Duality of Blanche and O'Donnell

What do you think about the duality of both Blanche in 'A Streetcar Named Desire', and O'Donnell in 'Making History'? I'm referring to the twofold mannerisms of Blanche, for example in how she treats men, and how O'Donnell changes from a young, excitable and energetic character, to a deflated character.