Who Is The 'American Psycho'?

The American Psycho is a fictitious character called Patrick Bateman.  He is the lead character in the book American Psycho, which was written by Bret Easton Ellis and published in 1991, later to be made into a film of the same name.
American Psycho caused a huge outcry when it was first published.  It contains graphic scenes of torture, both sexual and physical.  The sheer volume of violence contained within the book also created great controversy.  Bateman is a serial murderer by night: and by day he is a star on Wall Street.  
Ellis describes the work as a black comedy.  It is incredibly dark as a work of fiction.  However, some of its defenders feel that it points out the hypocrisy of modern living and how Bateman's obsession with status and material wealth showed that he had closed off from his feelings, thus enabling him to take life without any remorse or regret.