any disturbing movie suggestions that isn't straight up gore?

most of these "disturbing movie iceberg"s are just straight up gore/porn videos after maybe tier 3. i need an actual movie with good plot that isn't tries everything possible to be disturbing (*coughs* human centipede *coughs*) but leaves you speechless using mostly phycological factors

edit: thank you everyone for the amazing suggestions! definitely gonna check out most of them :)