Be careful with those as well, esp. if you have an addictive personality. Way back in the 90s, I often consumed something that is very close in composition to Adderall, but stronger. From what I've heard Adderall can be very addicting as well. Not to mention, I have had students in my university classroom, tell me that the work I assign is no problem once they rail a couple of Ritalin.
Sorry, I sound more like a mother, but just so its clear, I'm not a doctor and this is not a doctor's advice.