LOL!
ROTFLOL!
GTTM!
I know a number of English teachers and fellow psychologists at my college who'd shake their heads in disbelief at that thoroughly inaccurate assertion!
Of course, I suppose, in the case of a Multiple Personality Disorder, there COULD be a case made for using persopnaliTIES. LOL.
But you weren't writing about MPD's.
In college, I used to have English professors.
For a psychologist, or whatever you claim to be, you ought to know that a "personality" is a sum total of more than one factor. To say that a perosanlity is an amalgam of different elements is not the same as saying there are mutiple personalities.