The exact cause of ADHD is unknown but it is known to run in families and there are a number of differences in the brain that can be identified in people who have the condition compared to people who don’t. ADHD can run in families and the genes that are inherited from parents are a significant factor in developing the condition. Both parents and siblings of a child with ADHD are more likely to have ADHD themselves.
There are other factors that can contribute to having ADHD such as being born prematurely or having a low birth weight along with drug abuse, alcohol or smoking during a pregnancy. Other things could include brain damage either in the wound or in the first few years of like or exposure to high levels of toxic lead in the first few years of life.