I read this article at SI.com a couple days ago with the quote "marijuana is almost epidemic." Here's the main point of the article:
According to one veteran club personnel man, 10 or 11 players who carry first-round draft grades on their board this year have been red-flagged for marijuana use in college, an estimate echoed by two clubs' head coaches.
Now I'm sure you're all stunned to learn that there are drugs on college campuses (sarcasm). I think it would have been easier for me to have bought a joint when I was living on campus then it was for me to buy liquor when I was underage. I personally can't stand smoking so it was never my vice (I've had plenty of other vices though...), but I thought this was really the key to the article:
"The kids are admitting it much more now, and part of that is what they've been coached to do [by their agents or handlers],'' one club general manager said. "They want to get the truth out and give you an explanation for their use. That's seen as better than letting someone else put it out there for you and making you look like you were being evasive.
It's not a recent problem. Players are just being upfront about it, and the NFL hasn't cared. Teams are more interested in whether you're honest with them. I don't want the Packers to draft someone with a full-blown substance abuse problem, but I'd have no problem with them drafting someone who admitted that they might have enjoyed college a bit.