Gone Girl as psychopath or sociopath?

After finishing the novel…

Jill: It was a disquieting book. That Amy had this mask of sanity in her first diary and then she went psychopathic in her second diary.

Nigel: She turned into a sociopath.

Jill: Well, her personality flaws seemed to be innate, like a psychosis.

Nigel: But at the end, what she did to Desi, that was sociopathic. Anyway, it was an unsatisfying ending.

Jill: Some see it as symmetrical. They deserved each other.

Nigel: Symmetrical? Nick wasn’t in Amy’s league for evil.

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Voice-over

 “Psychopath” and “sociopath” are sometimes used interchangeably. Robert Hare, who devised a Psychopathy Checklist, suggested a distinction. Psychopathy might be more relevant for referring to disorders caused by biological or genetic factors, but sociopathy might be a result of environment and social factors. Was it Amy's genes or upbringing that made her turn out like that?

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