This is the most frequently asked question in relation to the film, and the answer remains ambiguous. As with the questions of why Allen's apartment is empty, how did Carnes see Allen in London, and why people ignore Bateman's outbursts, there are two basic theories:
1) the murders are very real and Bateman is simply being ignored when he tries to confess
2) everything happened in his imagination
Much of the discussion regarding the possibility of everything being in his mind focuses on the sequence which begins when the ATM asks him to feed it a stray cat. From this point up to the moment he rings Carnes and leaves his confession on the answering machine, there is a question regarding the reality of the film; is what we are seeing really happening, or is it purely the product of a disturbed mind? An important aspect of this question is Bateman's destruction of the police car, which explodes after he fires a single shot, causing even himself to look incredulously at his gun; many argue that this incident proves that what is happening is not real, and therefore, nothing that has gone before can be verified as being real either. Of this sequence, Mary Harron comments "You should not trust anything that you see. Trying to feed the cat into the ATM is sort of a giveaway. The ATM speaking to Bateman certainly indicates that things have taken a more hallucinatory turn." As such, if this scene is an hallucination, the question must be are all of his murders hallucinatory? Interestingly enough, in the corresponding scene in the novel, the narrative switches from 1st person present to 3rd person present mid-sentence (341) at the beginning of the sequence, and then back to 1st person present (again mid-sentence) at the end (352). This is a highly unusual narrative technique, suggestive of a sizable sift in consciousness and focalization, and an altogether different narrative perspective. This lends credence to the theory that the entire sequence is a hallucination, which in turn lends credence to the suggestion that much of what we see in the film is also an hallucination.
However, if this is the case, and if this sequence does represent pure fantasy, Harron ultimately felt that she had gone too far with the hallucinatory approach. In an interview with Charlie Rose, she stated that she felt she had failed with the end of the film because she led audiences to believe the murders were only in his imagination, which was not what she wanted. Instead, she wanted ambiguity; "One thing I think is a failure on my part is people keep coming out of the film thinking that its all a dream, and I never intended that. All I wanted was to be ambiguous in the way that the book was. I think it's a failure of mine in the final scene because I just got the emphasis wrong. I should have left it more open ended. It makes it look like it was all in his head, and as far as I'm concerned, it's not" (the complete interview can be found here).
Guinevere Turner agrees with Harron on this point; "It's ambiguous in the novel whether or not it's real, or how much of it is real, and we decided, right off the bat, first conversation about the book, that we hate movies, books, stories that ended and 'it was all a dream' or 'it was all in his head'. Like Boxing Helena, there's just a lot of stuff like that. [...] And so we really set out, and we failed, and we've acknowledged this to each other, we really set out to make it really clear that he was really killing these people, that this was really happening. What's funny is that I've had endless conversations with people who know that I wrote this script saying "So, me and my friends were arguing, cause I know it was all a dream", or "I know it really happened". And I always tell them, in our minds it really happened. What starts to happen as the movie progresses is that what you're seeing is what's going on in his head. So when he shoots a car and it explodes, even he for a second is like "Huh?" because even he is starting to believe that his perception of reality cannot be right. As he goes more crazy, what you actually see becomes more distorted and harder to figure out, but it's meant to be that he is really killing all these people, it's just that he's probably not as nicely dressed, it probably didn't go as smoothly as he is perceiving it to go, the hookers probably weren't as hot etc etc etc It's just Bateman's fantasy world. And I've turned to Mary many times and said "We've failed, we didn't write the script that we intended to write"."
In line with what both Harron and Turner feel about the question of whether or not the murders are real, Bret Easton Ellis has pointed out that if none of the murders actually happened, the entire point of the novel would be rendered moot. As with the practical theories regarding the Carnes conversation, the outbursts and the empty apartment, interpreting the murders as real is part of the film's social satire. Ellis has stated that the novel was intended to satirize the shallow, impersonal mindset of yuppie America in the late 1980s, and part of this critique is that even when a cold blooded serial killer confesses, no one cares, no one listens and no one believes. The fact that Bateman is never caught and that no one believes his confession just reinforces the shallowness, self-absorption, and lack of morality that they all have. None of them care that he has just confessed to being a serial killer because it just doesn't matter; they have more important things to worry about. In Bateman's superficial high-class society, the fact that even his open confession to multiple murders is ignored serves to reinforce the idea of a vacuous, self-obsessed, materialistic world where empathy has been replaced by apathy. By extension then, this could be read as a condemnation of corporations in general; they too tend get away with murder (in a figurative sense) and most people just choose to ignore it, just as do Bateman's associates. In this sense then, Bateman serves as a metaphor, as do the very real murders. If the murders were purely in his head, the strong social commentary would be rendered mute and the film would become a psychological study of a deranged mind rather than a social satire. And whilst that is a perfectly valid interpretation, as Harron indicates above, it is not entirely what the filmmakers were attempting to achieve.
