11/19/2012 05:52 pm ET Updated Jan 19, 2013

Placebos Don't Work On Hostile People, But Do Work On Altruistic People: Study

Aches and pains getting you down? Or maybe they really tick you off. If that's the case, maybe don't look to a placebo to give you any relief. Because a new study shows that sugar pills are less effective for people who are quick to anger. The work appears in the journal Neuropsychopharmacology. [Marta Peciᅢᄆa et al., Personality Trait Predictors of Placebo Analgesia and Neurobiological Correlates]

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 tests. They then injected a bit of saltwater 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 faux 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.