[lttlrck]

Why should you even know they were not clean at some point in their past. And what about the future?

Like the sibling comment, I find this very sad.

Perform drug tests if you're worried.

[qkls]

I'm imagining a scenario where a candidate explicitly says that they just had a career break that was due to drug abuse, I think it would be hard to stay objective after that. I don't hire people but that would affect a lot of employers.