ADHD people live under such stress, frustration is difficult to tolerate, and when they're frustrated they're likely to become angry.
Not all children who are naturally rambunctious or extraordinarily curious have ADHD . . .
Nor do all disorganized adults who have many things going on at one time have ADD . . .
A high level of frustration causes ADHD people to be impatient. Whatever is going on -- they want it to go quickly and be finished.
People with ADHD suffer from "overload"; they have a heightened awareness of incoming environmental stimuli. Their world tends to be too bright, too loud, too abrasive and too rapidly changing for comfort.