ADHD is one of the most common neurodevelopmental disorders in childhood. It is normal for children to have trouble focusing and behaving at one time or another. However, children with ADHD do not just grow out of these behaviors. If your child has trouble controlling their behaviour in comparison to other children their age, he or she may have Attention Deficit Hyperactivity Disorder (ADHD.) If you notice any of these symptoms, have your child evaluated.