Scientists are not sure what causes attention deficit hyperactivity disorder (ADHD), although many studies suggest that genetics plays a large role. Like many other illnesses, ADHD most likely results from a combination of factors. In addition to genetics, researchers are looking at possible environmental factors, and are studying how brain injuries, nutrition, and social environment also might contribute to ADHD.
ADHD and Genes
Inherited from our parents, genes are the “blueprints” for who we are. Results from several international studies of twins show that ADHD often runs in families. Researchers are looking at several genes that may make people more likely to develop the disorder. Knowing the genes involved may one day help researchers prevent the disorder before symptoms develop. Learning about specific genes could also lead to better treatments.
The bottom line: The exact cause of ADHD is unknown, though links to hereditary and environmental factors—such as maternal alcohol consumption and cigarette use—have been identified. Evidence also suggests that brain damage may contribute to ADHD.
Read the NIMH’s “What Causes ADHD?” page for more information.