Just want to echo someone else's sub-thread:
Adderall is not at all similar to Huxley's description of Soma. Soma was about feeling good and not having to think of the evil things that make the BNW society possible, not efficiency.
Also, Huxley's Soma is very close to the medicine Soma (Carisoprodol), in my experience. It's a beautiful, relaxing, euphoric high. Probably highly addictive.