Both Edgar Allan Poe stories “The Tell-Tale Heart” and “The Cask of Amontillado” are told in the first-person and both feature individuals with definite mental health issues, of which drove them to commit murder. In the case of “The Tell-Tale Heart,” the unnamed narrator makes a point early-on of professing his sanity (“You fancy me mad. Madmen know nothing. But you should have seen me”), while concurrently demonstrating that he is indeed mentally ill. The narrator of “The Cask of Amontillado,” in contrast, is not particularly concerned with questions of mental stability, but his actions definitely bespeak an individual who has problems coping with what he considers an adverse situation: The repeated insults he perceives he has suffered at the hands of his tormentor, Fortunato, have driven him to commit murder (“The thousand injuries of Fortunato I had borne as I best could, but when he ventured upon insult, I vowed revenge”). What both stories, then, have in common is a main protagonist who meticulously plans on murder, albeit for entirely different reasons. One commits murder because he has been driven insane (or, was already insane but reached a tipping point), while the other commits murder to avenge slights he believes he has received at the hands of another.
These are the main parallels between “The Tell-Tale Heart” and “The Cask of Amontillado.” Both protagonists plan and carry out a murder. Both stories are told by the individuals carrying out the murder. Where the two stories differ is in motive (the need to eliminate the old man and his vulture-like eye versus revenge for a history of insults) and in outcome. We know that the protagonist in “The Tell-Tale Heart” is caught by the police because he is convinced in the presence of the police that he hears his victim’s beating heart beneath the floorboards. We have no reason to believe that the protagonist in “The Cask of Amontillado” is ever suspected of a crime, as he concludes his narration by declaring that “for the half of a century” following the murder “no mortal has disturbed” his handiwork (i.e., the masonry concealing the remains of his victim). One can surmise that the narrator/murderer in “The Tell-Tale Heart” was driven by guilt to confess his sin; Montresor, the narrator/murderer in “The Task of Amontillado,” felt no such remorse.