"The Black Cat" like many of Poe's stories has a couple of autobiographical elements.
1. First, the death of a cherished woman occurs. Poe often includes this type of event in his writing because his mother--a beautiful actress--died when he was young. Later Poe loses his young wife to consumption and writes more works that include a woman's death. In "Cat," the narrator seems to love his young wife, but ultimately turns against her when she tries to stop him from killing the offending cat.
2. Secondly, the narrator is an alcoholic. Poe established a reputation as an alcoholic and was even last seen alive at a tavern. In the story, the narrator mentions that there is no disease worse than alcohol, and readers can infer that perhaps Poe was commenting on his own addition and how it changed him from who he had always wanted to be into someone who could not control his actions or future.
3. Thirdly, the narrator is unreliable and illogical. While Poe did not see himself as maniacal (as many of his characters are), he did recognize in himself and in others the potential to dwell on the dark themes of life and that that type of thinking can skew one's view of events and people.