A Link Between Brain Size and Hyperactivity in Children and Teens
In a recent study published in the 09 October 2002 Journal of the American Medical Association, hyperactive children and teens were found to have a slightly smaller brain size than their counterparts without the hyperactivity disorder. The American Academy of Pediatrics estimates that hyperactivity affects between four to twelve percent of school-age children, making it one of the most common childhood psychiatric disorders. Symptoms of attention-deficit-hyperactivity disorder (ADHD) include short attention span, impulsive behavior, difficulty in the ability to focus and a tendency to fidget.
The researchers found that ADHD was associated with approximately a three to four percent decrease in volume throughout the brain. There was also a correlation between brain size and the severity of the symptoms. The study also indicated that the brains of ADHD children seem to develop at a normal pace. For some reason, however, the brain volume does not catch up to the brain volume of other children who do not have the disorder.
This finding suggests that ADHD is a product of biology rather than poor parenting. It was also noted that smaller brain size does not necessary signify less intelligence. Although the cause of this difference in brain size remains unclear, it does not seem to be related to the use of common ADHD drugs, such as Ritalin. This part of the study is important because it indicates that ADHD can be treated with these pharmacological means without harming the children’s brains.
References
Castellanos, F. X., Lee, P. P., Sharp, W., Jeffries, N. O., Greenstein, D. K., Clasen, L. S., Blumenthal, J. D., James, R. S., Ebens, C. L., Walter, J. M., Zijdenbos, A., Evans, A. C., Giedd, J. N., & Rapoport, J. L. (2002). Developmental trajectories of brain volume abnormalities in children and adolescents with attention-deficit/hyperactivity disorder. Journal of the American Medical Association, 288, (14), 1740-1748.