I had the anxiety disorder, it was quite fun for a while. At least it's less boring than depression, wouldn't want to suffer from that one. Most difficult part with my anxiety was the fact that for like six months I was 24/7 afraid that I had gone insane and that I'd never be able to live normal life again. Well, I do very well nowadays and I feel uneasy very seldom, usually when I'm really bored and have nothing to do, under the effect of intoxicants, reminded of things associated with my former problems or in some very special situations, like when I see or try to imagine very wide spaces and big distances. Oh, and staring at some surfaces makes me still hallucinate a bit.
To the topic, I think mental illnesses are usually portraited very well and realistically. So well and realistically, that previously I couldn't watch movies or read literature dealing with them without feeling very uneasy. Anyway, making fun of things that are not normal is pretty much the root of all humor, so of course things like the crazy cat women from The Simpsons are usually viewed as funny. You don't find the crazy cat women offending, do you?