Welcome to the Candy Shop! No, not really, but that is what it feels like sometimes in the restaurant industry. Personally, if you need it for medicinal purposes, go for it. If you are using it to get high, well like the title says "Stupid is as stupid does."
You can divide up the employees in percentages. 60% do drugs, 20% sell and do drugs and the other 20% are actually people who love the restaurant industry. It is nothing to come into work and see co-workers strung out. Alas, not everyone can tell. Some people are so adept at hiding it, you as a guest would never be able to tell.
Example: There is one girl at my work in particular. When you see her at your table, she is kind, friendly, bubbly and very adept. But when she comes in the in door, look out. She is so wound up so tight, I do believe her head will pop off one day. I am serious. At first glance, she is sweet and considerate, but after you work with her for a week, you want to strangle her. Literally. God forbid you tick her off. Once she is pissed, she doesn't shut up. I had to work with her one night that someone, early in the shift, made her mad. She in turn, drove the rest of us crazy. She ranted and raved to everyone that would listen in earshot. If there wasn't anyone, she would constantly talk to herself. She reminds me of one those old fashioned wind up toys. (See picture above) Except all you have to do to wind her up, is push her buttons the wrong way. She is a prime example of someone who needs to lay off the uppers.
Personally, if I am going to be stuck with someone doing drugs, I would rather work with the potheads. All they do is loaf off and nibble on every single thing they can get their hands on. They only make me want to choke them on the weekends. Those are the days when doing side work is most important. They will take the last knife and instead of getting more, they will stand around and talk. Standing pretty much everyplace you need to walk in.
Just to let you know, not all of them do illegal drugs. Some of them drink. Life is always interesting in a restaurant. Basically, I work in a three ring circus. I can only thank the stars that I am not the Ringmaster.