Frontotemporal white-matter microstructural abnormalities in adolescents with conduct disorder: a diffusion tensor imaging study

Background. Children with conduct disorder (CD) are at increased risk of developing antisocial personality disorder (ASPD) and psychopathy in adulthood. The biological basis for this is poorly understood. A preliminary diffusion tensor magnetic resonance imaging (DT-MRI) study of psychopathic antisocial adults reported significant differences from controls in the fractional anisotropy (FA) of the uncinate fasciculus (UF), a white-matter tract that connects the amygdala to the frontal lobe. However, it is unknown whether developmental abnormalities are present in the UF of younger individuals with CD. Method. We used DT-MRI tractography to investigate, for the first time, the microstructural integrity of the UF in adolescents with CD, and age-related differences in this tract. We compared FA and perpendicular diffusivity of the UF in 27 adolescents with CD and 16 healthy controls (12 to 19 years old) who did not differ significantly in age, IQ or substance use history. To confirm that these findings were specific to the UF, the same measurements were extracted from two non-limbic control tracts. Participants in the CD group had a history of serious aggressive and violent behaviour, including robbery, burglary, grievous bodily harm and sexual assault. Results. Individuals with CD had a significantly increased FA (p=0.006), and reduced perpendicular diffusivity (p=0.002), in the left UF. Furthermore, there were significant age-related between-group differences in perpendicular diffusivity of the same tract (Z(obs)=2.40, p=0.01). Controls, but not those with CD, showed significant age-related maturation. There were no significant between-group differences in any measure within the control tracts. Conclusions. Adolescents with CD have significant differences in the 'connectivity' and maturation of UF.