Can anyone please...

i'm still largely unfinished and has just began with this part of my list but it's basically the type of the characters you are looking for (the mangas in this page ) http://www.mangago.me/home/mangalist/69274/?filter=&page=5

http://www.mangago.me/home/mangalist/57857/
I have mentioned the ones that have psychotic twisted characters in them, in my review notes. But I would recommend you picking up ANYTHING by Harada sensei. She'e the QUEEN when it comes to portraying psycho/sick characters. For starters try this one -
http://www.mangago.me/read-manga/gintama_dj_mienai_kusari/

http://www.mangago.me/home/mangatopic/1107916/