Bret Easton Ellis uses a number of stylistic techniques to render Patrick Bateman's distinctive voice in American Psycho. The most easily identifiable of these is Patrick's idiosyncratic practice of listing the brand of each and every article of clothing and consumer item that he recognizes.
These lists almost always come immediately after a character arrives in a scene; here, for instance, Patrick sees Courtney for the first time in the novel: "Courtney opens the door and she’s wearing a Krizia cream silk blouse, a Krizia rust tweed skirt and silk-satin d’Orsay pumps from Manolo Blahnik." (Krizia, a real brand whose cheapest items today cost more than a thousand euros, is very popular among the women in Patrick's circle.) The list of clothing items form a kind of epithet for the characters, establishing their position and status in Patrick's eyes. Throughout the book, whenever Patrick is sane and coherent, he recites these lists without fail. This repetitive style constantly reiterates Patrick's neurotic, luxury-obsessed outlook while also creating a detailed and specific backdrop for the novel's action.
Ellis's prose adapts to depict a wide variety of Patrick's mental experiences. As Patrick descends into emotional suffering or violent compulsions, the first-person narration twists to fit his state of mind. For instance, in the chapter "Killing Child at Zoo," Patrick's drugged stupor manifests in a slow-moving, opaque story of him bumbling through the various zoo exhibits: "A crocodile floats morosely in an oily makeshift pond. The puffins stare sadly from their glass cage." Then, when Patrick has a sudden moment of fury, the text adapts forcefully in turn: "my sudden lack of care crests in a massive wave of fury and I pull the knife out of my pocket and I stab him, quickly, in the neck." The text becomes direct and staccato when Patrick becomes murderously focused, and becomes woozy and incoherent when Patrick is drugged or hallucinating. Ellis uses this style to make Patrick's mental state seem faithful and real.