[disgruntledphd2]

This is quite an old paper, and I actually wrote a blog post about it (back when I had a blog). However, my issue with this study is that there was no deceptive placebo condition (i.e. what normally happens). I actually attempted to replicate this finding and didn't find any effect when a deceptive condition was involved, suggesting that IBS may be a special case.

Interestingly enough, IBS patients have been found to have non-opioid mediated relief of pain, which is atypical (normally naloxone blocks these effects) so there may be something weird going on with this condition in more general terms.

Also, its worth noting that in modern conceptions of placebo, its part of every treatment. If you have ever felt the effects of a cup of coffee before approximately 30 minutes, that's probably a placebo. Ditto for headache tablets that work immediately, before the active substance could have gotten into the bloodstream.

Also, with respect to the drinking of water, that's unlikely to be an explanation as that quantity of water is typically not enough to provide relief from IBS.

[NatW]

>with respect to the drinking of water, that's unlikely...

With my reading, taking water - in gulps to wash down the pill - at particular times/regularity could be a/the significant factor getting measured in this study. Perhaps there is a threshold effect in taking the water (e.g: it helps people on the threshold of dehydration), or perhaps it's the time of day taken. I may be wrong, but I don't think it should just be summarily dismissed yet.

[sizzle]

I have definitely experienced the coffee and pain killer placebo more often than not.

Thinking about it now, it make sense that once you ingest either to alleviate certain symptoms, you let go of a portion of directed anxiety/overt attention in expectation of relief thereafter.

Despite knowing the placebo pill beforehand, I'd hazard a guess that the same brain areas associated with non-placebo oral administration will light up with activity in an MRI scan.

Anyone know if there is any scientific literature on this phenomenon?

[disgruntledphd2]

For the placebo effects of coffee - Kirsch & Wiexel 1988 (can't find it online, annoyingly enough).

There probably are some fMRI studies, but I really don't trust most of those due to the difficulties in avoiding multiple comparisions (see Vul et al 2009, Voodoo Neuroscience).