Attention Deficit Hyperactivity Disorder (ADHD) is a condition that
becomes apparent in some children in the preschool and early school
years. It is hard for these children to control their behavior and/or
pay attention. It is estimated that between 3 and 5 percent of children
have ADHD, or approximately 2 million children in the United States.
This means that in a classroom of 25 to 30 children, it is likely that
at least one will have ADHD.

For more information visit :-
http://www.medical-health-care-infor...pedia/ADHD.asp