October 11, 2013
The Social Side Of The Brain’s Release Of Pain-killing Opioids
Brett Smith for redOrbit.com - Your Universe Online
While previous research has shown that our brains release pain-killing opioids when the body experiences physical harm, a new study in the journal Molecular Psychiatry has revealed that this system is also activated by social pain.
The study researchers also discovered that those who score high on a personality attribute called resilience, or the capacity to cope with environmental change, showed the highest level of natural painkiller activation.
"This is the first study to peer into the human brain to show that the opioid system is activated during social rejection," said study author David T. Hsu, an assistant professor of psychiatry at the University of Michigan. "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."
In the study, 18 adult participants were asked to look at pictures and fabricated personal profiles of hundreds of other adults. In an attempt to simulate an online dating environment, each volunteer selected some profiles they might be most interested in romantically.
Next, the participants were told to lay down in a brain imaging machine called a PET scanner, where they were eventually told that the individuals they has chosen were not interested in them.
Brain scans taken during these moments of rejection showed opioid release in the participants’ brains. The phenomenon was the most prevalent in the brain regions that are known to be involved in physical pain.
While the participants were told ahead of time that the "dating" profiles were not real, the simulated rejection was enough to stimulate an emotional and opioid response.
According to Hsu, the personality of each participant appeared to play a role in the individual response of their own opioid system.
"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," the emotion-processing region of the brain, Hsu said. "This suggests that opioid release in this structure during social rejection may be protective or adaptive."
The more opioid release seen in a brain area called the pregenual cingulate cortex, the less the volunteers reported being upset by the news of rejection, the researchers noted.
The scientists also looked at what happens when the volunteers were told that one of the ‘people’ behind a profile they had selected had also reciprocated interest in them. During this type of social acceptance, some brain regions showed more opioid release.
"The opioid system is known to play a role in both reducing pain and promoting pleasure, and our study shows that it also does this in the social environment," Hsu explained.
The study researchers noted that their findings could be significant for people who suffer from depression or social anxiety who may have an irregular opioid response to the types of social situations examined in the study.
"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,” Hsu said. “Similarly, these individuals may also have less opioid release during positive social interactions, and therefore may not gain as much from social support.”
He added that the knowledge of chemical mechanisms behind social interactions could help some people understand their responses to certain social situations.