Most games are about having fun and escaping from the real world, so even if gruesome elements are present, like in horror games, players make sure it's "only a game". Sometimes subjects are approached in a tounge-in-cheek or pulp manner, e.g. Nazism. But a distance is always kept. Is it possible to tackle a serious issue, such as child abuse, rape, mass murder, insanity, illness, religion in a role-playing game?
Of course, obviously, it all depends on the mindset of the given players. They have to know each other to a certain extent, because you wouldn't start telling stories about children getting raped to an almost stranger on a convention. Also, somebody might be personally offended by certain themes.
I have some experience playing games like Kult, which encourage introducing dark and awful themes and build games around them, but sometimes these games (due to the release in the 90's, maybe) are over-the-top. I'm not talking about gore or brutality for brutality's sake.
What's your take? I know I'm answering my own question here ("it all depends on the players"), but I'd be really interested in actual examples. Any experiences running serious games? Lots of games opt for deep psychological explorations, but how many players are actually ready to do that?