Basically, when I got there, I quickly identified a few groups of people. All those people you see on tumblr self diagnosing with schizophrenia, PTSD and OCD, actually end up in mental hospitals sometimes. Everyone absolutely hates them, the other administration, the staff, and especially the people there with real problems. You can tell who's faking it and who's legit, you just have to watch them when they think no one else is watching, also they fill every second of silence with self loathing and fishing for pity, it's actually kind of disturbing.
The second group is the one you think about when you hear the word "Asylum". Absolutely insane, so far gone that you're not even sure what's wrong with them. When the symptoms they display outnumber the list of possible diagnoses. It took some getting used to at first, people crying constantly, laughing manically, and paranoid screams and whimpers, but I couldn't blame them for it at all, after I sort of got past the "omg I'm in a mental hospital" thing, I started to try to talk to and be really nice to these people. Most of them didn't respond in a way that made much sense to me, but I could tell what they meant, they're living in an altered reality, and after a time you can start to understand bits and pieces of this reality. Very sad, some of them had been in there for more than a year, and for most of them it wasn't their first time.
The third group is the one into which I most nearly fit into. The moderates. They're pretty functional until they have bad days, then they're just really distressed. Either extremely sad and teary the whole day, very anxious, or just out of it.
And like you said, you have your drug addicts, nothing too surprising there, when all is said and done, some of them were the most "normal" of the bunch.
We were all given the same treatment with three exceptions
A) A few times a week your doctor would talk to you
B) Your medication was for the most part unique (they had some generics for general problems).
C) The drug addicts went to some sort of off site rehab program once a week, I don't really know anything more specific than that.
Sorry it took so long to do this one, I was eating.