ADHD (Attention Deficit Hyperactivity Disorder)
Is ADHD Genetic?
Attention Deficit Hyperactivity Disorder
Attention deficit hyperactivity disorder (ADHD) is a neurobehavioral disorder. It’s most commonly diagnosed in childhood, but adults can experience the symptoms of the disorder and be diagnosed, too. According to the American Psychiatric Association, 9 percent of school-aged children have ADHD. Their statistics also show that 4 percent of U.S. adults have ADHD. The most common symptoms of ADHD include an inability to focus, fidgeting or squirming, avoiding tasks or not being able to complete them, and being easily distracted.
What Causes ADHD?
Researchers have been unable to identify a single cause for ADHD. A combination of genes, environmental factors, and possibly diet seem to influence the likelihood a person will be diagnosed with ADHD. Many studies suggest genes are the largest factors in determining who develops ADHD and who does not.
After all, genes are the building blocks for our bodies. We inherit our genes from our parents. Like many disorders or conditions, ADHD may have a strong genetic component. For that reason, many scientists focus their research on the exact genes that carry the disorder and how they can be treated.
One Close Relative
Having a family member with ADHD makes you more likely to also have the disorder. Children who have ADHD typically have a parent, sibling, or other close relative with ADHD. In fact, according to the National Institutes of Health one third of fathers who have or had ADHD will have children who will be diagnosed with ADHD.
Twins share lots of things: birthdays, secrets, parents, and grades. Unfortunately they also share the risk of having ADHD. According to Australian researchers, twins are more likely to have ADHD than singletons. Additionally, a child who has an identical twin with ADHD has a three in four chance of also developing ADHD.
Unlike potential environmental causes of ADHD, DNA cannot be changed. As research has narrowed in on what causes ADHD, scientists recognize the strong role genetics play. Therefore, much of the research into ADHD is devoted to understanding genes. In 2010, British researchers identified small pieces of DNA that are either duplicated or missing in the brains of children with ADHD. These affected genetic segments have also been linked to autism and schizophrenia.
Thinner Brain Tissue
Researchers with the National Institute of Mental Health identified an area of the brain that ADHD may affect. In particular, the scientists found that individuals with ADHD have thinner tissue in the areas of the brain associated with attention. Fortunately, the study also found that some children with the thinner brain tissue develop normal levels of tissue thickness as they got older. As the tissue became thicker, the symptoms of ADHD were not as severe.
Additional Risk Factors for ADHD
Besides DNA, other factors can influence who develops ADHD. These risk factors include:
- environmental exposure: Exposure to lead may increase a child’s risk for ADHD.
- brain injury: A small number of children who suffer a traumatic brain injury may develop ADHD.
- a mother’s alcohol and tobacco use during pregnancy: A study by the Washington University School of Medicine found that mothers who smoke while pregnant increase their child’s risk for developing ADHD. Women who drink alcohol and use drugs during pregnancy also put their child at risk for the disorder.
- low birth weight or premature delivery: Babies born before their due date are more likely to have ADHD when they are older.
For Parents with ADHD
You may be worried about passing the genes for this disorder to your child. Unfortunately, you cannot control whether your child will inherit the genes for ADHD or not. But you can control how vigilant you are about your child’s potential symptoms. Be sure to alert your child’s pediatrician to your personal history of ADHD. The sooner you are aware of potential signs of ADHD in your child, the sooner you and your child’s doctor can respond. You can begin treatment and therapy early, which may help your child learn to cope with the symptoms of ADHD better.
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- Attention-Deficit/Hyperactivity Disorder (ADHD) – Facts About ADHD. (2013, April 18). Centers for Disease Control and Prevention. Retrieved June 7, 2013, from http://www.cdc.gov/ncbddd/adhd/facts.html
- Attention-deficit/hyperactivity disorder (ADHD) in children. (2013, March 5). Mayo Clinic. Retrieved June 14, 2013, from http://www.mayoclinic.com/health/adhd/DS00275
- Attention-Deficit/Hyperactivity Disorder, Research. (2012, September 28). Centers for Disease Control and Prevention. Retrieved June 7, 2013, from http://www.cdc.gov/ncbddd/adhd/research.html
- McDougall, M.R. et al. (2006, February). Having a co-twin with attention-deficit hyperactivity disorder. Twin Research and Human Genetics, 9(1), 148-154. Retrieved June 7, 2013, from http://www.ncbi.nlm.nih.gov/pubmed/16611480.
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- The ADHD Genetic Research Study at the National Institutes of Health and The National Human Genome Research Institute. (2012, November 15). National Human Genome Research Institute, National Institutes of Health. Retrieved June 14, 2013, from http://www.genome.gov/10004300
- Williams, N.M. et al. (2010, October 23). Rare chromosomal deletions and duplications in attention-deficit hyperactivity disorder: a genome-wide analysis. The Lancet, 376(9750), 1401-1408. Retrieved June 7, 2013, from http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(10)61109-9/abstract