Never tried any of them myself and don't know which they were referring to, but the other replies are probably in the right direction.
Cocaine, MDMA and LSD seem to be favourite drugs around town, here in BC. I mean, besides the usual marijuana, tobacco and beer.
That's interesting. Do you mean Adderall/Ritalin?
That stuff has a relatively fixed useful half-life. It doesn't work for as long as people might think. It also doesn't actually make thinking clearer. It makes people feel as if they are thinking more clearly. I don't feel like looking for it, but this has been studied and reported, somewhere.
If you are referring to crank, well, the half-life of that stuff is even shorter...