In ICD-11, aspects of self-function are evaluated on a severity scale when conceptualizing and diagnosing PD. Autobiographical reasoning in narrative identity could be integrated in a similar way, to nuance the coherence aspect of the self-function (see Table 1 for a tentative suggestion). Moving forward, it will be crucial to identify clear cut-off points (i.e., narrative markers) to determine when the autobiographical reasoning converts from being adaptive to mildly-severely disturbed. Lind, Thomsen and colleagues (16) showed that differences in narrative identity predicted group membership (PD vs. control) even after controlling for depressive symptoms—an important first step. Since associations have been shown between inpatient adolescents with PD features and problematic chronological and thematic coherence [(14), Lind et al., under review], autobiographical reasoning could be a critical precursor of full-blown PD together with other identity aspects (22, 23). Because narrative chronology emerges earlier in development than thematic coherence, the former may be used as a more robust narrative marker of early on-set of maladaptive development. Future research should also clearly map out the unique aspects of autobiographical reasoning related to PD and those that might tap into a general p factor (24).

Narrative identity is typically assessed using the Life Story Interview (25). This semi-structured interview provides rich material on the person's own interpretation on the self and the lived life. Narrative characteristics such as autobiographical reasoning are then assessed using previously validated coding systems. Some crucial aspects must, however, be considered before integrating existing narrative identity assessment in the context of PD. First, the LSI prompts for a prototypical life story and narration in Western countries. It may not adequately capture the normative reasoning and story-telling in other parts of the world, in which some adjustment will be required. Second, autobiographical reasoning covers a niche of personally significant reasoning distinctive from general cognitive difficulties. For example, the disturbances related to autobiographical reasoning in PD were evident even when the control group considered was matched on education [e.g., (11, 15, 16)]. Finally, existing assessment is based on the typically developing personality and, while researchers have started to create coding systems from a clinical stance (e.g., Lind and Dunlop, unpublished coding manual), more is needed to accurately assess personality (dys)functioning within ICD-11. Echoing Hoopwood (26), clinical and basic personality psychologists interact with each other less than they should. This would be a golden opportunity to do so, especially since no official instrument yet exists assessing self- and interpersonal functioning in ICD-11 [e.g., (1, 21)]. In DSM-5's Alternative Model for Personality Disorders [e.g., (27)], identity is evaluated based on the subdomains of self-differentiation, self-esteem, and emotional range and regulation and do not adequately capture the coherent sense of self as it is articulated in ICD-11. As such, adopting existing assessment from DSM-5 may be less than ideal if the temporal aspect of the self should be adequately integrated within forthcoming measurements.

Both written (28) and video-material (29) of the LSI have been used to successfully assess levels of self-functioning in community samples whereas the other-function (e.g., mentalization) were more challenging to assess. Recently, a modified LSI version was used to assess people with BPD's vicarious life story of a parent. That is, the patients were asked to tell their mother or father's life story—to put themselves in their parent's shoes and elaborate and reflect on this story from the parent's perspective (Lind et al., in preparation). Aspects of autobiographical reasoning (i.e., a temporal other- reasoning) and meta-cognition (30), a concept related to mentalization, were successfully assessed. The vicarious perspective (31) could be a fruitful area for future assessment of other-functioning in ICD-11.

Prominent researchers in the field have suggested that the severity of personality functioning can be used as a decision tool to determine the optimal treatment and treatment intensity in a “personalized medicine manner” (22). Given the importance of a coherent identity in ICD-11 [e.g., (1)], the narrative identity seems significant. Several prominent researchers and clinicians [e.g., (32–35)] have emphasized the relevance of integrating narrative identity within psychotherapy. In my own research, I stress the importance of implementing narrative identity within treatment of PD [e.g., (10, 14, 15)] and particularly in the context of the dimensional model (Lind et al., under review, see also 27). Bach and Simonsen (21) further suggested that narrative identity could be a potential mechanism of change in therapy, especially for moderate-to-severe personality disorders in the context of ICD-11. Integrating narrative identity within a treatment setting has several advantages: first, it fits within “personalized/narrative medicine” by emphasizing the importance of a person's unique life, and second, it offers an empathic setting in which the therapist is giving voice and ownership to the patient's story creating a unique and vulnerable window into the person's sense of self nurturing epistemic trust [i.e., the willingness to consider new knowledge as trustworthy and relevant to the self: (36)] and building a working alliance with the patient (21). In Table 1, I offer tentative suggestions on how autobiographical reasoning can be considered within a therapeutic context and dependent on the severity of functioning in ICD-11. Importantly, the origin and underlying mechanisms of reasoning difficulties are complex and can be interpreted and treated from multiple therapeutic approaches. Together with close colleagues, I have recently developed a narrative repair guide to assist people with mental illness in gaining enhanced insight and more adaptive story telling (Thomsen et al., under review). This guide could be helpful in the context of PD and likely in combination with more cognitive evidence-based treatments. However, approaches that perceive the reasoning abnormalities as emanating from splitting-based defense mechanisms [e.g., (17, 37)] or mentalizing difficulties (38) endorsing psychodynamic interventions may also be effective. For example, themes of narrative agency were improved in people manifesting PD after psychodynamic therapy (15). That is, the self has been highlighted as a driver of personality functioning [i.e., Criterion A; (39)]. Strengthening autobiographical reasoning (i.e., the self as author) may scaffold a healthy organization of personality regardless of whether these reasoning challenges are interpreted from a more cognitive or psychodynamic perspective.