Homelessness
Ellis's vision of New York City is seemingly populated only by the extravagantly wealthy on the one hand, and the homeless on the other. Patrick and his colleagues routinely disparage and torment the homeless people they see on the streets, and Patrick himself murders one homeless man and his dog. Timothy Price disparages the notion of social welfare in the opening chapter, and the novel's amoral characters seem to view homelessness itself as a kind of moral failing. Although Patrick and others are fans of Les Miserables—a story about the struggles of the downtrodden—they ignore its social message.
High fashion
Ellis's prose exhaustively inventories the designer labels of each article of clothing that each character wears, emphasizing the role that high fashion plays as a status symbol in the elite world of finance. Patrick judges the people around him according to the sophistication of their wardrobe, reducing everyone to an assemblage of luxury commodities. Patrick openly resents sloppy dressers, like Stash and Luis, and becomes overwhelmed with jealousy when he sees someone dressed better than he is, like Paul Owen.
Ultra-violence
Patrick is not merely violent but ultra-violent, taking pleasure in the slow, ritualistic torture and mutilation of his victims. Patrick is highly attentive to the grotesque details of disfigured bodies, and takes exceedingly great care to maim and dismember them, in part to overcome the degree to which he has become desensitized to the world around him. Patrick's ultra-violent fantasies are implied to be imagined, and to be a result of his pathological hatred of anyone who does not conform to his restrictive worldview.
Fine dining
Patrick and his colleagues constantly move through a rotation of exclusive restaurants, and seem to take no decision more seriously than deciding where to eat. Names of the restaurants—like "Nowhere" and "Vanities"—are often highly symbolic, suggesting that they may only exist in Patrick's mind. Dorsia, the supremely exclusive restaurant of Patrick's dreams, is twice the setting for humiliating events, first when he is forced to wait for his brother, and then when he and Jean are forced to leave. Ellis satirically juxtaposes decadent descriptions of gourmet food alongside Patrick's descent into foul acts of cannibalism.
Impostors
Impostors abound in American Pyscho, through both careful planning and happenstance. Patrick maintains the illusion that he is Marcus Halberstam—and that his girlfriend Evelyn is Marcus's girlfriend Cecilia—when he is around Paul Owen. Patrick's reputation as the "the boy next door" is undermined by the ultra-violent, pathological fantasies that he acts out. Patrick tells Bethany that he only works on Wall Street so that he can "fit in," suggesting that he feels like an impostor even in the world he feels most comfortable. Characters in the novel constantly mistake each other for other people, seemingly reducing identity to a process of impersonation.
