Throughout the story, Roderick Usher’s mental disorder progresses from a strange nervous agitation to all-out madness. How does Usher’s worsening mental stateaffect events in the story, or drive the plot?

Usher's mental state and deteriorating faculties explain his reactions.... support the thickening of the plot and illustrate his ensuing madness. As the story progresses it gets crazier and more difficult to understand, Usher's madness directly connects to th plotline.