The film looks to examine our own distorted points of view or detachments from reality. Like Patrick Bateman, we may be trapped craving the approval of others and denying ourselves the ability to distinguish fantasies from our reality. People are obsessed with how the others perceive them likewise in American Psycho Bateman achieves no catharsis, he's trapped in his own personal hell because he requires the recognition of the other yuppies to confirm his identity as a murderer. The irony is that Feynman's real crimes may as well be fantasy. The lack of acknowledging his reality drives Bateman further into madness and existential despair

It's about yuppie culture, the melding of identity, and the craving to stand out from a superficial homogenized society. Bateman's interpretation of the world is skewed by his inflated ego and his evident psychosis as well as presumably multiple mental illnesses. Bateman is a killer, but still, he's not the killer he thinks he is, as he goes insane he can't distinguish reality from fantasy. His over the top chainsaw massacre style killings may be an aestheticized elaboration on partial truths, ultimately the film doesn't care. The more significant point of the movies absurdity is that within his society Batemans not the psycho at all he's just one more normal guy amidst a horde of uncaring detached from reality, secretly discontented American psychos. Bateman is surrounded by like-minded superficial people obsessed with all the wrong things like making impossible reservations at Dorsia and the tasteful thickness of their business cards. Within the homogenized upper-class elite identities blur as everyone strives after a generic yet highly specific image of success.

Everyone we see in Bateman's company appears to be the same person. It's no wonder that identity is mistaken continuously and swapped throughout the film. The lawyer has mistaken Paul Allen or perhaps Batman has killed the wrong person becomes not only plausible but also an expression of the general confusion resulting from the loss of individual identity.

Meanwhile, although Batman tries like the rest to fit in, the emptiness of his lifestyle also fuels a craving to stand out. To escape the conformity that he on some level despises Batman leads a second life as a killer, where he's unfettered from the bounds of society. Although he actually wants to be seen as a murderer as someone different from the rest of society Bateman is denied even the satisfaction by every self-absorbed yuppie he meets. When he's seen stuffing a body into the trunk of a car, the witness is only interested in the bag.

This is a great movie. Look for the subtext under the dialogue.