Microstructural abnormalities in the white matter of the brain may play a role in the pathophysiology of ADHD in children and adolescents, a recent Chinese study suggests.
In this study, children and adolescents with untreated ADHD and no comorbidities (n=33; age 7–16 years) were assessed by psychiatric interview and compared with healthy controls (n=35; age 7–14 years). Behavioural problems* and executive functions† were evaluated, and diffusion tensor imaging (fractional anisotropy, including mean, axial and radial diffusivities) was used to probe microstructural abnormalities in the white matter.
The authors found that fractional anisotropy was increased in the left posterior cingulum bundle (an important component of the limbic system involved in emotions and cognitive function) in children/adolescents with ADHD versus controls. Furthermore, the averaged fractional anisotropy in this cluster showed a significant negative correlation with study problems*; and interestingly, a significant positive correlation with cognitive flexibility‡ (p<0.02 for all). Similar findings were observed in subanalyses of boys only, and of children younger than 12 years.
These findings suggest that white matter abnormalities within the limbic network could play a role in the pathophysiology of ADHD in children and adolescents and support the independence of sex and maturation effects.
*Assessed using the Conners’ Parent Rating Scale
†Assessed using the Stroop Colour-Word Test and the Wisconsin Card Sorting test
‡Assessed using the Wisconsin Card Sorting test only
Chen L, Huang X, Lei D, et al. Microstructural abnormalities of the brain white matter in attention-deficit/hyperactivity disorder. J Psychiatry Neurosci 2015; 40: 280-287.