It’s in the title! Sociopath and psychopath are interchangeable terms, though it should be mentioned that some people consider psychopathy to be a more serious form of sociopathy (the disorder is on something of a spectrum like autism). Interestingly, neither term is listed in the DSM (the official US catalog of psychiatric disorders).
In this rather beautifully filmed adaptation of the Brett Easton Ellis book, we follow the life of Patrick Bateman (as mentioned in item ten above) as he descends into psychosis. His character is perhaps the most realistic representation of the absence of empathy that typifies sociopathic insanity and any attempt to appearing to care is clearly fake (see, for example, Patrick’s feigned offence at the anti-Jewish comments made by his friends at dinner). By their nature, sociopaths cause intense confusion in those they prey upon. You are love-bombed but left with a feeling of insecurity.
You are told you are beautiful but are left feeling ugly. American Psycho manages to invoke a similar confusion from the viewers when the film finishing leaving the audience wondering whether anything actually happened at all.
A very clever considered manipulation by director Mary Harron.