If you haven't read "The Raven", here's some necessary information you need to know in order to answer this question.
<span>As the speaker, or narrator, thinks about the situation, he starts to hallucinate about angels that appear and swing an “unseen censer.” They even start spreading perfume around the room. He connects the perfume to be something called Nepenthe. This is a mythical drink that works somewhat like an antidepressant. This causes him to cry aloud that nepenthe would help him forget about Lenore. The raven only replies "Nevermore" as it had always been replying before.
This proves that the <span>speaker's mental state shifts more and more toward madness.
The speaker’s mental state shifts more and more toward madness.
This is because as the poem closes, the word nevermore occurs in more and more depressing situations because it is the only word the raven can say, and the poet asks him questions to which that can be the only answer. These questions become maddening and more depressing as time goes by.
