What Is Attention Deficit Hyperactivity Disorder (ADHD)? Many people have heard of ADHD. It may make you think of kids who have trouble paying attention or who are hyperactive or impulsive. Adults. Dec 29, · Attention-deficit/hyperactivity disorder (ADHD) is a disorder marked by an ongoing pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development.