Practical implications of ICD-11 personality disorder classifications

The components of ICD-11 and DSM-5-AMPD exhibit interrelations and align closely with specific normal personality traits [24]. However, differences exist between the two diagnostic systems, with a distinct arising in the conceptualization of the fifth dimension: anankastia in ICD-11 versus psychoticism in DSM-5. ICD-11 has eliminated the psychoticism trait due to its features different from PDs [27]. It fails to map the normal traits under the five-factor personality model, while it is incorporated with the antisocial PD [29]. Anankastia, as conceptualized in ICD-11, is closely associated with perfectionism. This trait manifests as a rigid adherence to norms and obligations, featuring emotional and behavioral constraints, such as inflexible control and perseveration. The DSM-5 trait facets corresponding to anankastia include rigid perfectionism and preservation, originating from the low Disinhibition and Negative Affective domains respectively [37]. Anankastia encompasses essential features of obsessive-compulsive PD and certain aspects of narcissistic (e.g., narcissistic perfectionism) and avoidant (e.g., risk aversion and overconcern) PDs. However, the negative associations with Disinhibition (e.g., reversed Disinhibition) do not account for these features [38]. Nevertheless, ICD-11’s anankastia exhibited satisfactory discrimination and validity across various cultures [16].

However, both ICD-11 and DSM-5-AMPD possess their own advantages when referring to anankastia and psychoticism. The ICD-11 provides a more comprehensive coverage of personality pathology compared with DSM-5-AMPD, notably due to the specificity and cohesive placement of anankastia within the overall personality structure in contrast to psychoticism [29]. While the ICD-11’s Anankastia considerably overlaps with DSM-5 obsessive-compulsive PD [39], its rigidity falls short of fully capturing the obsessive-compulsive PD construct [40]. Bach et al. have found a similar superiority in capturing obsessive-compulsive PD using ICD-11, while DSM-5-AMPD excels in capturing schizotypal PD [27]. Additionally, some case reports concentrated on the distinction advocated by the ICD-11 in the disinhibition/ anankastia personality domain, whereas the psychoticism personality domain is a DSM-5-AMPD conceptualized trait [41].

The ICD-11 categorizes PDs into five severity levels: “No impairment, Personality Difficulty, Mild Personality Disorder, Moderate Personality Disorder, and Severe Personality Disorder.” The last three severity levels specifically pertain to clinical disorders, while the first two do not. In contrast, DSM-5-AMPD proposes five levels of impairment in personality functioning: None/ Little (0), Some (1), Moderate (2), Severe (3), and Extreme (4) Table 1. Notably, the ICD-11 not only encompasses the self and interpersonal functioning, but also includes emotional, cognitive, and behavioral manifestations. For instance, this encompasses self-harm and psychotic-like perceptions, such as disturbances in reality testing [42].

At present, a structured clinical interview for the ICD-11 model is unavailable. However, various self-report and clinician-rating scales exist for evaluating disorder severity, and for both normal and disordered personality traits. Long-term studies have underscored the perspective that personality pathology is not solely a criterion-defined disorder, while is also categorized by severity [7]. Notably, the severity of PDs strongly determines impairment and outcome [43]. The Personality Disorder Severity ICD-11 (PDS-ICD-11, 14 items) has been developed to evaluate self and interpersonal dysfunctions as well as emotional, cognitive, and behavioral symptoms, and psychosocial impairments. This measure uniquely captures all features of PD severity as defined in the ICD-11 model [44]. Across diverse samples, including a US community, a New Zealand mental health sample, and a Spanish mixed sample, the PDS-ICD-11 has demonstrated noticeable criterion validity and incremental validity in predicting PD impairments [44]. In a Spanish mixed sample, the PDS-ICD-11 properties are as adequate as those original instruments [45]. Its German version is acceptable in the general population, and its total score is more strongly associated with negative affectivity compared with antagonism and anankastia [46]. Further validation of PDS-ICD-11 in a community mental health sample has exhibited moderate-to-large associations with all clinician ratings, as well as more variable associations with self-report and informant-report measures [47]. Mean scores of PDS-ICD-11 were significantly different across all levels of ICD-11 PD clinician-rated diagnostic levels. In a Danish general population, practical thresholds of 12, 16, and 19 indicated mild, moderate, and severe PD [48]. An additional study of the Clinician-Rating Form of PDS-ICD-11 demonstrated that item-response theory and confirmatory factor analyses support both item functioning and uni-dimensionality [49].

The Scales of Self and Interpersonal Dysfunction (65 items) are based on the ICD-11, including six domains of self- and interpersonal dysfunctions, identity problems, relationship difficulties, and dysfunctional engagements, as well as five personality domains [50]. The psychometric properties of the Scales are excellent, as indicated by the domains and their components’ convergent and discriminant validities. However, the Scales do not cover the emotional, cognitive, and behavioral manifestations, nor the global psychosocial impairments. The scales are only preliminary and do not take the full ICD-11 severity models into account.

Other measures originally developed for the DSM-5-AMPD criterion A have recently been utilized to assess PD severity based on the ICD-11. For example, the Level of Personality Functioning Scale [21], the Level of Personality Functioning Scale - Brief Form [51], and the Level of Personality Functioning Scale-self-report [52] are the reliable measures. The Self and Interpersonal Functioning Scale is a time-efficient support for clinical decision and treatment planning under the ICD-11 framework [53]. Other measures, such as the Semi-Structured Interview for DSM-5 Personality Functioning (STiP5.1), may describe most information needed for determining PD severity based on the ICD-11 [54]. The STiP5.1 has been translated into several versions and proven to be valuable to evaluate personality functioning dimensions. Notably, it has been utilized effectively in different cultural contexts, such as the Czech [55], Estonian [56], and German [57] versions. As a specific tool for assessing personality functioning in adolescence, the Levels of Personality Functioning Questionnaire 12–18 (LoPF-Q 12–18) is available and recommended [58]. In addition, the Inventory of Personality Organization is a self-report measure which can be employed to assess three domains of personality organization [59]. Table 3

Numerous self-report instruments Table 4 [60] have been developed to measure the ICD-11 domains and subjected to the examination of their factor structure, multimethod usage, convergent and discriminant validities with other prominent, dimensional personality models (e.g., the five-factor model of normal traits), and criterion validity for important life outcomes.

The Personality Inventory for ICD-11 (PiCD) was designed to assess five maladaptive traits (Negative Affectivity, Detachment, Dissocial, Disinhibition and Anankastia) of ICD-11, involving 60 items (12 items each domain) [61]. Preliminary results have shown its adequate internal reliability, and convergent and discriminant validities [62]. PiCD has been tested in Spanish community and clinical samples [63] and in Italian adult samples [64]. Results supported the single-dimensionality for the PiCD Negative Affectivity, Detachment, and Dissocial scale items, as well as the bifactor model (confirmatory factor analysis) of PiCD Disinhibition and Anankastic items in Italian samples. All PiCD scales are significantly associated with the impairment in personality functioning [64]. An informant-report version of PiCD is the Informant-Personality Inventory for ICD-11 (IPiC), which facilitates reporting from other perspectives of a target person. In older adults, IPiC and PiCD have exhibited a moderate self-other agreement, which is associated with several important life functioning areas, and they have structural validity at the item level [65].

The Personality Assessment Questionnaire for ICD-11 personality trait domains (PAQ-11) was developed in South Korea for a rapid measurement by clinicians and researchers, exhibiting adequate convergent and discriminant validities with the five-factor model, the DSM-5 trait model and emotional difficulties [66]. When PAQ-11 is applied to a sample from a U.S. community, the findings encompass 4 out of 5 ICD-11 trait domains, namely Negative Affectivity, Detachment, Disinhibition and Anankastia. Additionally, the results prompt inquiries regarding the structural reliability of the Dissociality scale and the discriminant validity of the Disinhibition and Anankastia scales [67].

A recently proposed alternative measure to PiCD, aiming to provide a more detailed and clinically relevant depiction of personality traits, is the Five-Factor Personality Inventory for ICD-11 (FFiCD) [68]. Comprising 121 items and 20 facets, the FFiCD functions as a self-report tool, concentrating ICD-11 maladaptive traits at the facet level, with 47 short scales situated under the facets, providing a nuanced perspective. In a Spanish community sample, the FFiCD has demonstrated strong internal constructs and exhibited high correlations with other scales measuring personality functioning [69]. Other scholars have proposed that the Revised NEO Personality Inventory and the Short-form of the Zuckerman-Kuhlman-Aluja Personality Questionnaire may be complementary to PD measures or FFiCD [70, 71].

The self-report Personality Inventory for DSM-5 (PID-5), involving 220 items, 25 traits facets, and five higher traits, can also be utilized to capture ICD-11 trait domains [23]. To compute the ICD-11 domains, an algorithm based on the 16 PID-5 facet scales has been developed [37]. Both the 16 PID-5 facets in an Iranian community sample [72] and the expanded 18 PID-5 facets (including Suspiciousness and Attention Seeking) in a Canadian psychiatric sample [73] have proven to be reliable and valid to capture the pathological personality traits. In Chinese [74] and Brazilian [75] clinical-PD samples, the PID-5 has exhibited substantial deviations from normative data, suggesting its potential as an instrument for measuring pathological personality traits in psychiatric patients. Additionally, traditional assessments, such as the Minnesota Multiphasic Personality Inventory, may aid clinicians in evaluating ICD-11 personality trait dysfunctions [76].

A specific assessment, particularly for borderline PD, the Borderline Pattern Scale, comprises 12 items and has demonstrated commendable internal consistency and convergent validity [77]. This scale evaluates the four components characterizing the borderline pattern: Affective Instability, Maladaptive Self-Functioning, Maladaptive Interpersonal-Functioning, and Maladaptive Regulation Strategies. Moreover, it exhibits satisfactory internal consistency and convergent validity, as evidenced by its correlation with four established measures: the borderline scales from the Schedule for Nonadaptive and Adaptive Personality [78], the Coolidge Axis II Inventory [79], the Wisconsin Personality Disorders Inventory [80], and the Five Factor Borderline Inventory [81].

According to the ICD-11, scholars have developed a series of patient-centered measures for PD, exhibiting the potential to improve making clinical decisions and treatment and enhance the healthcare standard for PD patients worldwide [85]. Moreover, a community team, The Boston (UK) Personality Project, has suggested that an increased awareness of personality functioning may lead to superior clinical outcomes and satisfaction for treating PDs [86].

The overall severity of PDs serves as a valuable decision-making tool for tailoring personalized medicine and determining appropriate treatment approaches and intensity. This severity level is intricately linked to various aspects, including long-term prognosis, treatment outcomes, risk of dropout, therapeutic alliance, readiness for treatment, risk of self-harm and violence, and susceptibility to dissociation and psychotic-like breaks. Additionally, it plays a role in the coherence of narrative identity, reflective functioning, and epistemic trust [87]. For example, the dialectical behavior therapy (DBT) is one of the psychotherapies for personality disorders. For mild personality disorder, therapists focus mainly on interpersonal problems and other quality-of-life issues, or the less comprehensive DBT may be considered (e.g., skills class and consultation team) with the possibility of more comprehensive treatment if problems do not improve. While for moderate and severe personality disorders, therapists focus primarily on reducing suicidal and self-harm behaviors, therapy interfering behaviors and other seriously destabilizing behaviors, thus they may apply the comprehensive DBT including the individual therapy, skills class, phone coaching, and consultation team action [87].

Psychotherapies can also be tailored based on the prominent trait domains. For patients exhibiting negative affectivity, therapies may aim to regulate anxiety, sadness, and other emotional variations. This involves helping patients to develop tolerance to distress, fostering self-compassion, enhancing mentalization, promoting acceptance of negative emotions, and acquiring stress management skills. Furthermore, research suggests that for individuals with PDs featuring blends of trait domains, treatment targeting prominent facets proves to be beneficial [76].

Individuals exhibiting high psychopathic traits tend to engage in more criminal activities and report a higher frequency of arrests [88]. Moreover, severe PDs are notably prevalent among those involved in homicides [89]. The ICD-11 framework facilitates the early identification of individuals at risk of developing severe PDs, enabling the implantation of timely and appropriate preventive interventions [89]. A significant legal development in the state of Victoria, Australia, underscores the consideration of PDs during sentencing for convicted offenders, highlighting the greater utility of the dimensional approach over the categorical one in forensic mental health [90]. However, challenges in forensic practice arise from potential reliability issues in assessing personality pathology, particularly when relying on self-report questionnaires [54]. Additionally, the ICD-11 diagnosis of “severe personality disorder, borderline pattern” may influence juror attitudes by introducing considerations of diminished responsibility [91].

In alternative settings, such as during the assessment before bariatric surgery, applying the dimensional ICD-11 trait models are suitable procedures for defining personality psychopathology and overall impairments of patients with obesity, which often help tailor interventions and improve surgical treatment outcomes [92].