http://www.mangago.me/read-manga/to_the_sea/
not sure if he is a seme....
http://www.mangago.me/read-manga/itou_san_kuraka_sui/
main story and side story. Not sure if its exactly what disorders they have
http://www.mangago.me/read-manga/shiiku_gakari_rika/
tetsu qualifies i think.....
http://www.mangago.me/read-manga/dog_style/
Not mc, but a guy in the mc past, seems to qualyfy
http://www.mangago.me/read-manga/horo_horo_to/
side story, he seems like one to me
http://www.mangago.me/read-manga/boys_next_door/
You might also find few more here - http://www.mangago.me/home/mangalist/57857/
http://www.mangago.me/read-manga/shoshitsu_dj_d_no_satsujinsha/
http://www.mangago.me/read-manga/nise_x_koi_boyfriend/bt/285985/Ch5/1/ He may not be a psychopath, but he's extremely possessive & he's good at psychological manipulation
any yaoi with a psychopath seme?