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Callous-unemotional traits relate to differences in brain structure of boys

Analysis of neuroimages showed that callous-unemotional traits are associated with the variations in brain structure of boys only, highlighting the importance of considering sex as a factor in child psychiatry.

“While all evidence points towards the importance of considering sex as a variable within research designs, the majority of neuroimaging studies, particularly those on [callous-unemotional] traits, focus solely on males,” Nora Marie Raschle, PhD, from the department of child and adolescent psychiatry at Psychiatric University Hospital and University of Basel in Switzerland, and colleagues wrote. “This may be due to higher levels of crimes, delinquency, or aggressive and antisocial behavior being reported in boys, but nevertheless limits the generalizability of the findings.”

Most previous research into the relationship between callous-unemotional traits and brain structure has focused on studying populations with a psychiatric diagnosis, especially conduct disorder, according to the researchers In this study, Raschle and colleagues examined the brain development of 189 teenaged, typically-developing boys and girls to determine the relationship between callous-unemotional traits and brain structure using voxel-based morphometry. They conducted whole-brain multiple regression analyses with controls in the whole sample and in boys and girls individually.

The investigators found that larger volume of the bilateral anterior insula in typically developing boys (P < .05) was related to higher levels of callous-unemotional traits; however, this difference in brain structure was not seen in girls with the same personality traits. Specifically, analysis showed that sex and callous-unemotional traits interacted to predict insula gray matter volume, which explained 19% of the variance in callous-unemotional traits for boys, according to Raschle and colleagues. Analysis showed no significant positive or negative correlations between callous-unemotional traits and gray matter volume in the bilateral anterior insula within girls.

"Our findings demonstrate that callous-unemotional traits are related to differences in brain structure in typically-developing boys without a clinical diagnosis," Raschle said in a press release. "In a next step, we want to find out what kind of trigger leads some of these children to develop mental health problems later in life while others never develop problems." – by Savannah Demko

Disclosures: Raschle reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.