A new study finds widespread alterations in the brains of children exhibiting more callous traits, such as a lack of remorse and disregard for other people’s feelings, compared with the brains of less callous children.
The brain differences, which included large- and small-scale structural alterations, support the idea of callous traits as a neurodevelopmental condition.
The findings are published in the journal Biological Psychiatry.
Using imaging techniques to look at the structure of the brain, researchers from Erasmus University Medical Center, Rotterdam, the Netherlands, found reduced overall brain volumes associated with callous traits in children. Childhood callous traits also correlated with differences in how the brain is wired, referred to as connectivity.
“This is the first study to comprehensively examine the relationship between callous traits and brain structure in the general child population, based on data from over 2,000 10-year-old children,” said senior author, Dr. Charlotte Cecil.
The causes for childhood callous traits are still relatively unknown, but these traits are an early risk factor for negative behaviors and health outcomes later in life, like criminality, psychiatric disorders and substance abuse.
In addition, callous traits aren’t something that you either have or don’t have, said Cecil, but rather they “exist as a continuum in the overall population (i.e., like height or weight), so that everyone scores somewhere along this spectrum.”
“How is it that some children are born with an indifference to the suffering of others?” said Dr. John Krystal, Editor of Biological Psychiatry. “This is an important science question about the neural basis for empathy. It is also an important humanistic question as the lack of a capacity for empathy presents a fundamental challenge to living collaboratively within a community.”
“This study highlights important deficits affecting higher brain centers that may contribute to callousness.”
The affected brain centers include those necessary for decision-making, emotion regulation, and behavior control. The research team ruled out other emotional and behavior issues that often co-occur with callousness, ensuring that the alterations are specific to callous traits — an important finding as the team hopes that future studies will look at whether brain structure could be useful as a screening tool for these traits in children.
“In addition, our study was the first to examine neuroanatomical features of callous traits in a sample with an equal distribution of boys and girls, making it possible to test for sex differences,” said first author, Dr. Koen Bolhuis.
The link between brain structure and callous traits was similar for boys and girls, but the association between brain connectivity and callous traits was only observed in girls.
“This could mean that the brain development related to callous traits differs for girls and boys,” said Bolhuis.
Since the researchers assessed each child only once, they were not able to determine cause and effect or if the callous-related alterations would be able to predict how the children eventually turned out, such as if they would become involved in substance use or do poorly in school.
Still, the findings suggest that kids with callous traits do show differences in brain development, which provides a starting point for future research to understand how severe antisocial behavior develops later in life.