[rizzom5000]

Well, it may be confusing to some that one of the most, if not the most, prolific mathematicians of modern times accepted, and even embraced, what would be in modern times, the use of a substance that would make said prolific mathematician a felon (at least in the US).

Also, Wikipedia, while generally good, is likely not good to use a definitive source.

[raverbashing]

Wow, a felon?

Millions of americans take amphetamines or similar substances every day legally, by the name of Ritalin, Adderall and others.

[xtqctz]

Nature published an informal survey several years ago on amphetamine use among its readership. Perhaps you'll find it interesting:

http://www.nature.com/news/2008/080409/full/452674a.html

[jhales]

This is well accepted. Also,Erdos was and is far from alone in this.