describe madeleine usher and the symptoms of her illness. how does she seem to interact with roderick and the narrator

Before the narrator gets to the house, Madeline has fallen into a catatonic state.We really have to question if Madeline actually existed. Madeline can be seen as kind of like a doppelganger of Roderick: kind of like Norman Bates and his mother in the movie Psycho. Perhaps Madeline's return from the dead is only a metaphor of Roderick's fears. In any case, Madeline serves as a plot device to give a manifestation to Roderick's fears and anxieties.