Rigid and extreme: a geometric representation of personality disorders in five-factor model space.

Personality disorder rigidity and extremity can be geometrically defined and operationalized within the 5-factor model (FFM) of personality. A series of geometric and substantive assumptions were derived and then tested in samples of college students (N = 1,323) and psychiatric patients (N = 86). Normal and disordered personalities were found to coexist in a variety of regions of the FFM multivariate space. Within regions, the profiles of normal and disordered personalities were very similar in characteristic configuration but notably different in profile variability. Personality-disordered individuals tended to be located in the perimeters or outer regions of the FFM space, as indicated by their longer vector lengths. These findings generalized across 2 measures of personality disorders and across 2 measures of normal personality traits.