Christian Bale insisted on getting "American Psycho" author Bret Easton Ellis' approval for his portrayal before the start of his work on the 2000 film, and arranged a meeting. Bale showed up to the meeting dressed and groomed as Bateman, even introducing himself as "Patrick Bateman." After 10 minutes, Easton Ellis begged Bale to stop because his hands were shaking and he could not take it anymore. Easton Ellis has said this was the single creepiest moment of his life.
After the novel was originally optioned in 1991, Ellis himself was set to write the script for director Stuart Gordon with Johnny Depp starring as Patrick Bateman. Gordon wanted to do the film in black and white, and stick as close to the book as possible, meaning a guaranteed X-rating. After the project fell through, David Cronenberg replaced Gordon, with Brad Pitt set to star. This project also failed to get off the ground. Based on Ellis, Cronenberg hated the restaurant and nightclub scenes, and didn't want to shoot the violence. When Ellis basically ignored these requests, a disappointed Cronenberg hired his own writer, and when that didn't work out either, he left the project.
Eventual director Mary Harron had attempted to read the novel when it was originally published, but found it too violent. She told producer Edward Pressman that she would join the project only if she could write her own screenplay. Pressman commented that out of all the directors who attached themselves to "American Psycho," Harron was "the only person who actually ever conveyed a clear solution as to how to do it." Harron recruited Guinevere Turner, who she had been working with on what would become "The Notorious Bettie Page" (2005), to co-write. Turner was not a horror fan and had never heard of "American Psycho," but Harron convinced her that it would be a good project to pursue. Though she found the novel unsavory, Turner appreciated its blend of humor and horror and concluded that "with the right spin, it could be a really subversive, feminist movie."
Ellis reportedly based the character of Patrick Bateman off of his own father.