Bauglir said:Making up a character that you know is doomed from the start seems to me like something of a pointless exercise, and not my idea of fun. YMMV ofc.
Make-believe role-playing games are a pointless exercise.
Moving right along, the CoC rules don't work well for D&D, even with the 'hardening' patch.
Take a look at the Unknown Armies system. There are five insanity stresses: violence, unnatural, isolation, helplessness, and self. These stresses occur on a scale of 1-10. When you suffer one of them, you make what amounts to a save; fail and you get a little closer to crazy, succeed and you get a little closer to becoming a hardened psychopath.
What's great about this system is that it's perfectly scalable: applying it to D&D, you can just decide what counts as low, moderate, or high stress. Slap the value onto a DC10 (or 15 or 20 or whatever floats your boat) Will save and decide how many failures and successes before you become nuts.
So a level 8 helplessness stress (trapped by the imprisonment spell or something) might call for a WDC18 save.
If the character has already failed nine (or five or fifteen; again, whatever) such saves, he develops a disorder.
If the character has already succeeded at nine (etc.), he develops a very different disorder (best manifested as the loss of some kind of passion).
In short, I vote for the other UA!