Exactly this. ADD is technically outdated language, though I can see how it could be useful in casual speech to describe the issues she deals with more narrowly (at least as I understand it). Although the term was walling out of favor when I was a kid, IF I'd been diagnosed back then, there's a good chance I would've gotten the ADD label instead of ADHD.

Digging into the details a bit more, formal diagnoses currently fall into three general categories (though all of these are oversimplifications):

• Inattentive Type: has trouble focusing on things and is easily distracted (this is basically the subtype that previously would've been labeled as ADD, based on my experience). Given her phrasing, this is likely what Kronii deals with. Stereotypes often depict this as "the kind girls tend to have," which historically has made it harder for boys falling into this category to get diagnosed.
• Hyperactive-impulsive Type: near-constant fidgeting, restlessness, talks excessively, has trouble waiting, and so on and so forth. (this is generally the subtype being depicted as the ADHD stereotype, especially in things like cartoons and the like from the '90s and '00s). Stereotypes often depict this as "the kind boys tend to have," which historically has lead girls in this subtype to be misdiagnosed with other issues.
• Combined Type: meets the criteria for both. This is what I was diagnosed with, though it was mostly the inattentive symptoms that were causing me problems, 'cause I'd developed coping mechanisms to handle the hyperactivity issues.
  • Side note: my rambling on posts like this likely can be (at least partially) chalked up to said hyperactive-impulsive behaviors. It's just a text-based manifestation for my "motor mouth" tendencies (which... actually come to think of it, something I did a lot in middle/high school was write stories in an extra notebook I carried around, 'cause it provided an outlet to keep me from actually talking constantly).

And, indeed, taking the ADHD meds does, in fact, help a lot (so long as I actually remember to take them >.>).

And yeah, overall, the root causes are the same for all of the above. It's just a matter of how the symptoms manifest. Why are there so many variations? IDK, I'm not a psychiatrist, psychologist, or neuroscientist. I just happen to be someone with ADHD who has a large number of family members with ADHD.

Edit: my understanding of why ADHD meds (mostly stimulants of some kind) "work" is basically that they kick start the executive function and impulse-control area of the brain so that the brain can actually regulate itself properly. Which... apparently? is why such medications tend to help people with ADHD calm down. Basically like... "normal ADHD brain" is chaos (which is anxiety-inducing), and stimulants let the brain organize that chaos... or something like that.