Hi man,
Just wanted to refer you to an article that I wrote about Depression. I know you're not depressed, but I was a social worker with kids who had ADHD. Difficulty concentrating, racing mind sometimes. Drugs are not the answer unfortunately.. I'd advice you to check out this article about excitatory symptoms as ways the body is trying to release toxins from repressed emotion. It was absolutely fascinating and it's helped me quite a bit.. Here is the link, possibly try it, and see what happens....
A Cure for Depression | Jumping Ship Happens