Is it possible to have ADHD without being impulsive?

Yes, absolutely. Impulsivity is only one possible part of ADHD, and many adults don’t experience it strongly at all. ADHD has different presentations. Some people are more outwardly impulsive or hyperactive, while others are primarily inattentive. Adults with the inattentive presentation are often described as scattered, forgetful, mentally busy, or chronically overwhelmed rather than impulsive or risk taking. In adults especially, impulsivity often changes form. Instead of obvious behaviors, it may show up as mental impulsivity, like jumping between thoughts, difficulty finishing tasks, interrupting internally, or making decisions quickly to escape discomfort. Some people don’t experience even that. Clinically, we don’t require impulsivity for an ADHD diagnosis. Difficulty sustaining attention, organizing, starting and finishing tasks, managing time, and regulating mental focus are enough when they’re persistent, impairing, and longstanding. Many adults who aren’t impulsive were actually praised growing up for being quiet, compliant, or well behaved, even while struggling internally. Their ADHD went unnoticed because it didn’t disrupt others. So yes, being scattered without being impulsive can very much fit ADHD. The absence of impulsivity does not rule it out.