Placebo Effect

I've wondered before (although perhaps not on this weblog, can't remember) how much of all medicine rests on the placebo effect. How many treatments would simply stop working if the placebo effect were suddenly erased from our minds? Consider this, from the article 13 Things That Do Not Make Sense:

Don't try this at home. Several times a day, for several days, you induce pain in someone. You control the pain with morphine until the final day of the experiment, when you replace the morphine with saline solution. Guess what? The saline takes the pain away.

This is the placebo effect: somehow, sometimes, a whole lot of nothing can be very powerful. Except it's not quite nothing. When Fabrizio Benedetti of the University of Turin in Italy carried out the above experiment, he added a final twist by adding naloxone, a drug that blocks the effects of morphine, to the saline. The shocking result? The pain-relieving power of saline solution disappeared.

Stop reading now if you don't want me to ruin certain treatments for you, because faith is everything...

Still here? Okay... I was discussing this with my neuromuscular therapist friend yesterday, and she mentioned a few interesting studies, one which showed that of the "alternative" pain management techniques, acupuncture appeared to be the most effective. However, another study showed that fake acupuncture (sticking in needles randomly?) is pretty much just as effective as real acupuncture. Did some Googling, found a bunch of references, but I particularly liked this one: Sham Acupuncture More Effective Than Sugar Pill in Easing Arm Pain.

First question that leaps to mind: what do you use as a control group if you're studying the placebo effect? :-)