Okay... this might sound like a product placement, but those who know me know it's not.

'Fujitsu ScanSnap 1500'. The single best awesome anti-anxiety device ever.

It has freed my mind of paper clutter. Here's a recent IM I had with a coworker. (He has ADHD too)
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Coworker --
BTW: really loving the scanner. Thanks for the advice! It improves aspects of my organizing life I didn't expect

Me--
I know, it's awesome isn't it?

Coworker --
yep. I found that there is a whole sticking point in my willingness to get rid of paper around not being certain whether something might or might not be valuable some day that I discovered was paralyzing
It would turn the whole sorting thing into a disappointment.
But now, if I have that question, I just say: ok, I'll scan it and toss it. And it's gone!

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It's super expensive at 400$, but if you have paper clutter and can stretch yourself a bit, it's so worth it.