The Black Cat and The Fall of the House of Usher are two very different yet parallel stories. For example, though the stories are different, Poe uses very similar themes for both of them. One theme is Passion. In both the stories, one of the main characters has had a passion for something or the other- The Black Cat: the narrator’s passion for animals and in The Fall of the House of Usher: Roderick Usher’s passion for music and the arts. Poe shows that passion can be expressed in many ways, no matter what state of mind the person is in. Perhaps this could be an indirect reference to himself, how, though he was an opium addict, he had a passion for writing and the opium did not stop him from expressing it.
Another common theme between the two stories is struggle- trying to get out of a situation when you just cannot. In The Black Cat, the narrator tries to escape from the guilt of killing Pluto, but cannot, so he ends up killing his wife. He could not do anything to stop himself from behaving the way he did. This is extremely similar to The Fall of the House of Usher where Roderick Usher is trying to escape from the mental illness that he has. Asking his childhood friend to visit, he had hoped that it could help bring him out of his shell, maybe just miraculously cure him, but it does not. In the end, just like the narrator in The Black Cat, he ends up loosing something extremely precious- his life. Poe also uses Single Unifying Effect in both stories. Five examples of him using it in The Black Cat are: The voice from the tomb (the scream); the death of Pluto, his first cat; the ruining of his house; the murder of his wife and the image of the Gallows.