Delays in Brain Development May Cause ADHD

A study has found that crucial parts of the brain develop at a slower rate in children with ADHD.

During childhood, the brain’s cortex thickens from the back of the brain to the front, and eventually thins again during adolescence. However, researchers who studied brain-imaging scans from 446 children (half of whom had ADHD) found a three-year delay, on average, in the cortical development of those with the disorder. The motor cortex, however, which carries out orders for planned movements, matured faster in children with ADHD.

“Finding a normal pattern of cortex maturation, albeit delayed, in children with ADHD should be reassuring to families,” explained lead researcher Philip Shaw, M.D., of the National Institute of Mental Health Child Psychiatry Branch. “And this could explain why many children with ADHD seem to grow out of the disorder.” Researchers will continue to follow these children to determine if cortical development in children with ADHD catches up to normal brain development during adolescence.

While these results show the power of brain scans in searching for the cause of ADHD, researchers emphasize that a clinical assessment based on symptoms and patient history is required for an accurate diagnosis. “Brain imaging is not ready for use as a diagnostic tool in ADHD,” concludes Shaw.

To read more about this and other studies visit Proceedings of the National Academy of Sciences