It is amazing how many people remain resistant to the idea that Attention Deficit Hyperactivity Disorder (ADHD) is a genuine problem. It is likely becoming more common as we live in a progressively more demanding world in which our inner resources can easily become overwhelmed. It is a “real” problem since if it is severe it can cause suffering and second, ADHD can also be associated with a range of other difficulties. There is also more and more evidence that it is associated with robust disturbances in the structure and functioning of the brain.
There is an important study published in Human Brain Mapping that reveals an association between ADHD and a decrease in cortical volume, surface area and folding throughout the brain. Researchers from the Kennedy Krieger Institute in Baltimore, Maryland, found that children with ADHD has decreased total brain volume and decreased volume throughout the cerebral cortex. What is new is that the reduction in cortical volume seems to be the result of decreased folding in the cortex. This in turn suggests that folding – a process that starts around the 14th-16th weeks of pregnancy and continues into infancy - is the key structural brain feature associated with ADHD.
The investigators examined 21 children with ADHD aged 8-12 years, and a control group of 35 unaffected children matched for age and gender. The children with ADHD had more than 7 percent reduction in total cerebral volume compared with the control group.
One of the design problems in human beings is that the brain is encased in a hard skull that moves little. So once the brain has grown to fill the skull, the only way to increase the surface area of the brain is for the cortex to become more folded. The whole process of cortical folding is crucial to increasing the structural and functional capacity of the brain.
This is of great interest, particularly in light of the study just published in the Proceedings of the National Academies of Sciences that indicates that the brain of people with ADHD can catch up later. That study did not look at brain folding, so it will be interesting to see exactly how the brain can catch up, and how we might be able to give it a helping hand.