UCLA LogoResearchers at UCLA have discovered that a gene that is connected to physical pain sensitivity is allied with social sensitivity as well. Their research signifies the disparity in the mu-opioid receptor gene (OPRM1) which is frequently associated with physical pain, is related to how much social pain a person feels in response to social rejection. People with the uncommon gene are more susceptible to rejection. They experience more brain evidence of pain in response to rejection than those who have the common form.

These findings apparently gave weight to the general view that rejection ‘hurts’ by demonstrating that a gene adjusting the body’s most powerful painkillers – mu-opioids is occupied in socially painful experiences too. Research co-author Naomi Eisenberger, UCLA assistant professor of psychology and director of UCLA’s Social and Affective Neuroscience Laboratory is of the opinion that physical pain and social rejection appear to come from the same gene.

In the research, saliva samples from 122 participants were accumulated to examine which form of the OPRM1 gene was present in them. They then calculated sensitivity to rejection in two ways. At first the participants finished a survey that measured their self-reported sensitivity to rejection. The statements like ‘I am very sensitive to any signs that a person might not want to talk to me’ were asked to them and how much they approved or disapproved them.

At UCLA’s Ahmanson–Lovelace Brain Mapping Center, 31 of the 122 participants were observed using functional magnetic resonance imaging (fMRI) during a virtual ball-tossing game where participants were finally socially excluded. They were told that they would be playing this game over the net with two other players who were also part of FMRI scanners. This would be an interactive ball-tossing game. But actually instead of playing with other people they were playing with the current computer program. Primarily, participants were incorporated in the activity but when the two other ‘players’ stopped throwing the ball they were then excluded from the activity.

Eisenberger commented “What we found is that individuals with the rare form of the OPRM1 gene, who were shown in previous work to be more sensitive to physical pain, also reported higher levels of rejection sensitivity and showed greater activity in social pain–related regions of the brain — the dorsal anterior cingulate cortex and anterior insula — in response to being excluded.”

The two brain regions that are repeatedly associated with the distress of physical pain are the dorsal anterior cingulate cortex and anterior insula.

Eisenberger remarked “Although it has long been suggested that mu-opioids play a role in social pain — and there are convincing animal models that show this — this is the first human study to link this mu-opioid receptor gene with social sensitivity in response to rejection.”

Baldwin Way, a UCLA postdoctoral scholar and the lead researcher on the paper mentioned “These findings suggest that the feeling of being given the cold shoulder by a romantic interest or not being picked for a schoolyard game of basketball may arise from the same circuits that are quieted by morphine.”

Eisenberger commented “Because social connection is so important, feeling literally hurt by not having social connections may be an adaptive way to make sure we keep them. Over the course of evolution, the social attachment system, which ensures social connection, may have actually borrowed some of the mechanisms of the pain system to maintain social connections.”

Eisenberger is of the opinion that this overlap in the neurobiology of physical and social pain is good.

This research was published in the early online edition of Proceedings of the National Academy of Sciences.