Attention Deficit Disorder Approximately 3-5% of all American children have an Attention Deficit Disorder (ADD). ADD is a leading cause of school failure and under-achievement. ADD characteristics often arise in early childhood. As many as 50% of children with ADD are never diagnosed. Boys significantly outnumber girls, though girls are more likely to be undiagnosed with ADD. "ADD is not an attention disorder, but a disorder of impulse control ( Seminar notes Barkeley) ." Characteristics of Attention Deficit Disorder can include : Fidgeting with hands or feet , difficulty remaining seated, awaiting turns