For centuries physicians have known that some patients improve when given fake medicine, like pills that contain no real drugs. But how can docs predict which of their cases are most likely to benefit from the placebo effect? 

 

To find out, researchers ran 50 volunteers through a battery of personality test. Then they injected a bit of salt water into the subjects' muscles, and told them they'd be getting a little something to relieve the resulting pain, although that little something was actually a sham.

 

The researchers found that pretend meds don't do much for people who tend toward hostility. They work best for folks who are naturally resilient and altruistic. The subjects who responded to the foul treatment actually produced more of the body's own natural painkillers. That's good news for the stoic and one more thing for the angry to be mad about.