THAT's MY DEMON TOO -- obsessive thinking! Whether it's positive or negative, the thoughts distract me constantly! I'm like a "stuck record", replaying the same phrases, unable to process it and move on, or file it in my memory for later.
• No medication decreases my obsessive thinking (yet). Actually, Concerta made it worse.
• Do some research on OCD (obsessive-compulsive disorder). If you identify with any of the definitions/symptoms listed, you might use the same words with your doc or therapist to articulate the struggle.
• Yoga balance exercises and meditation helps -- with regular practice
• Cleaning helps -- anything requiring physical energy takes the edge off
• Writing thoughts in a notebook helps -- but date it, and label the corner of the page so you can reference it later (Experience talking -- I'm attempting to declutter my thousands of obsessive lists and brilliant brainstorms now.)
• MP3 suggestion instantly helps me... I DO like brainsync.com. You might find some free downloads, but I found most free ones even more distracting (obsessing and judging the talent-less use of a cheap synthesizer to layer mu-sack with seagulls).
• Slightly Sane must be aware of "triggers". That's a good thing to be aware of! (Like, trying to avoid irritations or over-stimulation when you need to focus on a task!)
• Last note... When I catch myself spinning off on a tangent (like responding to a post when I should be working), I audibly say, "stop, drop, and roll". (In other words, back to work!)
Hope this helps? Good luck.