Sorry, I should've clarified. By no means do I think it's acceptable to be interacting with patients when you're high, I just meant when you're not with patients.
I think you and I clearly agree on this issue outside of the use of marijuana, which, as you said, is another debate. Random drug testing of dental students for amphetamines (I would like this simply because it would root out Adderall use among people without a Rx), barbiturates, narcotics, amphetamines, Rx drug abuse etc, would be something I could definitely support, at least in theory. The problem is that tests do not detect use from as long ago as they do for marijuana. So if somebody lucks out and has their random drug test two weeks after they were using while working on a patient, it goes undetected. Schools could use their own discretion and judgement to overlook a marijuana positive if that's the only thing that came up on the screen; I just think that in today's world, many of them wouldn't look past it.
I just have a problem with the demonizing of marijuana use/users (not accusing you of doing this nor implying you hold these views). Ideally, every car in the world would come with one of those breathalyzer things that prevent the car from starting if you blow over a .08. Having a breathlyzer when you enter/exit your office (dentist) or hospital (nurse/PA/APRN/physician) would definitely keep people safe, and in an ideal world it would exist and I'd support it. This will probably will never happen though, as safe as it would keep us. I guess your point brings up a larger debate of personal liberties vs safety that I'd be glad to discuss back and forth, as I find it very interesting.
Moral of the story: Yes, there are instances where people have struggles with drug addictions that clearly jeopardize patient safety. I would definitely advocate for ways to catch offenders and keep patients safe without penalizing health care providers for what they do on their own time that in no way, shape, or form harms patients.