ADHD and Genetic Research
Research over the past decade has been relatively inconclusive regarding the etiology of ADHD and its genetic links. The January 07, 2009 special issue of American Journal of Medical Genetics (AJMG): Part B: Neuropsychiatric Genetics presents a comprehensive overview of the latest genetic research of ADHD. In search of the ADHD holy grail, researchers have attempted to identify specific genes that underlie the disorder in the hopes that gene discovery will lead to better treatments for the disorder.
The studies cited in the AJMG indicate that one genetic marker may be associated with ADHD symptoms with the possibility that many genes are involved in ADHD. Each of these genes may play small roles in their overall presentation of ADHD symptoms. The currents studies then are inconclusive and suggest the need for larger studies a) to determine if there are genetic mechanisms underlying ADHD, b) to determine what these mechanisms do if they exist, and c) to determine whether these initial findings can be confirmed.
An important issue needs to be raised here: If one can find a genetic marker and the various genes involved in ADHD, is it therefore a disease like diabetes, cancer, or atherosclerosis? Or is it a genetic trait like red hair, crooked teeth, or freckles? Personally, it seems to me to be more of a trait than anything else. Even the noted ADHD expert, Dr. Ed Hallowell and his colleague, Dr. Peter Jensen, have indicated they perceive ADHD as a trait.
The second issue that needs to be raised here is: What is it that the researchers can do with the genetic information they are seeking? The answer to this question is medication. Most of the genetic studies have leaned toward a genomic search for genes that may someday be used to predict which children respond most favorably to the stimulant medications. The current studies indicate that, although there are likely to be genetic factors that are associated with stimulant efficacy in children with ADHD, there are no single genes with a very large impact on treatment response. This may be because ADHD is a conflation of diffused attention, poor organization, hyperactivity, etc. Are there genetic markers for each of these individual characteristics?
This presents us with the problem of antecedence (chicken or the egg). It appears that ADHD is a conflation of a variety of characteristics. This is precisely how it is diagnosed. These characteristics could be acquired in one of two methods: They could be genetic (heritable) or they could be learned. One can learn to be disorganized, hyperactive, or even have diffused attention. Most of us experience this now in our busy, noisy existence on this planet. Does this change our genetic makeup?
We know that when we learn something, certain genes are switched on which activate messenger RNA to build neural networks supporting long-term memory. Therefore, we are substantially changing our genetic makeup. The brain is incredibly malleable or labile. This is both significant and promising. We can and do shape it through our various daily activities. It would hold then, that we can change our diffused attention into focused attention, our disorganization into organization, and our hyperactivity into calm behavior. However, if we obdurately argue that ADHD is a disorder or disability, then hope for this change is diminished if not extinguished. Now is the time to realize that there is hope for persons with attention challenges; change is quite possible and achievable. Genetic research points us in this direction. It’s past time to follow
