As an ADD person who has to take it regularly, I can say that it can just easily focus you on replying to anything of interest on Hacker News... so no, doesn't work this way.
Yeah I've lived it. You have to get to work right away so when it kicks in otherwise you'll generally keep doing whatever you were doing when it did. It can turn you into a god of productivity if you use it right or a degenerate jacking off for 12 hours straight.