Which detail effectively creates an atmosphere of decay?

What is the problem with the following sentence: cameron, who has an extreme and unreasonable suspicion of other people and their motives, suffers from paranoia which is a psychological disorder characterized by delusions of persecution or grandeur, was absolutely sure that someone was following him even though he was absolutely alone and hadn't seen a car for miles and miles.

(the black cat poem) where does the writer fail to support her points with evidence? what evidence from the story would you suggest adding to support these points?

When mrs. jameson says "it (the desert) won't leave you cold," what does she mean?