I work in a major software corporation and have literally never seen or heard of drug use at the company, outside of non-work-related recreational drug use (and even that never ventured very far). Perhaps it's the stability of being at a fortune 100 company.

Those who work here went through a pretty intense interview process. They're pretty good developers, which means if they were fired it wouldn't take them long to find a job. So why bother taking performance enhancing drugs?

Of course, the coffee and sugar is readily available and free.