ADD used to be a separate diagnosis, but now they classify both as subtypes of ADHD: Primarily Hyperactive or Primarily Inattentive. I'm ADHD-PI and can't relate to stereotypical hyperactivity at all.

Hyperactivity in adults is often masked or internalized. If you keep yourself tapping a rythm, bouncing your leg or repeating some tune in your head over and over you might just qualify for further diagnosis.

Not everyone is hyperactive.

ADHD is the whole spectrum, each individual presents differently, with more/less of each attribute.

ADD is a subtype. Last I read there were a number of subtypes, sort of a matrix of attributes.

It took them years to figure it out with me. I was in high school in the mid 90s before they diagnosed me with ADD, and gave me a prescription of Adderall and unleashed me on university a year later.

I wish I had been able to be medicated a bit longer, but the few years I had it gave me some good habits.