It is only natural that parents who are told that their child has been diagnosed as having Attention Deficit Hyperactivity Disorder (ADHD) will want to know exactly what went wrong. Unfortunately, this is something to which they are not going to get a simple answer. Researchers are still uncertain about the underlying factors that cause ADHD.
Recent research indicates that ADHD is not a disorder of attention per se as researchers had assumed. It is linked to a developmental failure in the brain circuitry that underlies inhibition and self-control. This loss of self-control in turn impairs other important brain functions crucial for maintaining attention, including the ability to defer immediate rewards for later, greater gain.
Studies conducted by the National Institute of Mental Health in U.S.A. found that the right prefrontal cortex, two basal ganglia and the vermis region of the cerebellum are significantly smaller than normal in children with ADHD. These findings make sense because the brain areas that are reduced in size in children with ADHD are the very ones that regulate attention.
Genetics also plays a role in ADHD. According to research findings, ADHD has a heritability approaching 80 percent. In other words, this means that up to 80 percent of the differences in attention, hyperactivity and impulsivity between people with ADHD and those without the disorder can be explained by genetic factors.
Nongenetic factors that have been associated with ADHD include premature birth, maternal alcohol and tobacco use, exposure to high levels of lead in early childhood and brain injuries, especially those that involve the prefrontal cortex. But even together, these factors can account for only between 20 and 30 percent of ADHD cases among boys; among girls, they account for an even smaller percentage.
Some misconceptions about ADHD
At one point, people believed that a poor home environment might be the cause of ADHD. However, the latest research findings increasingly point to biological causes for the disorder. Not all children from unstable or dysfunctional homes have ADHD. And not all children with ADHD come from dysfunctional families. Parents can heave a sigh of relief that this is something that is not their fault.
Another pet theory was that refined sugar and food additives make children hyperactive and inattentive. As a result, parents were encouraged to stop serving children foods containing artificial flavorings, preservatives, and sugars. However, data from a later study lead scientists to conclude that the restricted diet only seemed to help about 5 percent of children with ADHD, mostly either young children or children with food allergies.
In addition, ADHD cannot be linked to too much TV or food allergies or poor schools.