I don't know anything about kratom. If you can legally sell it to enhance mental performance, be my guest. We aren't discussing herbs, though. We are discussing use of medicines prescribed for ADD by people without that condition in order to increase mental focus.
Regardless of your, my, or any other opinions on the matter, the fact is that use of prescription drugs for purposes other than which they are prescribed is illegal. That is my whole point. Doctors get into trouble all the time for writing scripts for pain killers to abusers in exchange for money (or sex). Don't blame me if you don't like the law; I didn't enact it.
BTW, in the same thread, I provide links to research on the long-term effects of Ritalin, a Schedule II drug. Most of the results indicate long-term abusers suffer effects similar to cocaine abuse and depression.