LOS ANGELES, Dec. 4 (UPI) -- A person's genes may determine the intensity of people's responses to social rejection, U.S. researchers suggest.
A study reviewed by Faculty of 1000 Biology member Markus Heilig shows small differences in the gene for the opioid receptor -- opium-like painkillers that relieve not only physical pain, but also some forms of emotional stress -- can determine the intensity of people's responses to social rejection.
Researchers at the University of California-Los Angeles questioned people about their responses to social rejection -- considered a form of emotional stress. They also performed brain scans on people playing a video game in which they were excluded from tossing a ball with computer-generated players.
The study, published in the Proceedings of the National Academy of Sciences, shows people with a certain mutation in their opioid receptor reacted more strongly to social rejection than those with a normal opioid receptor.
"Strengthening the conclusions from this study is the fact that a similar polymorphism -- genetic difference -- has independently arisen in the rhesus macaque," Heilig said.
The same portion of the brain that is responsible for the response to physical pain became activated as a result of social rejection, suggesting that, to the brain, emotions really cause "hurt," Heilig said.
