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.

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.

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.