Placebo Analgesia

I put this here because of the nocebo comment. Make sure your doctor doesn't use it on you.
http://bodyinmind.org/placebo-analgesia/
One paragraph here:
According to findings from neuroimaging studies, we create a nocebo response (the opposite of placebo, i.e. the expectation of increased pain leading to increased pain) faster than we do a placebo response.  I wonder why this is.