The exact causes of ADHD are not known with certainty.
Experts do know that ADHD has a strong genetic component. In addition, they think that genes that control the levels of certain chemicals in the brain called neurotransmitters seem to be different in those with ADHD.
In some cases, though, there is no genetic link to ADHD, but other common behaviors, such as smoking or drinking during pregnancy, as well as other obstetrical complications have been linked to ADHD in children.
Babies with low...