Adderrall is speed. It works for a brief period, but the cost even for brief use is high. And, whether they call it "meth" or prescription drugs it's addictive as hell. I did a gig in an area and industry where this sort of prescription drug abuse is rampant. It was so bad we had a hard time finding people that could even pass a dope test. But the dope tests apparently can be beaten because half the folks that made it to the job were on adderrall. Probably they had a prescription.
One guy just did it a couple of times--he got the job done by working about 30 hours straight. I didn't know he was high, but figured it out later. After his 30 hour work binge he was out "with the flu" for a day. When he got back after his day off, he still looked like he'd had the crap beaten out of him. This guy was a project leader and took it on himself to 'get it done no matter what'. Last I heard, he figured out that 'no matter what' was way too high a price and wasn't using. Boss agreed wholeheartedly--he'd rather explain failure to deliver than abuse his people. Good boss. When the abuse got too bad he walked us all off the job--you don't treat human beings that way and we were very lucky to have a boss that stood up for us.
Another guy was a more experienced user, and looked like he could maintain. Unfortunately he had the attention span of a gnat. I was ordered by the boss to finish up some of the guys work and as I went through the job I could see where he'd started on one task, then just abandoned it before it was done and jumped into the next task. The whole job was like that. It was easier to scrap it and do it myself than to try to figure out what was done and not.
A third guy just had no focus left at all. Also an experienced user. I'd give him a job to do, come back in a couple hours and he's gotten nothing done. I'd demonstrate the job again and return again; the only part that was completed was what I'd shown him. This guy was so burnt as to be inert. I suspect he was on a little more than just adderrall as he acted a little different.