Sex differences of uncinate fasciculus structural connectivity in individuals with conduct disorder

Conduct disorder (CD) is one of the most common behavior disorders in adolescents, such as impulsivity, aggression, and running from school. Males are more likely to develop CD than females, and two previous diffusion tensor imaging (DTI) studies have demonstrated abnormal microstructural integrity in the uncinate fasciculus (UF) in boys with CD compared to a healthy control group. However, little is known about changes in the UF in females with CD. In this study, the UF was illustrated by tractography; then, the fractional anisotropy (FA), axial diffusivity, mean diffusion, radial diffusivity (RD), and the length and number of the UF fiber bundles were compared between male and female patients with CD and between female patients with CD and female healthy controls, as well as between males with CD and healthy males. We found that males with CD showed significantly higher FA of the bilateral UF and significantly lower RD of the left UF when comparing with females with CD. Meanwhile, significantly higher FA and lower RD of the bilateral UF were also found in boys with CD relative to the male healthy controls. Our results replicated previous reports that the microstructural integrity of the UF was abnormal in boys with CD. Additionally, our results demonstrated significant gender effects on the UF of patients with CD, which may indicate why boys have higher rates of conduct problems than girls.