People in the study who score high on a personality trait called resilience, the ability to adjust to environmental change, had the highest amount of natural painkiller activation, according to findings by University of Michigan. (Agencies)
Researchers 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.
Researchers have shown that when a person feels physical pain, their brains release chemicals called opioids into the space between neurons, dampening pain signals.
"This is the first study to peer into the human brain to show that the opioid system is activated during social rejection," said David T Hsu, lead author of the study.
The study involved 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 setup 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 were not interested in them.
Brain scans made during these moments showed opioid release, measured by looking at the availability of mu-opioid receptors on brain cells.
The effect was largest in the brain regions called the ventral striatum, amygdala, mid-line thalamus, and periaqueductal gray - areas that are also known to be involved in physical pain.
"Individuals who scored high for the resiliency trait on a personality questionnaire tended to be capable of more opioid release during social rejection, especially in the amygdala," Hsu said.
"This suggests that opioid release in this structure during social rejection may be protective or adaptive," Hsu said.
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.
Hsu noted that perhaps new opioid medications without addictive potential may be an effective treatment for depression and social anxiety.
The study was published in the journal Molecular Psychiatry.
People in the study who score high on a personality trait called resilience, the ability to adjust to environmental change, had the highest amount of natural painkiller activation, according to findings by University of Michigan.