re: American Psycho (2000) SPOILERS

There's a debate as to whether or not it was mostly in his head (that's what I think) or that, since all of the Wall Street guys have become so similar in an effort to fit in, that the lawyer simply can't really tell the difference between Paul Allen and others of his ilk (see Paul Allen himself thinking that Bateman was another guy the entire movie), which is a pretty legit theory itself and more interesting than the typical "in the head" deal. I think it was imagined because some of the scenes were too out there(running naked through hallways with a chainsaw and having no one else see him, the massive killing spree) plus Paul Allen's apartment being shown to potential buyers with no sign of murder).