"Is ADHD genetic?" As a doctor who treats Attention Deficit Hyperactivity Disoder, I am frequently asked this question by concerned parents and caregivers.
As the mother of a son with ADHD, I too am very interested in the answer to this question.
Much of ADHD is not yet known, and there is ongoing research being conducted concerning possible genetic factors involved in ADHD.
This ongoing research on the causes of ADHD has many implications in terms of predicting, testing, and treating Attention Deficit Hyperactivity Disorder.
ADHD Tends To Run In Familes
The idea that there are genetic components in the etiology of Attention Deficit Hyperactivity Disorder began with the observation that ADHD tends to run in families.
For example, a child with ADHD is four times more likely to have a relative with ADHD compared to children without ADHD.
Also, if one or more parents suffer from ADHD, their children are more likely to develop the condition. Some studies suggest that at least one-third of fathers with ADHD have children with ADHD.
In addition, comparing adoptive versus biological children with respect to hyperactivity offers much insight into the genetic component of the disorder.
Research indicates that hyperactive children resemble their biological parents more than they do their adoptive parents when comparing symptoms of hyperactivity. (Dr. Dennis Cantwell, UCLA, 1997).
Similarly, studying twins is also informative due to their identical genetic make-up.
A famous Australian ADHD study found that if one identical twin had Attention Deficit Hyperactivity Disorder, the other twin also had ADHD 82% of the time.
This statistically significant correlation among twins raises lots of questions and is certainly cause for more research regarding possible genetic connections and ADHD.
Are There Specific Genetic Markers?
Scientists are even beginning to isolate the specific genes that contribute to the disorder. In particular, the dopamine genes DAT1 and DRD4 have been shown to be associated with ADHD.
Over time, scientists believe they will be able to pinpoint all of the specific gene markers of Attention Deficit Hyperactivity Disorder. This will enable them to fully diagnose, treat, and eventually prevent the disorder.
In 2009, the National Institute Of Mental Health (NIMH) concluded that genetics account for 70 to 80 percent of the risk of developing Attention Deficit Hyperactivity Disorder.
While genetics is not the only cause of Attention Deficit Hyperactivity Disorder (see Causes Of ADHD), it appears that there is a strong genetic component with respect to the etiology of the disorder.