I know people who've gotten cannabis cards because they've smoked for so long they can't become hungry without it. I know people who've smoked every night, so they can't fall asleep without it.

When I saw the thread title, I thought you were talking about conditioned responses from the media and anti drug propaganda. Of course there are conditioned responses: I think a lot of the people who act all lame and annoying when they're high do it just because they think that's what marijuana does to you.