Experts such as Russell Barkley say ADD and ADHD compound the problem.

CNN: Teen drivers with ADD a problem on the road

Teen drivers with ADD or ADHD "are impulsive, highly distractible and clumsy, can't pay attention to the roadway and they get bored easily, " he said.

CNN: Teen drivers with ADD a problem on the road

Whichever term you use, the important point to know is that you can have ADHD (or ADD) without showing any signs of hyperactivity or impulsivity whatsoever.

NPR: Excerpt: 'Delivered from Distraction'

In addition to the history, which should include questions based upon the DSM-IV diagnostic criteria, and the qEEG and sometimes the SPECT, other standardized sets of questions, such as the ADHD Rating Scale or the Brown scale, add confidence to the diagnosis.

NPR: Excerpt: 'Delivered from Distraction'

Technically, this means you can have ADHD with no symptoms of H, hence there is no need for the term ADD.

NPR: Excerpt: 'Delivered from Distraction'