Talking about DISTURBING sort of material, then i would like to suggest some korean movies which i have seen:
*Thirst [ disturbing, dark, violent, and i have found this one quite romantic(lol), unique in its own way. might leave you thinking for days]
*My wife got married [ plz don't expect anything from conclusion bcoz it may leave u disappointed, just watch this movie u will not be able to leave this movie in between may be because actors did there part really well. Going by it's rating i think is pointless as it's "disturbing" so people will definitely have split emotions. If u r a Football Fan and on top of it if u r a Real or Barca fan, then i swear it's icing on the cake for u. ]
Moebius , Vengeance trilogy or any other kim ki duk or park chan wook directed movie which usually everyone knows.
"Hope" should not be mentioned in this section as its much much more than just a disturbing movie.