I assume this happens due to Stanley raping her and her sister Stella not believing her, tied with the fact that she liked Mitch but he wanted to have sex with her, after discovering the reason she came to Stella was that it was discovered that she had an affair with a high school student and then had multiple affairs with the people of her town when she was fired from her job. Now it poses a question, did Stanley raping Blanche cause her final decline to madness? I felt it was more along the lines of she already was having a descent into madness, that Stanley only sped that process up.
The final theme prevalent in “A Streetcar Named Desire” is class. Class is one of the main reasons the main character has so many issues. Her class issues most likely started a slow decline in mental health. Those issues where simply her losing her family estate and her family going bankrupt. Simply put, she lost everything she knew. She came from a high class social group, very prissy like. It is easily confirmable that the sudden shift in class and area had a profound effect on