Or at least, this ADD writer can't pants a story.
Because to my ADD brain, pantsing is the equivalent of a bird migrating without an internal compass, or writing without any pants on. Left to its own devices, my brain fails to keep plot and characterization well-focused, self-explanatory, and consistent. My thoughts are just not organized enough for that. Worse, once I type up and edit up too much of a story, the story becomes set in concrete. And there are few things I hate more than cracking it, grinding it down to powder, and pouring it into a new mold.
That means I need to learn to do it right the first time. And I need to learn from my mistakes (like I am doing here, thank God).
That being said, however, there is one area in which I can still pants. And that is the idea stage, when I'm trying to figure out what story to tell. A few paragraphs, a snippet, a vignette--all of these can give me material to work with, a concept I can now whip into the proper shape with some hard planning.
And you know what? It's still fun. You just spread your fun out. There is a lot of pleasure to be found in discovering what comes next, in being surprised by your characters or story or the world you are creating. Pantsers derive most of that pleasure as they write. But as an outliner, the pleasure comes in big doses during the planning stage and small doses during the writing stage. After all, even with the strictest outline, I still have had character or story or world surprise me in some small way.
So in a nutshell, my advice to writers with ADD and even to those without? Know your strengths and weaknesses, and then make sure you work from a position of strength, not the easy way or the way peer pressure guides you. Work your way, and you will make your own success the first time around.