Millon (1990) & Beck (1998) and followers have made up EP tales about the types already identified in the diagnostics manual. Somewhat like the paranoid schizophrenic whom I know - he stands in his yard and stares at passing traffic in order to discover who's looking at him - they build a world around what they already believe. The following suggests another route. After all, Prozac taught us that many separate disorders all respond to serotonin manipulations...

JimB


Evolutionary emergence of responsive and unresponsive personalities
Wolf M, van Doorn GS, & Weissing FJ (2008) PNAS. 105(41) 15825-15830.
In many animal species, individuals differ consistently in suites of correlated behaviors, comparable with human personalities. Increasing evidence suggests that one of the fundamental factors structuring personality differences is the responsiveness of individuals to environmental stimuli. Whereas some individuals tend to be highly responsive to such stimuli, others are unresponsive and show routine-like behaviors. Much research has focused on the proximate causes of these differences but little is known about their evolutionary origin. Here, we provide an evolutionary explanation."

More at http://www.pnas.org/content/105/41/15825

References
Millon, T. (1990) Toward a New Personology: An Evolutionary Model. NY: Wiley.
Beck, A. (1998) Cognitive aspects of personality disorders and their relation to syndromal disorders: A psychoevolutionary approach. In R. Cloninger (Ed.), Personality and Psychopathology. American Psychiatric Association, Washington, D. C., 411-429.