Last year I mentioned an interesting study showing how placebos can release endorphins. MSN have an interesting article about the physical changes that placebos seem to bring about. In particular there's a study come out showing that the people that got the most benefit from antidepressants were ones who showed a particular pattern of brain activity when they were earlier given placebos. This confirms that the benefits of placebos are not merely "imaginary", and also suggests a means of screening patients to see if they're likely to benefit from antidepressants.
In another study, researchers enabled patients to learn how to control their chronic pain through thought alone.

An interesting study indicates that we make snap judgments about people based simply on looking at their face for a mere 100 milliseconds. These judgments changed a little if the time was increased to 1/2 second, but any more time than that simply increased certainty that the judgment was accurate.