Attention-deficit/hyperactivity disorder (ADHD) is marked by an ongoing pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development.
Inattention--wanders off task, lacks persistence, has difficulty sustaining focus, is disorganized. These problems are not due to defiance or lack of comprehension.
Hyperactivity--seems to move about constantly, including in inappropriate situations. May excessively fidget, tap, or talk. Adults may show extreme restlessness.
Impulsivity--makes hasty decisions without first considering consequences or potential for harm. May exhibit a desire for immediate rewards or an inability to delay gratification. May be socially intrusive and excessively interrupt others.
ABA is also an effective behavioral intervention for other disorders (Oppositional Defiant Disorder (ODD), Obsessive-compulsive Disorder (OCD), for example).