Rude and mean behaviour not only upsets people, it can also increase their risk of getting arthritis, says a new study.
Psychologist George Slavich of the University of California, Los Angeles, and colleagues said that social rejection could trigger diseases linked to inflammation.
124 volunteers were asked to give speeches and perform mental arithmetic in front of a panel of dismissive observers.
Functional MRI scans showed this triggered increased activity in two brain regions associated with rejection.
Understanding the role the brain plays in conditions linked to inflammation - such as asthma, arthritis, cardiovascular disease and depression - will help in the development of new treatments to combat them, says Slavich.
The study has been published in Proceedings of the National Academy of Sciences.