Isn't ADHD just "hyperactivity" — if I'm not hyperactive at all, does that mean I don't have it?

Exact same reaction when I got diagnosed, kept saying 'but I'm not hyperactive' to my provider like it disqualified me. Turns out I'm plenty 'hyperactive' internally, just none of it shows up physically, it's all racing thoughts I'd never connected to ADHD before.

Hyperactivity is one presentation of ADHD, not the defining feature of all of it, which is honestly one of the most common misconceptions out there, largely because the hyperactive-type presentation is the most visible and the one pop culture latched onto. There are actually a few recognized presentations: hyperactive-impulsive, inattentive, and combined type, and inattentive-type ADHD can look almost nothing like the stereotype, quiet, still, seemingly 'spacey' or distracted rather than bouncing around. What inattentive-type actually looks like day to day: trouble sustaining attention on tasks, difficulty organizing, losing track of things, seeming to not listen even when someone's directly talking to you, forgetfulness in daily activities. None of that requires any outward physical restlessness at all, the 'hyperactivity' in this presentation, if it's there at all, is often more internal, racing thoughts, mental restlessness, rather than visible physical movement. This is exactly why inattentive-type tends to get missed or diagnosed later than hyperactive-type, quiet, still kids don't get flagged by teachers the way disruptive, can't-sit-still kids do, even when the underlying attention regulation issue is just as real and just as impairing. So no, being physically calm doesn't rule it out, your assessment is looking at attention regulation and executive function broadly, not just whether you fidget.