Identity disturbance in dimensional and categorical models of personality disorder: The incremental value of self-rated identity and narrative identity

Identity disturbance is increasingly considered to drive personality disorder (PD) onset. Previous research has investigated how identity relates to PD using either self-report scales or narratives to assess identity. Few studies have investigated how both operationalizations relate to one another and to models of PD. More so, no study has investigated whether a narrative identity assessment offers additional explanatory power in understanding PD, beyond what is captured by a self-rated identity assessment, or vice versa. We aimed to address these gaps by administering a rating scale measuring (mal)adaptive identity alongside a prompt to write a narrative about a turning point event to 331 individuals aged 18-30 (72.2% female, M-age = 22.56). Using this multimethod approach, we investigated (a) associations of narrative identity dimensions (agency, communion, exploratory processing) with self-rated identity, self- and interpersonal dysfunction, and symptoms of borderline and antisocial PD, and (b) whether these narrative identity dimensions could explain unique variance in self- and interpersonal dysfunction, and borderline and antisocial PD symptoms, above and beyond self-rated identity, and vice versa. Results revealed significant associations among narrative identity, self-rated identity, and models of PD. Furthermore, communion demonstrated incremental value in explaining PD features, beyond what was accounted for by self-rated identity. However, narrative identity did not offer additional explanatory power in understanding self- and interpersonal dysfunction, beyond self-rated identity. Self-rated identity showed incremental value in explaining all PD models, beyond narrative identity. These results emphasize the importance of employing different methodologies for assessing identity in elucidating how identity disturbance manifests in personality pathology.