In my experience as a biology/chemistry teacher, the ones to watch for dodgy behaviour were the teachers who didn't use any recreational drug (I include alcohol & tobacco in that grouping); it's a stressful job, especially when the government keeps moving the goalposts/putting more paper pushing etc on teachers rather than actually letting them teach & as such, teachers who didn't use something as a form of release at the weekend were the ones most likely to be involved in something like assaulting a kid (I have witnessed that happen twice - never a serious assault, more grabbing a kid and pushing them up against a wall while issuing threats if they continue to misbehave, but both times the teacher losing it was a teetotal, religious sort), or worse. Admittedly in the majority of cases the intoxicant was alcohol (I've seen the head of science, who was a really good teacher, at the last school I taught at so shitfaced at the xmas party that he was probably more pickled than the specimens in the biology prep room
), but there was always at least a couple of science teachers (other than me!) who induged in more exotic substances and to be quite honest they had a much better relationship with the kids and as a rule got some of the best work from the kids purely through being more open minded.
I fully agree that anybody who repeatedly comes into work intoxicated shouldn't be in such a responsible position, but if I had kids, I'd much rather their teachers were open minded and say took psychedelics at the weekend than never took anything, but were so tightly wrapped that they were a ticking time bomb, as the latter seem to discourage any thinking/discussion outside the very narrow confines of their subject. I only have to remember one of the two teachers I mentioned above trying to have a lesson about reproduction in humans and it being a travesty due to their anally retentive & uptight demeanour because it involved sex (it was a catholic school, so you can imagine what sort of fucked up affair it was having a guilt ridden devout catholic trying to explain sexual behaviour to 15/16 year olds. It would have been hilariously funny if it wasn't so bloody serious)