New GM Need help with sanity

[Madnessinabottle]

I'm running a turn of the 19th century adventure. It's a little bit James Bond, Indiana Jones and a bit Cthulhu.
My question is how best to deal with sanity?
I Had three Idea;

1) Roll against Intelligence, Damaging effects apply to intelligence
This is like the knowledge is driving them insane.

2) Roll against Intelligence, then against HT.
More like what they have seen provides such a shock that it could actually cause heart attacks and seizures etc

3)Roll against Intelligence, Damage to FP
This would be that what they see is so damning to their reality that it actually drains their will to carry on and do things.

I had thought about giving Disads ( no points awarded) to the players, but it seems like a lot of work remembering that.

What does a more seasoned player think?