I have noticed that people who seem to display striking cluster-B
personality disorder profiles
(Narcissistic/Antisocial/Borderline/Histrionic) tend to have parents
who also display a personality disorder in the same cluster, but not
those of the same exact personality disorder as their offspring. I
haven't noticed this with Cluster A or C, but there is reason to
believe that the cluster A disorders, Schizoid/Schizotypal/Paranoid,
are also heritable as a cluster - they tend to show up in people with
family histories of schizophrenia.

If this is true, then we should expect to see high rates of
Narcissistic, Borderline, and Histrionic PD in Black and Hispanic
populations, as these are known to have high rates of Antisocial
Personality Disorder. (I also wouldn't be surprised to see that East
Asians with PDs are heaviest in cluster C, but I can't provide a shred
of evidence to support this particular hunch).


--Mark