How Do You Bring Up Something like Adderall with Strict Parents?

So, I am 17 and my parents are very strict—an example is that I was grounded for 5 months for dying my hair black without their permission. They are very old-fashioned in their manners and ways of thinking. They don’t believe in things like ADD, ADHD, Bipolar Dissorders, or anything of that persuasion; and their views on the medications provided for these maladies are that they are an excuse for people to complain and take unneccessary perscriptions.
I have never done exceedingly well in school, even though I put my all into my work. When my friend (who’s the most brilliant girl I currently know) told me how when she hadn’t been doing well in school; she tested for ADD and ended up testing positive. Now that she has it treated, her grades have taken a 180 and she’s doing well to the point of taking all honors classes.
I became curious about what ADD was and I did research on it. After comparing my complications to the effects of ADD, I am certain that I have it.
Now how do I bring something up that’s so contrary to my parents opinions, to get them to see that I should take a test to see if I do infact, have ADD?
(Please, no lecturing. If I wanted to be lectured I wouldn’t have posted this. I am simply looking for helpful, well-meaning advice on how to approach my parents with this dilema in a respectful way.)
Thank you :)