Yes but in your description of an intrusive thought you could still act on it, you just don’t. But I’m sure there are people who at some point have.

I think your last sentence is close to where I sit. In my mind there is plenty of room for overlap between the two. You can have an intrusive thought with out without the impulse to do it. Yes it is distressing, but part of the intrusive thought is that sense of morbid wonder that I have to believe some people have acted on.

Also I’m no psychological expert or anything, I could be way off, it’s just my take.