The formal name for hyperactivity is attention deficit disorder. Causes Doctors do not know the exact cause of most cases of attention deficit disorder. A few children with the disorder have suffered brain injury before birth or sometime afterward, and a small number have severe psychological problems. Some other cases have been linked to hereditary factors, but no satisfactory explanation has been found for the majority of cases. Incidence Only a small percentage of children are hyperactive.
Boys tend to have the disorder more often than girls.
Though a child may exhibit symptoms from a very early age, attention deficit disorder is often not diagnosed until the child reaches school age. Symptoms you are likely to notice Recognizing the presence of hyperactivity in young children can be difficult. Levels of physical activity normally vary among children, and some children are very active without being hyperactive. As a rule boys are more active than girls. With hyperactive children the level of activity is especially high.