Study suggests why sadness and sickness go hand-in-hand

It’s a baffling yet all-too-common occurrence: People who have been dealt an emotional blow or who suffer from chronic high stress often develop physical ailments. The grieving widower who dies shortly after his wife dies. The woman who has a heart attack after losing her job. The teenager whose asthma worsens following her parents’ divorce.

A fascinating new study has mapped possible connections to this mind-body response by focusing on the body’s inflammatory response to injury.

Researchers subjected 124 healthy young adults to social stress; the participants had to give an impromptu speech or perform difficult mental arithmetic in front of a nonresponsive, socially rejecting panel of raters. The subjects’ saliva was collected to analyze markers of inflammation (which consisted of a receptor for tumor necrosis factor-a and interleukin-6). Researchers also had 31 volunteers undergo functional MRI brain scanning while playing a computerized game in which the participants were ultimately excluded by two other supposed players (thus causing the volunteer to feel rejected).

The results showed that social rejection caused increases in the inflammatory markers, meaning the body triggered a response to fight off a threat. Chronic inflammation, however, is linked to the development of numerous disorders including asthma, arthritis, heart disease, depression and some types of cancer. The imaging studies showed greater activity in a part of the brain that has been linked to processing rejection-related distress and sadness. The findings then, suggest a specific neurocognitive pathway that links social stress and depression to inflammation.

The big question, said the authors of the study, from the Cousins Center for Psychoneuroimmunology at UCLA, is why neural sensitivity to social rejection is linked to an inflammatory response. One possibility “is that brain regions involved in processing social rejection-related information are associated with a variety of biological responses to social and physical threat,” the authors wrote.

Now, if someone could only find a way to prevent hurt feelings from doing damage elsewhere in the body.

The study was released Monday in the early edition of the Proceedings of the National Academy of Sciences.

-- Shari Roan

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