I tried this recently. Took 20mg (which is probably 2x average prescribed dose) when I last had to do some writing. As far as I know, addiction is unlikely unless you get carried away. I mean kids are prescribed to take it every day,.

About half an hour after taking it, I started to feel a bit high. I was able to concentrate very intensely one thing , like crafting a sentence. On the other hand, switching between tasks felt more difficult. If I had to look at a source instead of writing, it took me a long time to find and start reading the right page for instance. Also, wicked dry mouth. I babbled to my roommate for a while about random shit and excitedly read her parts of my essay, which I was very convinced was the best scholarship ever. She didn't realize I was high though, so it couldn't have been too obnoxious. The experience was reminiscent of smoking a strong Sativa, but more productive . Fair warning, though, the next day I felt like shit. I had a headache reminiscent of a hangover, and no energy to do anything. I hate hangovers, and this feeling was enough to make me swear off subsequent Adderall experiments.

I definitely would not recommend taking it like I did for school though. You could probably get a prescription easily enough (with health insurance) and see if it helps.