Attention Deficit Disorder (ADD) and Attention Deficit/Hyperactivity Disorder (ADHD) are diagnoses applied to children and adults who consistently display certain characteristic behaviors over a period of time. The most common behaviors fall into three categories: inattention, hyperactivity, impulsivity . People who are inattentive have a hard time keeping their mind on any one thing and may get bored with a task after only a few minutes. People who are hyperactive always seem to be in motion. They can't sit still and may feel constantly restless. People who are overly impulsive seem unable to curb their immediate reactions or think before they act.