This depends heavily on a number of things, mostly the intent behind using a disorder as an excuse.
Firstly, if we're talking about someone who's not actually diagnosed and/or just straight-up lying? Then that is 100% not ok. Just... just no. Stop. What you're doing is absolutely awful and you don't deserve any of the pity you're getting. Also, you're the reason why there's so much stigma preventing people who actually have these disorders from talking about them. If you're not diagnosed but you think you have a mental disorder, then don't say "I have X disorder", say, "I think I might have X disorder". And go see a professional about it. Don't self-diagnose, and, if for whatever reason the topic comes up before you see a professional, or you see a list of symptoms online and think it describes you, then don't say "oh, I must have this", say, "I think I could possibly have this, because it would explain a lot", and let a professional take it from there if you're really concerned about it. I don't see anything wrong with someone simply stating that they think they have a certain disorder, so long as it's stated as a mere possibility as opposed to fact (and assuming it's relevant to the conversation at hand). Just... be honest, and don't lie/self-diagnose. That's rule #1.
As for the rest, I'd say it has to do with the intent of it. If you're bringing up your disorder expressly for the purpose of getting pity points or feeling like a special snowflake, then, yeah, that's dickish. But, if you're just being honest about when your disorder is making it difficult to do something, then... I don't know why that's something to be shamed. In fact, personally, I often worry that any mention of my disorder might come across as just "doing it for attention" (or at least, I used to be a lot more worried about it -- I've recently built up a bit more confidence in that regard) when I'm really not trying to do that sort of thing.
For example: I've mentioned my ADHD around here before. If I were to summarize my experiences with it in a nutshell, it basically means that I have a hard time staying focused on specific things -- especially things that require a fair amount of mental effort, like schoolwork -- and I have a tendency to zone out a lot when trying to do these things, which can sometimes make it feel nearly impossible. Because of this, it's hard for me to write IC posts and do a lot of other GM stuff when I'm not medicated. Sometimes even relatively simple things like responding to a PM from a co-GM or reading over a CS can be too hard for me, because I just can't stay focused enough on the task at hand to really absorb all the information. So, if it's late at night and my medication has worn off, and someone posts a CS for me to read, I'll try to give it a look-over, but, there's a very good chance that I just won't be in the right state of mind to give it a close read or a thorough response. So, I might say to that player, "I'll look at it tomorrow", and I might even add something like "I just can't concentrate on reading it right now". But, then there's the fact that I'll probably still be online and doing less thought-intensive things, and I don't want to look like I'm lazy -- ignoring their CS and claiming to not be in a good state of mind to read it when I'm still capable of being online and doing other things. I could use my disorder as an explanation as to why I can't give a CS a close read and solid response, but then, I don't want to sound like that guy who uses a disorder as a free pass to be lazy. So, it often leaves me wondering, which is worse? >.<
In general, I just try to be honest. If I'm not feeling up to something and I think it'll be hard for me to stay focused, I'll tell people that. If I feel like I need to clarify why exactly I have problems staying focused, then, I will. Because, yes, it's true that a disorder doesn't define a person, but it does make certain things more difficult for them. That's kind of what makes it a disorder. Expecting people to never be limited by their disorder is like pretending that it doesn't exist, and I don't think that's really helpful to anyone, either. I see nothing wrong with being honest about when something is difficult for you. After all, if you were sick (and I mean sick enough to stay home from school/work), and you realized it was your turn to post on one of your roleplays, but didn't feel up to it, I think your partner/GM would be understanding if you just told them the truth about why you couldn't post. And I don't think they'd take much issue with seeing you lurking around GC, either, since writing an IC post takes up a lot more mental effort than a one-sentence comment on a GC thread, and you have a very good reason to be feeling too fatigued to write an IC post, especially since the understanding is that you'll be feeling better at some point and you can tackle that post then.
Now, if you were using your sickness as a way of fishing for pity points/special treatment, or you were exaggerating about how sick you were and just wanted to use a mild cold as an excuse for not posting, or you were completely lying about being sick to begin with, then that would be dickish. But, honestly being sick and not feeling up to posting? You have every right to use that as an excuse. I don't see why mental illnesses should be treated any differently from physical illnesses in this regard. If you're not feeling well then you're not feeling well, and, so long as you're not being an absolute dick about it, I don't see why it should be wrong to just be honest about what the problem is.
I think what bothers me the most about all of this is how people often assume that people only bring up their mental disorders when they're trying to be manipulative or attention whorish about it, but, I don't think that's a lot of people's intentions. I know I often worry that I'm coming across as such when I really don't mean to, and I'm probably not the only one. I just wish there wasn't so much of a stigma around it.
To give another personal example: I'm in a LARP group (currently on hiatus, going to start up again during the spring semester), in which, one complaint the GMs' had from last semester's sessions was how they felt that the players weren't paying enough attention to things that were going on. And, every time they brought it up, I felt guilty -- because I was one of those people who wasn't paying enough attention. Except, I was really trying to. I really wanted to stay focused. But, that isn't always within my control. I can recall one night where it was really bad -- there was this battle going on, and, every time it was my turn to do something, I had to ask the GM's what was happening and where everyone was, because I just couldn't focus well enough to keep track of it all. I apologized plenty every time I had to ask, though, because I knew how much the GM's were annoyed by this sort of thing already, and I really didn't want them to think that I just wasn't putting in the effort. Recently I've been debating whether or not I should mention my ADHD to the GM's, just to tell them that I really am trying to stay focused and that I'm sorry if my disorder makes me zone out for a second and miss some important information. Trouble is, once again, I don't want to sound like I'm just using my disorder as an excuse. And, I don't know what would be worse -- not saying anything and making them think I'm one of the players who isn't putting enough effort in, or telling them and making it sound like I'm trying to be a special snowflake? And, if I did tell them, would I be expecting special treatment? Would they interpret it as me asking for special treatment, or at least a special pass giving me an excuse to have information repeated to me because I missed it the first time? And if I don't actually suggest anything they can do to make it easier for me, would I just be perceived as wanting pity points?
I really wish I could just give people a simple, honest explanation for these things -- something a bit better than "sorry, I'm really out of it right now" -- but it's the nuance surrounding all this that makes me hesitate to be honest about it, making me feel like I have something to hide, when, really, why should I feel that way?
tl;dr -- I feel like there's a difference between "Sorry, I really am trying, but my disorder is making it difficult to do a certain thing" and "I have a disorder so I shouldn't be expected to do that thing". The former implies that you're making an effort but, unfortunately, your disorder is being too difficult to deal with. The latter is what sounds like an excuse and a free pass for not doing anything. The latter is, yes, dickish -- but I don't like the fact that there's so much stigma surrounding the latter that the people who want to say the former feel like they can't. :/
As for expecting other people to conform to your needs -- that also depends a lot on the situation, but, I'm not really that against the idea of it as much as some other people here. First, it depends on just what you're asking of them. Obviously, some things are more reasonable than others. But, if it's just a small thing? I really don't see the problem in being a little considerate and trying to do things that'll make their life a little bit easier, especially if it doesn't take much effort on your part. Secondly, it depends on who it is that you're asking these kinds of things from. Complete strangers? Yeah, it might be a bit much for you to expect that from them. Friends/acquaintances? That might be a lot more acceptable. And then, of course, there's just how you go about it. If you explain your disorder and politely ask that someone does/doesn't do a certain thing for you to make things easier for you, then that's a lot better than demanding that people do what you say and acting as if they're in the wrong for not conforming to your needs. One of these things is a polite request, the other is forcing your demands onto others and framing them in the moral wrong when they don't comply. There's a big difference between these two things.
Yes, it's true that you can't expect everyone to refrain from doing things that make you uncomfortable or to go out of their way to do a few extra things to help you. But, if someone asks politely about it, I see no reason to frame them as being in the wrong -- and there's nothing wrong with being a little considerate in return. If someone makes this kind of request and you don't go out of your way to please them then, well, I can't exactly blame you -- especially if you deem it an unreasonable request. But, doing the opposite of what they want just to spite them? Or telling them that they're in the wrong just for making such a request? I'm not sure that's really the right thing to do, either. In general, I think some basic respect and understanding goes a long way.
Interesting story: Recently, someone tried to join one of my RP's but with a CS filled with so many grammar and spelling mistakes that parts of it were legitimately difficult to understand. I told her that she'd need to proofread her CS and fix her grammar before it could be acceptable, and she told me that grammar and spelling is difficult for her because of her dyslexia. Now, there are two ways this could've gone but it didn't: I didn't tell her that her dyslexia wasn't an excuse, but I also didn't let her grammar issues slide just because of that. Instead, I understood that I can't expect her grammar/spelling to magically improve just because she can't use dyslexia as an excuse, as this is probably something that she does really struggle with, and I offered to help her fix her grammar, so that she could get to the point where her CS could be acceptable. If she hadn't been honest with me about her dyslexia, and instead just said "yeah ok I'll fix my grammar" while not actually fixing a lot of the mistakes, I would probably just think that she wasn't putting in the effort, and she might not have even gotten to join the RP. :/ At the same time, though, I couldn't have just let her poor grammar go through just because of her disorder -- because I need to be able to read CS's and IC posts.
I have no problem with people being honest with me about when their disorders make things difficult for them, and I would hope that no person legitimately struggling with a mental illness feels like they have to hide that sort of thing for fear of being called an attention whore. And, if someone is honest with me about that sort of thing, I might even be willing to lend a hand and help make things easier. But, it goes without saying that not everything can go your way just because you have a disorder. Explaining your actions can make people more understanding and it might make it possible to find a way to make things easier for you, if you're willing to at least try to meet people halfway. And you can't expect that everyone will conform to your own special set of needs, either. But, if people with mental disorders are just honest about what they need help with, and perhaps make some polite requests about how to make things easier for them -- and the people receiving those requests just try to be understanding and acknowledge that you can't expect someone with a mental disorder to not have any issues, well, I think that's a pretty solid way to make everyone happy. Again, basic manners and a little bit of openness and understanding goes a long way, I think.
Wow, this turned out really long. @_@ Sorry about that.
