Attention Deficit Hyperactivity Disorder (ADHD), also called Attention Deficit Disorder (ADD), is a disorder that affects 3-5% of children in the U.S. Characteristics of the affected children include constant motion, the inability to keep their minds on one thing, and acting before they think. Other symptoms include trouble with friends, school, and family. In the past, treatment has involved mostly the administration of drugs such as Ritalin, Devedrine, Cylert, or Adderal. However, ADHD is typically diagnosed by observing a child's behavior, and many believe that this is not an accurate test, since some children could just have a naturally lower attention span. So before scientists are able to correctly diagnose ADHD, they need to understand whether it is "nature," meaning ADHD is mostly caused by genetics and/or brain abnormalities, or "nurture," meaning the disorder is mostly caused by poor parenting or a dysfunctional home environment. .
Those supporting "nature" argue that brain size is about 5% smaller in affected children. The two areas controlling attention, the frontal cortex and the basal ganglia, are significantly smaller and are less active during attention tests. Symptoms are also thought to be caused by imbalances in neurotransmitters (chemicals that transmit nerve signals) which mean some parts of the brain are overactive, while other parts are underactive. ADHD seems to also run in families, supporting the fact that ADHD may be genetically based. Some scientists think that what combination of genes you have determines what version of ADHD you have. This has been the most commonly accepted cause, so that is why medication is so often used. The drugs work by changing levels of neurotransmitters, and are proven to slow symptoms in about 90% of children with ADHD. Other theories include head injuries, brain damage due to infection, and consumption of food additives, including refined sugar.
