Is there a good adaptation of Call of Cthulhu's Sanity rules to the Storytelling system of the new World of Darkness (possibly replacing Morality)?
(Edited the title to make it more precise.)
The "Forbidden Lore" system from World of Darkness: Mirrors (p.28-32) is cognate to the Sanity system; characters garner Insanity points and lose rating in their Reason score. Along the way, they acquire Mental and Social penalties and gain bonuses to Occult endeavors — including the ability to use supernatural powers without gaining the associated template. The correspondences seem fairly close.
To my mind, CoC Sanity rules are quite easy to use as is. For instance you can use the
sum of the
mental characteristics as a base and multiply by 5 or 6 (depending on how crazy your world is) to get the starting
sanity and then use the typical CoC Sanity rules.
I think something like that may work.
Personally I'd have a look at Unknown Armies mechanics, which to me look more nuanced (and I believe can be retooled for different game systems, too).
The integrity rules from the God-Machine Chronicle Rules Update could be a good substitute for CoC sanity.
Unlike the previous morality system that is based purely on sins (which the developers for GMC often refer to as a Victorian concept) , this system is based on breaking points, and seeing cosmic horrors is a perfect example of that.
If you fail (and you can choose to fail dramatically) you can suffer a Condition (also in the GMCRU) that represents your sanity/integrity suffering.