Common brain changes found in children with autism, ADHD and OCD
A team of Toronto scientists has found similarities in brain impairments in children with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD) and obsessive compulsive disorder (OCD). The study involved brain imaging of white matter in 200 children with autism, ADHD, OCD or no diagnosis.
White matter is made up of bundles of nerve fibers that connect cell bodies across the brain, and enable communication between different brain regions. (If you are interested, you can read about the differences between grey and white matter here.)
“We found impairments in white matter is the main tract connecting the right and left hemispheres of the brain in children with either autism, ADHD or OCD, when compared to healthy children in the control group,” says Dr. Stephanie Ameis, first author on the study.
This particular white matter tract, the corpus callosum, is the largest in the brain and among the first to develop.
The research team also found children with autism and ADHD showed more severe impairments affecting more of the brain’s white matter than those with OCD. This finding may reflect the fact that both autism and ADHD typically have an onset at a much younger age than OCD, and at a time when a number of different white matter tracts are going through rapid development.
Autism, ADHD and OCD have common symptoms and are linked by some of the same genes. Yet historically they have been studied as separate disorders. Together, these three neurodevelopmental disorders affect roughly 15 per cent of children and youth.
The study is part of a major Ontario initiative, the Province of Ontario Neurodevelopmental Disorders Network (POND) that is examining various childhood brain-related disorders collectively, to better understand their similarities and differences, and develop more effective and targeted therapies.
Many of the behaviours that contribute to impairment in autism, ADHD, and OCD, such as attention problems or social difficulties, occur across these conditions, and differ in severity from person to person. The researchers found that the brain’s white matter structure was associated with a spectrum of behavioral symptoms present across these diagnoses.
“Children with greater brain impairment also had higher impairments in functioning in daily life, regardless of their diagnosis,” said Dr. Ameis.
This finding has implications for our understanding of the nature of brain-related disorders. By providing biological evidence that brain structure relates to a spectrum of behavioural symptoms that cut across different developmental conditions, it highlights the shared biology among such conditions.
And it points to the potential that treatments targeting a spectrum of behaviours may be relevant for all three conditions.
Ameis, S., Lerch, J., Taylor, M., Lee, W., Viviano, J., Pipitone, J., Nazeri, A., Croarkin, P., Voineskos, A., Lai, M., Crosbie, J., Brian, J., Soreni, N., Schachar, R., Szatmari, P., Arnold, P., & Anagnostou, E. (2016). A Diffusion Tensor Imaging Study in Children With ADHD, Autism Spectrum Disorder, OCD, and Matched Controls: Distinct and Non-Distinct White Matter Disruption and Dimensional Brain-Behavior Relationships American Journal of Psychiatry DOI: 10.1176/appi.ajp.2016.15111435