these findings being well
documented in a publication that is not behind a paywall for me. Do you have
citations at hand?

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timcederman
Try pubmed directly rather than Google Scholar. Most examples I'm quoting are
articles I've read in New Scientist so if you have a subscription you can
check their article history. I promise I'm not making them up.

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pmichaud
tl;dr: Some people named Hróbjartsson and Gøtzsche did a meta analysis on
clinical trials suggesting that the placebo effect is solely a reflection of
bias or rigor in the given experiment, not of some physiological, "mind over
matter" phenomenon.

~~~
tokenadult
More particularly, from the submitted article, "There is no measurable
physiological benefit from placebo interventions for any objective outcome.
There is a measured benefit for some subjective outcomes (mostly pain, nausea,
asthma, and phobias), but the wide variation in effect size suggests this is
due to trial design (and therefore bias) rather than a real effect." In my
words, it might be expected that one would see a placebo effect if the
clinical records are based on patient self-reports of, e.g., pain or nasal
congestion, but a placebo effect would be quite astounding if they were
statistically significant over multiple double-blind trials in detection of a
chemical in a blood test.

~~~
_delirium
Do patterns of brain activation not count as an "objective" difference to
them? The effects of many placebos are clearly visible on MRI.

~~~
tokenadult
What are some examples in peer-reviewed literature for which you have
citations at hand?

~~~
_delirium
This is a recent one from _Science_ that got a good amount of press when it
came out: <http://www.sciencemag.org/cgi/content/abstract/326/5951/404>

~~~
tokenadult
Thank you for that reference. That led me by hyperlink to this

<http://brain.oxfordjournals.org/cgi/content/full/awq019v1>

and the link here draws a distinction that I think is important, the
distinction between injury and pain. The paradox of pain, as this article
says, is that patients with severe injury have little pain, while other
patients with possibly no injury at all have severe pain. Granting that sham
treatments (placebos) can reduce patient perception of pain, how do we
establish that they produce more healing of injury, more consistently, than
the passage of time as the body's evolutionarily selected healing mechanisms
work?

