A study suggests that being rejected in social situations can do more than cause hurt feelings; it may actually increase inflammation and make you sick.

Researchers at the University of California at Los Angeles have found that rejection increases the same inflammatory proteins that drive conditions like rheumatoid arthritis, asthma, depression, cardiovascular disease and some types of cancer.

“Usually you see increases in inflammatory activity due to physical injury. If you have a cut in the arm you see increases in inflammatory activity and that’s very adaptive because that response can help fight off pathogens and reduce the likelihood of infection,” says study author George M. Slavich, PhD, a postdoctoral fellow at the UCLA Cousins Center for Psychoneuroimmunology. “It’s interesting that you can get increases in inflammatory activity by exposure to social stressors.”

The study, published online in the Proceedings of the National Academy of Sciences involved 124 healthy participants who were put through two potentially stressful social situations: First, the volunteers were brought into a lab and given five minutes to prepare a speech and five minutes to deliver it. Then they were asked to count backwards from 2,935 by increments of seven or 13.  

During the public speaking tasks, two researchers dressed “officially” in lab coats expressed frustration and disapproval at participants’ speed and ability.

Before and after the public speaking tests, oral swabs were taken to measure levels of inflammation while they were exposed to these social stressors. Researchers looked for increases in two inflammatory markers – tumor necrosis factor alpha, or TNF-alpha, and interleukin-6.

During the second part of the study, participants were given MRI brain scans while they played a computerized game of catch.

Though they were actually playing against the computer, they were led to believe that they were playing against other people.

Halfway through the game, the computer dropped the participant from the game of catch in an attempt to create a feeling of social rejection.

Researchers then studied the brain scans to assess neural activity during those moments of social rejection.

What scientists found was that the participants who were dropped from the game had more activity in brain areas related to stress and rejection. They also experienced larger increases in their inflammatory markers.

“Biological components of stress have direct implications for a number of major disorders,” says Slavich. “The way you think about the world can have very serious implications for your personal health and well-being.”

Researchers say they believe this is the first study to show which neurocognitive pathways may be involved in the body’s inflammatory responses to strong social stress. 

They also say their findings raise the question of why neural sensitivity to social rejection is linked to inflammation.  

It may be that social rejection involves a component of pain, for example, or because social and physical threats are often connected, rejection may be causing the body to anticipate a physical injury by increasing proteins that drive inflammation.

Slavich says this increased inflammatory activity isn’t likely to be a big deal if it only happens occasionally. But if it is chronic or frequent, that could be more serious.  

“If it happens a lot, you may have that reaction many times during the day or week and that’s when it becomes problematic because many of these major disorders have inflammation as a core component of the disorder,” Slavich explains.

Slavich says it can also be a problem if you are having these psychological and biological responses in the absence of a real threat.

“Nothing has happened yet, it’s just that you are predicting the worse can happen. But all the while you are having a biological response as if you are in the presence of danger, when all you are doing is imagining it,” Slavich explains.

He says the take away message for patients is – if your thoughts are getting the better of you, it could have a direct and negative effect on your body.

“When people were told they had to give the speech and do the math test, many showed increases in inflammatory activity and experienced that as distressing. But at the same time you could experience that as a challenging set of circumstances and a chance to show your strengths and virtues,” Slavich explains. “A lot of the time we live in our own realities and those realities are constructed by our minds.”

“I would say don’t treat your thoughts as facts. Treat your thoughts as hypotheses or guesses and collect information on whether or not the thoughts you have were or are accurate or not,” Slavich continues. “When those thoughts are accurate, then that’s useful information for you. But at the same time, when you are having thoughts that aren’t accurate, use that information to revise your beliefs.”