Being as Adderall is a controlled substance, it might go over better if you start off by saying, "Hey, I know someone who's a lot like me, and he's been diagnosed with ADD without hyperactivity." All ADD meds (ritalin, dexedrine, adderall, concerta, focalin) are similar, except for Strattera, which is not a stimulant.

Age of onset really is a key factor in deciding whether or not someone has it. Sometimes, you have it all your life but you're able to compensate well, until you reach high school or college or a particular job or whatever, but the traits have to have been there all along, since age 7 or earlier. Are there any older relatives who can shed some light on the picture?