read only a little of it. I found it to be pretty boring and I heard the english translations (I think tokyopop, the all around rapists of most things good in this world, picked it up) are pretty bad.
I read manga a lot but I'm not much into horror or psychological stuffs much, and my advice to you is to stop reading that immediately and go read something else that is a little less boring. Maybe it's your cup of tea, so if you are looking for a psychological, horror type manga to read, try death note or monster.