The nights in the burn department were always difficult, and many of the patients would regularly ask (beg) for more painkillers to help them fall sleep. One afternoon I overheard the doctors tell the nurses not to give a certain patient any more morphine. A few hours later, when the same patient started begging for painkillers I saw the nurse go to her room with an injection and a few seconds later the patient quietly went to sleep. When the nurse stopped by my room, I asked her about it and with a smile she told me that she had given the patient IV fluid.This was the first time I experienced (secondhand) the power of placebo. I am not sure if they ever treated me with the same method, but it is certainly possible.Years later I became even more impressed with placebos when I learned that a placebo for pain has a very clear physiology. When we expect to get pain relief, our brain secretes a substance that is very much like morphine and this substance makes the pain go away. This means that even if the injection contains no painkiller we can still get pain relief courtesy of our own brain.Yesterday we published a study in The Journal of the American Medical Association about placebos. In this study we showed that when people get more expensive painkillers (placebos in our case) they expect a lot and get a lot of pain relief, but when the price of these pills is discounted, the expectations are lowered and so is their efficacy. As it turns out, with painkillers, we sometimes get what we pay for.For a story in the NYT see this link