Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder. It’s most commonly diagnosed in childhood, but adults can experience the symptoms of the disorder and be diagnosed as well. According to the American Psychiatric Association (APA), an estimated 5 percent of children and 2.5 percent of adults in the United States have ADHD. The most common symptoms of ADHD include:
- inability to focus
- fidgeting or squirming
- avoiding tasks or not being able to complete them
- being easily distracted
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 of a person developing ADHD.
Some research suggests genes are the largest factors in determining who develops ADHD. 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.
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 (NIH), at least 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 an Australian study, twins are more likely to have ADHD than singletons. Additionally, a child who has an identical twin with ADHD has a high chance of also developing the disorder.
Unlike potential environmental causes of ADHD, DNA can’t 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.
Researchers with the National Institute of Mental Health (NAMI) 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 developed normal levels of tissue thickness as they got older. As the tissue became thicker, the symptoms of ADHD became less severe.
Besides DNA, other factors can influence who develops ADHD. These include the following:
- Environmental exposure, such as exposure to lead, may increase a child’s risk for ADHD.
- A small number of children who suffer a traumatic brain injury may develop ADHD.
- This study 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.
- Babies born before their due date are more likely to have ADHD when they’re older, according to this study.
You may be worried about passing the genes for this disorder onto your child. Unfortunately, you can’t control whether your child will inherit the genes for ADHD. However, 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’re 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 better cope with the symptoms of ADHD.