ff
Skim thru these? http://www.mangago.me/home/mangalist/217229/
And anything by Harada? Like Color Recipe etc, I mean it's a frequent answer but she really is a queen. Also try Ogawa Chise!
Also I heard of the manhwa Warehouse? it's pretty psychological but I haven't started on it yet.
-Girl who can see disturbing ghost. (short but good)
http://www.mangago.me/read-manga/girl_that_can_see_it/
-Zombie Apocalypse with the touch of really REALLY disturbing horror. Please don't read it at night (or please do if you really want to have nightmare, make sure you're alone.)
http://www.mangago.me/read-manga/sweet_home/
I'll post if more I found more about this (=・ω・=)
BEST psychological, twisted or fucked up yaoi stories you can recommend!!! That stuck to your head for a while, you even dream or let you stop reading yaoi for a while. Its fine even if it is not here in mangago as long as you provide the title or the link
THANK!