The team found the body’s opioid system can act to ease emotional pain as well as physical pain, suggesting that the hurt we feel when snubbed isn’t “all in our heads” as it provokes a chemical reaction.
The findings could pave the way for the development of new medications to treat depression and other social anxiety traits.
The study by a University of Michigan Medical School team showed that people who score high on a personality trait called resilience – the ability to adjust to environmental change – had the highest amount of natural painkiller activation.
The team combined advanced brain scanning that can track chemical release in the brain with a model of social rejection based on online dating.
They focused on the mu-opioid receptor system in the brain – the same system that the team has studied for years in relation to response to physical pain.
Assistant professor of psychiatry Dr David Hsu said the new research on social rejection grew out of recent studies which suggested that the brain pathways activated during physical pain and social pain are similar.
He said: “This is the first study to peer into the human brain to show that the opioid system is activated during social rejection.
“In general, opioids have been known to be released during social distress and isolation in animals, but where this occurs in the human brain has not been shown until now.”
The study, published in the journal Molecular Psychiatry, examined 18 adults who were asked to view photos and fictitious personal profiles of hundreds of other adults.
Each selected some who they might be most interested in romantically – a set up similar to online dating.
But then, when the participants were lying in a brain imaging machine called a PET scanner, they were informed that the individuals they found attractive and interesting had rejected them.
Brain scans made during these moments showed opioid release, measured by looking at the availability of mu-opioid receptors on brain cells.
The more opioid release during social rejection in another brain area called the pregenual cingulate cortex, the less the participants reported being put in a bad mood by the news that they’d been snubbed.
Dr Hsu hopes to expand his study to look at how those who are vulnerable to or currently suffering from depression or social anxiety have an abnormal opioid response to social rejection and acceptance.
He said: “It is possible that those with depression or social anxiety are less capable of releasing opioids during times of social distress, and therefore do not recover as quickly or fully from a negative social experience.”