Ambiguous Disorder: Seems to have Borderline Personality Disorder (in addition to his narcissism, sadism, and sociopathy), as this would explain his hallucinations as well as some other things he reports, such as identity disturbance, his mood swings, and his tendency to not feel much of anything.
Asshole Victim: He finally receives his comeuppance in the novel Lunar Park when he gets trapped in a pier fire. He really had it coming to say the least.
Attention Whore: Confesses his crimes near the end because he wants people to know him and because he wants to matter! It doesn't work as no one believes him and his crimes may have been all just a fantasy. In the end, no one will give a shit about him, no matter how hard he tries.
Deadpan Snarker: Makes several snarky comments at the people around him, when he isn't thinking about killing them, that is.
Even Evil Has Standards: Of all the horrendous atrocities he's committed, including murder, cannibalism, and so on, Bateman draws the line at anti-Semitic remarks. Or seems to. (In the book he has an argument in a Jewish deli and insults the people running it.)
Evil Is Petty: Almost all of his murders are motivated by people having nicer clothes or better apartments than he does.
Fate Worse Than Death: Trapped in a shallow world of greed and hatred than he despises as much as he detests himself. All while knowing that nothing he does will ever be of any consequence.
For the Evulz: If it isn't his primary motivation, it comes damn close. He kills a child and is only upset because it wasn't evil enough for his taste.
Hallucinations: Caused by stress, and extremely bizarre, but he believes every one of them.
Inferiority Superiority Complex: Despite his insane levels of narcissism, it is shown often that Bateman utterly detests himself as much as he does everyone else and most of his murders are motivated by people unintentionally reminding him of this.
It's All About Me: The only people he refuses to kill are ones who profess some affection for him, all of which he coldly discards.
Pop-Cultured Badass: Deconstructed. He tries to define himself through his appreciation for music, art, and pop culture and relates this much to the reader/audience, but his grasp and understanding of his favorite music and artists is reduced to what material they make the most appealing to the widest audiences and lowest common denominator, such as dismissing early Genesis albums with Peter Gabriel (and his "lame solo career") as being "too artsy, too intellectual" and favoring the more commercially-driven direction of the group after Phil Collins became the group's frontman. Other assessments he makes of popular singers and bands are frequently off-the-mark and factually wrong, like being convinced that Whitney Houston is a jazz singer or believing "You Can't Always GetWhat You Want" is a song by The Beatles. Elsewhere, he often speaks of owning what's described as the original version of "Sunrise with Broken Plates"◊ by artist David Onica (while discreetly boasting of the high cost he paid to obtain it), only for his ex-girlfriend to point out to him that he hung it upside down. All of this only serves to further demonstrate Patrick's shallowness and delusions about having "good taste."
Purely Aesthetic Glasses: He seems to just wear them because they are designer and because all his other Yuppie friends wear the same thing.
Psychopathic Manchild: A very subtle case, but his demeanour behind his Mask of Sanity is rife with this, with things like murdering people over having better stuff than he has and desperately trying to garner attention for himself make him come off as a petulant brat having frequent tantrums because no one's paying attention to him.
Sadist: Gets off on causing pain. But Patrick knows even if he's doing something like that, it'll never bring any consequences. EVER.
The Sociopath: Informs everything about his life — the film's director describes him as a Martian trying to imitate human behavior (and never quite hitting the mark). He is probably one of the best examples in media.
Straw Hypocrite: He often espouses lofty political ideals in public like taking care of the poor or fighting discrimination and sexism. Bateman himself knows he's just bullshitting to hide his true nature, as privately he not only holds numerous racist, elitist, and sexist views, but he's also a psychotic murderer who frequently kills women, minorities, and homeless people.
Tall, Dark, and Handsome: As we learn during his narration of his morning routine, he is the pinnacle of physical perfection.
Villain Protagonist: A Serial Killer with a host of disorders making him Ax-Crazy. Our central focus, everyone. And even if he's just imagining the murders, he's still an unlikable, self-centered, elitist, racist, shallow bastard.
Would Hurt a Child: He stabs a small boy to death just to see if he'd enjoy it. He doesn't... because he doesn't find it evil enough.