Possessed

This movie has nothing to do with the 1931 version that also Joan Crawford. It's more along the lines of The Snake Pit. It stars out with Joan Crawford walking the streets in a trance-like state and she keeps on repeating the name David. She's sent to the mental ward at the hospital and the movie goes in flashback to show how she ended up like this. The flashback stars with Joan Crawford wanting to marry Van Heflin but he just wants to break the relationship off. She never gets over it and goes to work as a nurse taking care of Raymond Massey's wife. Pretty soon, they find his wife's body in the lake but they don't know if it was an accident or suicide. Raymond Massey asks Crawford to marry him but she's still in love with Heflin, who is working with Massey. She agrees but Massey's daughter doesn't like her and she slowly stars to go insane. I guess this is one of the first movies that deals with mental illness.