Regional grey matter volume and concentration in at-risk adolescents: Untangling associations with callous-unemotional traits and conduct disorder symptoms

• Grey matter concentration (GMC) and volume (GMV) were studied in antisocial youths.
• Conduct disorder (CD) symptoms are related to higher amygdala GMC.
• Callous-unemotional (CU) traits are related to lower amygdala and insula GMC.
• Both measures interact in the prediction of insula GMV.
• Results suggest partly dissociable mechanisms for CD symptoms and CU traits.

Structural Magnetic Resonance Imaging studies have reported volume reductions in several brain regions implicated in social cognition and emotion recognition in juvenile antisocial populations. However, it is unclear whether these structural abnormalities are specifically related to antisocial features, or to co-occurring callous-unemotional (CU) traits. The present study employed voxel-based morphometry to assess both grey matter volume (GMV) and grey matter concentration (GMC) in a large representative at-risk sample of adolescents (n=134; mean age 17.7 yr), characterized by a broad range of CU trait and conduct disorder (CD) symptom scores. There was a significant interaction between CD symptom and CU trait scores in the prediction of GMV in the anterior insula, with a significant positive association between CU traits and GMV in youth low on CD symptoms only. In addition, we found a significant unique positive association between CD symptoms and GMC in the amygdala, and unique negative associations between CU traits and GMC in the amygdala and insula. These findings are in line with accumulating evidence of distinct associations of CD symptoms and CU traits with amygdala and insula GMC in juvenile antisocial populations.