Gaslight - 1940 creepy

Story of someone who should be loving someone but trying to make them go crazy. I once thought these kinds of movies were just weird entertainment, but more recently I've been looking at old films like "Whatever happened to Baby Jane" because actually filmakers often are trying to get a message across. These strange stories are the stories of how people in the west can become extremely unwell. To clear up confusion between this and the one only four years later, this is the British film. Another film that is similar is "Rebecca" from the book by Daphne Du Maurier and directed by Hitchcock.