There's a very big drinking culture where I work, and apparently a drug culture as well. They don't drug test here and if you were to walk into the office, you would see lots of bottles of booze on people's desks. Now if you are using during the work day, that might not go so well for you, but they seem to be fine with people boozing in the office after 5pm or so. I would never show up to work with a buzz or anything, but it seems if you can handle yourself here that it's kind of a non issue surprisingly. I don't work in a normal job by any means so my example is not a standard in any way.
When I worked my high school job at Boston Market, the manager asked me to go into the mens bathroom (she was a female) and look behind the toilet without giving me any more information. I looked and found a bottle of vodka. Turns out the cook in the back was a big alcoholic and was drinking on the job. She had smelt it on his breath earlier and was wondering where he was drinking it. That was a real "welcome to earth" moment for me as I had never really seen an drunk at work. I didn't even know he was drunk, but he wasn't a very friendly person so I hardly interacted with him.
As I said before, a time and a place. Drink all you want, smoke all you want, it's not my life but when you cross a boundary such as using in a work place, that's on you.