For years, researchers have studied the brains of children and adolescents who display mental health issues to determine if there are any structural differences that could be attributed to their behavior. Children who have what researchers call "callous-unemotional" traits have a less developed conscience and sense of empathy. They show less fear and caution, respond less to negative stimuli, and are more inclined to engage in risky activities. Now, a new study has found structural brain differences that may account for these callous-unemotional traits. But only in boys.

For the study, a team of researchers from the University of Basel and University of Basel Psychiatric Hospital used magnetic resonance imaging to get a closer look at the brains of a random assortment of 189 typical children and teens. Researchers were particularly looking at the brains of kids who displayed callous-unemotional traits to determine if there were any structural differences that could account for their behavior and if so, to see if these differences were the same for boys as they were for girls.

The study revealed structural differences in the brains of children with callous-unemotional traits, but only in boys. Researchers found that boys who displayed higher levels of callous-unemotional traits had a larger anterior insula, the region of the brain associated with empathy and recognizing emotions in others. Girls with callous-unemotional traits did not have a larger anterior insula nor did they have any other structural brain differences from their female peers who didn't display these traits.

Nora Maria Raschle, a researcher at the Psychiatric Hospital of the University of Basel in Switzerland and a lead author of the study, noted that her team's next phase of research would be to figure out why some children with callous-unemotional traits develop more serious and persistent mental health disorders later in life while others do not.

The study was published in the journal Neuroscience: Clinical.