[@Buddha]So to clarify, you're interested in discussing genuine mental illnesses? I am not sure how that alone can be considered a question. But I think(?) I have a better grasp on the second part of the topic that you wish to discuss, which is how something like rolplaying would affect someone with a mental disorder. 

I think this is a notable concern as almost anyone with a mental disorder seems to have something they obsess over. Obsessions are dangerous, but I'm not sure what the harm in escapism is. It could hinder their ability to heal, even reduce their effectiveness as a member of society. But I'd rather them be saving a make believe kingdom than subscribing to someone's blog on Facebook or even 4 Chan. At least on RPG the escapism is contained to a written story that everyone else more or less knows is a farce. The OOC constantly reminds you of this. But when you use facebook, dressing up, or going to expensive parties that you really can't afford as a form of escapism, I think they're doing far more damage to themselves. They are escaping in plain sight, with real people.

I think there are worse things a mentally ill person could do with their free time.