I've omitted the 'h' bit because I'm not at all physically hyperactive (I am, in fact, usually tired...) - but, I'm increasingly having this problem with concentration, and even though it was once limited to things I don't necessarily want to do, lately this results in dozens of half-opened tabs (on subjects that I did initially have much interest for, but soon get tired out, especially if the text is long and my mind soon seems to wander onto other activities that could be regarded as 'instant pleasure'). As such, I always end up procrastinating.
This mostly prevents me from reading beyond the first few pages in a book, which brings me to another thing I'm wondering about - continuation of an activity at a later time. Besides simple forgetfulness, I seem unable to rekindle that interest time and again - this in contrast to that eagerness I remember having as a child, propelling me to continue a video game etc. - but, paradoxically I still have this urge to keep (from the above example) web pages open, until I'd possibly finish reading them four months later.
Also, I seem to notice that even while watching movies etc. I keep having these unrelated cyclic thoughts, mostly worrying about future events - which is why I think I'm unable to concentrate, typically.
So... could this be adut ADD? I didn't even think about it as a child because it didn't bother me at all... but, whatever this is, is now quite disruptive. Although, of course, I'm not sure how much of this could simply be AS.