Almost all children have times when their behavior veers out of control. They may speed about in constant motion, make noise nonstop, refuse to wait their turn, and crash into everything around them. At other times they may drift as if in a daydream, failing to pay attention or finish what they start.
However, for some children, these kinds of behaviors are more than an occasional problem. Children with attention-deficit/hyperactivity disorder (ADHD) have behavior problems that are so frequent and severe that they interfere with their ability to live normal lives.