I disagree. Sociopaths, narcissists, borderlines, bipolars, et al are found everywhere, every day, among the general population.
It's not like we are rarely exposed to them - it's not like they are rounded up and segregated but somehow manage to make the occasional escape and roam free until they are re-captured.
On the contrary - they are relatives, significant others, friends, neighbors, bosses, employees, co-workers, teachers, authors, physicians, talk show hosts, actors, politicians, clergy, etc.
After enough exposure to them (whether by interaction or observation), even without a formal education leading to a degree, we may not know the precise name for their maladjustment but we do indeed recognize that they are "off," and we often are quite close to the mark when "naming" what we perceive.