Alterations in Region-Specific Gray Matter Volume Underlying Callous Unemotional Traits in Adolescents

Background: Callous-unemotional (CU) traits during adolescence, for example, shallow affect or lack of remorse, have been shown to be a risk marker for antisocial behavior. Only a few studies have investigated structural brain alterations underlying CU traits, and findings are inconclusive. The study examines CU symptomatology and gray matter volume (GMV) associations.

Methods: Structural brain MRI data were collected from a sample of 578 adolescents (60% male) with a mean age of 14.85 years (SD = 2.30; range = 10-19 years). CU traits were indexed via the Inventory for Callous Unemotional Traits (ICU). Region-wise volumetric parameters were obtained following parcellation of the brain into 68 cortical and 14 subcortical regions per participant. A multiple linear regression was conducted using age, sex, IQ, intracranial volume, and handedness as covariates to assess the relationship between ICU scores and GMV.

Results: Our regression analysis showed significance (R² = 0.244, F[87,490] = 1.821, p < 0.001). Specifically, GMV of the left parahippocampal gyrus, left pars orbitalis, right medial orbitofrontal cortex, right superior temporal, and right putamen had significant negative regression loadings, indicating those with lower GMV in these regions had higher ICU scores. The right postcentral gyrus and right hippocampus had significant positive regression loadings, indicating those with higher GMV in these regions had higher ICU scores.

Conclusions: Utilizing a transdiagnostic sample of adolescents, our study found significant associations between CU traits and GMV. Understanding the neurobiological associations of CU traits could be crucial for early intervention and targeted treatments, particularly for those at risk of antisocial behavior.