A couple of years after this article a book about Erdős appeared called My Brain is Open. If you enjoyed this article I highly recommend the book about this fascinating man and his unique life. It even has some good explanations of some of the problems he worked on.
The information about amphetamines made an impression. His friends at times tried to discourage him, but he claimed that without them, he could create no mathematics. Given his colossal output, this means that a significant part of the landscape of modern mathematics owes it existence to this drug.
How he learned the drug would help him, and how he got his hands on it, and when and how his use of it started, are questions I'm very curious about, but the book doesn't go there.