The story is told in the first-person by Patrick Bateman, a wealthy, narcissistic, and vain Manhattan investment banker who lives a double life as a serial killer.

Alison Kelly of The Observer notes that while "some countries [deem it] so potentially disturbing that it can only be sold shrink-wrapped", "critics rave about it" and "academics revel in its transgressive and postmodern qualities".

"[7] Set in Manhattan during the Wall Street boom of the late 1980s, American Psycho follows the life of wealthy, young investment banker named Patrick Bateman.

Bateman, in his mid-20s when the story begins, narrates his everyday activities, from his recreational life among the Wall Street elite of New York to his forays into murder by night.

Through present tense stream-of-consciousness narrative, Bateman describes his daily life, ranging from a series of Friday nights spent at nightclubs with his colleagues—where they snort cocaine, critique fellow club-goers' clothing, trade fashion advice, and question one another on proper etiquette—to his loveless engagement to fellow yuppie Evelyn and his contentious relationship with his brother and senile mother.

Bateman's stream of consciousness is occasionally broken up by chapters in which he directly addresses the reader in order to critique the work of 1980s pop music artists.

His murders become increasingly sadistic and complex, progressing from simple stabbings to drawn-out sequences of rape, torture, mutilation, cannibalism, and necrophilia, and his grasp on sanity begins to slip.

These incidents culminate in a shooting spree during which he kills several random people in the street, resulting in a SWAT team being dispatched in a helicopter.

This narrative episode sees the first-person perspective shift to third-person and the subsequent events are, although not for the first time in the novel, described in terms pertaining to cinematic portrayal.

Later, Bateman revisits Paul Owen's apartment, where he had earlier killed and mutilated two prostitutes, carrying a surgical mask in anticipation of the decomposing bodies he expects to encounter.

The real estate agent, who sees his surgical mask, fools him into stating he was attending the apartment viewing because he "saw an ad in the Times" when, in fact, there was no such advertisement.

Bateman's mental state continues to deteriorate and he begins to experience bizarre hallucinations such as seeing a Cheerio interviewed on a talk show, being stalked by an anthropomorphic park bench, and finding a bone in his Dove Bar.

At the end of the story, Bateman confronts Carnes about the message he left on his machine, only to find the attorney amused at what he considers a hilarious joke.

In the dialogue-laden climax, Carnes stands up to a defiant Bateman and tells him his claim of having murdered Owen is impossible, because he had dinner with him twice in London just a few days previously.

This leads Patrick Bateman to act as if "everything is a commodity, including people",[9] an attitude that is further evident in the rampant objectification and brutalization of women that occurs in the novel.

[12] Bateman's episodes of schizophrenia also shows clear signs on how he copes with being an affluent person living in a superficial world, fashioned on consumerism.

[14] On the one hand is a rich Wall Street banker, Bateman, concerned and very self-conscious about every detail of his physical appearance, expensive possessions, and control of the people and the world around him.

On the other hand, is the inner self of Patrick Bateman, the aboriginal-self, who copes and relinquishes his outer complications and "fake" identity, created by consumerism, through violence on other human beings, who he finds consumable, and expresses absolute control of his desires and true self through his violent fantasies.

Serpell brings to light the patterns and trends Ellis expresses through Bateman, the consequences of how "serialized consumer exchanges in an economy where commodities and bodies become interchangeable and indistinguishable",[15] could affect society, and the way affluent people view others whether they are higher, lower, or the same in wealth or social status.

[16] Bateman's character and traits, according to Heise, challenge what readers understand as the social norms for the way the elite upper class think and react to society on a normal basis.

He continues:[17] The novel subtly and relentlessly undercuts its own authority, and because Bateman, unlike, say, Nabokov's unreliable narrators, does not hint at a "truth" beyond his own delusions, American Psycho becomes a wonderfully unstable account.

The most persuasive details are combined with unlikely incidents until we're not only unsure what's real, we begin to doubt the existence of reality itself.It has often been noted that Patrick Bateman is an example of an unreliable narrator, and this feature of American Psycho has been the subject of discussion in several academic works.

[25] Writing for The New York Times, Roger Rosenblatt quipped, "'American Psycho' is the journal Dorian Gray would have written had he been a high school sophomore.

[37] During the Duke lacrosse case, a team member named Ryan McFayden sent a profane email to several of his teammates alleging he was going to kill and skin some strippers.

[41] The Motion Picture Association of America (MPAA) gave the film an NC-17 rating for a scene featuring Bateman having a threesome with two sex workers.

[43] Upon its theatrical release, however, the film received positive reviews in crucial publications, including The New York Times which called it a "mean and lean horror comedy classic".