I agree with this post. I don't even speak freely about my run-ins with mental health, and yet I feel like some of these people who create these insane, evil characters discuss it way too much, whether in RP or out of character. At this point, I consider it a warning sign of someone who has stereotyped mental illnesses. I believe it to be a harmful thing, because at some point impressionable people are exposed to characters like this, and they end up with this mindset that mentally ill people are violent and/or aggressive. Now, in FH, it seems like an epidemic. Having a mental illness doesn't even make a character evil, as I suspect these kinds of people believe. They just want an evil character. It's possible to have an evil character who isn't mentally ill.
However, I don't want to discourage anyone from having genuinely thought-out characters with accurate portrayal of mental health issues. In fact, I'd support that. Anyone who asks me about my problems in a decent way, because they're curious or for research purposes, will get an answer. My idea is to guide someone who is stereotyping towards a better solution - understanding why the character is the way they are, what contributed to their illness (genetic or environmental), and the more accurate reactions to stimuli.
This is a very interesting post, one which I agree with quite a bit. Thank you for sharing it.