What are some themes in the poem "The Raven" by Edgar Allan Poe?

In "The Raven," Edgar Allan Poe employs a Gothic ambiance to explore themes of grief, negativity, and depression. As the poem opens, the narrator is at home alone at night feeling sad and lonely. He is reading to try to forget about his "sorrow for the lost Lenore." His lost loved one so fills his thoughts that at various times in the poem he believes she is near him, perhaps in the form of a spirit, ghost, or angel. That is why the rustling of the curtains and the mysterious knocking "thrilled me—filled me with fantastic terrors never felt before." Later he thinks he hears her footsteps and smells her perfume. His grief is affecting his mind, and thoughts of his departed loved one overtake him so that he imagines her presence. This theme portrays how grief dominates the mind of one who has recently lost a loved one to the extent that his imagination can get carried away.

Sadly, the man's grief leads to negativity and doubt. Although he allows the bird to entertain him for a short while, he soon succumbs to doubts about whether he will see Lenore again in the afterlife and whether he will ever be able to "forget" her in this life and heal from the pain of his intense grief. This leads him to ask the wrong questions of the bird. Knowing the bird is only capable of saying a single word and that "what it utters is its only stock and store," the narrator nevertheless asks a question that is sure to bring an answer of despair. This points out that when one asks the wrong question, one gets the wrong answer. Ironically, a person who is swathed in negativity only asks negative questions that confirm the despair he feels. 

Finally, depression is a major topic of the poem. As the man sinks further into grief and negativity, he finds himself drowning is a disabling sea of depression. The bird's beak in his heart, its eyes demonically gleaming at him, and its shadow enveloping him are symbolic of the depression that immobilizes him and makes him believe that he will feel that way forever. In this way, the poem suggests that grief and negativity can produce long-term depression in a person who has lost a loved one and is experiencing extreme loneliness.