I don't think the term "psychopath" is used clinically anymore, except by Hare et al. who insist that there is a difference between sociopathy and psychopathy. I have read at least 5 separate explanations of the differences between the two, but I couldn't tell one from the other. Even the DSM-IV criteria for antisocial personality disorder are quite vague, as I see it. Aside from Hare, other psychologists like Millon have basically introduced their own classifications of people with antisocial tendencies. Millon's subtypes are even less useful because they overlap other personality disorders, like narcissistic, schizoid, and histrionic.

But consider Mr. X, who has several characteristics of schizoid personality, was described as alexithymic by a clinical psychologist, scored an 8 Simon Baron-Cohen's Empathy quotient[1] (whereas most people with Asperger Syndrome or high-functioning autism score about 20), scored equally low on the Social Interaction Anxiety Scale (SIAS)[2]. If Mr. X shows any kind of aggression, he might very well be considered to have ASP. Without the aggression, he seems to fall somewhere in the Autism spectrum.

Then there are also conduct and dissocial disorders, which have a lot in common (lying, stealing, violent behavior) with ASD. As far as I know, only the ICD-10 definition of ASD attempts to rule out conduct disorder.

To me it seems like most of the terms in the antisocial realm are pretty much generic labels that aren't very useful. The "psychopath" kind of touched on that implicitly in his letter a few times. It's at least some food for thought.

1 - http://glennrowe.net/BaronCohen/EmpathyQuotient/EmpathyQuoti...

   (this is not a test used in clinical settings)

2 - http://cooccurring.org/public/document/sias.pdf