Will wonders never cease! I finally found an S/J fic with a definitely sociopathic Sherlock that I thoroughly enjoyed. It's creepy in a good way.
Stolen Moments. Not terribly surprisingly, it's by
velvet_mace, the same author whose
Collared WIP is an amazing helping of fucked-up angst, with forced-to-be-cruel!Sherlock and probably-going-to-be-broken!John, both at the mercy of utter-bastard!Mycroft. (And if you like that one, while it's currently up to Chapter 3 on
velvet_mace's LJ, there's a lot more in first draft form on the kink meme; follow the link labeled "Prompt" in the intro to Chapter 1.)
But back to Stolen Moments. It's in Sherlock's POV, and I don't think I'm spoiling anything if I say it involves hypnosis!rape. I am tempted to call it a 5 on the Sociopathy Scale, but I think that's due to my bias toward awarding 6's only to fics I don't like. Certainly this Sherlock has zero conscience, feeling regrets only for the possibility that he's basically broken his toy. And he does need to construct external constraints in order to change his behavior; he's not able to do so via willpower alone. So I'll go ahead and give it a 6.
Enjoy!