While not everyone in the designated group has each and every correlated problem and characteristic, sometimes researchers find that people assigned to the ADHD group also have other problems in common (i.e., driving problems, anxieties, executive functioning problems, fine motor difficulties, learning problems, failures to complete schooling, “hotheaded” dismissals at work, problems doing homework, and atypical patterns of brain biology and particular genes, etc.). But there are no dysfunctions or biological traits that can be used for diagnostic purposes.
What goes unnoticed, however, is that the ADHD category of people gets transformed into people "having" ADHD. Qualifying for the criteria, magically converts into "having" something (even though nothing in that regard is identified).
So when people say that ADHD is a chronic and pervasive developmental problem, of course it is. The criteria require it to be. And when we find that people qualifying for the criteria have other problems in common, why are we surprised. Quite often people behaving in similar ways, share other problems and traits in common. For example, cab drivers in London are more likely to have a larger visual-spatial cortex because navigating the streets throughout the day develops that aspect of biology. And it would not be surprising if they shared other problems in common as a function of dealing with traffic for long periods of time.
Conclusion: While we are willing to say that people “have” ADHD, it seems peculiar to say that people “have” cab driving. ADHD is a category name, not an explanation even though people use it in that fashion.
Always remember, there might be a variety of precise and coherent ways to account for why a person might qualify for the ADHD criteria, and all of those accounts are theory not fact.