Towards harmonisation of DSM-6 with ICD-11 personality disorder classification

The newest suggestion for a revised DSM-5 AMPD (proposal for DSM-6), recently put forward by Sharp and colleagues, ^{Reference Sharp, Clark, Balzen, Widiger, Stepp and Zimmerman4} introduces a global dimensional scale to align with the ICD-11 model. Moreover, these authors suggest adding a distinct compulsivity trait domain that provides further consistency with the ICD-11 trait domain of anankastia. The only major difference now is that the proposed AMPD revision still includes a separate trait domain of psychoticism covering certain Schneiderian features of thought control and thought broadcasting, ^{Reference Sharp, Clark, Balzen, Widiger, Stepp and Zimmerman4} which are considered to be part of the schizophrenia spectrum in ICD-11. ICD-11 does recognise the well-documented significance of reality distortions when describing the most severe levels of personality disorder (e.g. ‘psychotic-like beliefs or perceptions’, ‘dissociative states’ and ‘a self-view that may be highly eccentric’). ^{Reference Cavelti, Thomson, Kaess and Bach7} Although such manifestations of personality dysfunction may not be explicitly included in the AMPD’s description of personality functioning, they remain consistent with the shared conceptual foundation of personality. Complete harmonisation of the ICD and DSM would lead to loss of the psychoticism trait domain in the revised AMPD (consistent with schizotypy) as a condition better diagnosed globally within the genetically shared psychosis spectrum in the ICD system. ^{Reference Cavelti, Thomson, Kaess and Bach7}

The only way forward for the classification of personality disorder

In terms of the necessary compatibility, DSM-5-TR no longer provides its own diagnostic codes, because these have now been fully and exclusively replaced by ICD-10 codes to facilitate insurance reimbursement and for monitoring of morbidity and mortality statistics by health agencies. Thus, when the revised AMPD framework is fully adopted in the forthcoming DSM-6, there will be no other way forward than to use ICD-11 codes for the corresponding severity levels and trait domain specifiers. ^{Reference Clark3,Reference Sharp, Clark, Balzen, Widiger, Stepp and Zimmerman4,Reference Krueger8} It is therefore our strong belief that the ICD-11 personality disorder classification, shared by all WHO member states, provides the most reasonable common framework for clinicians and researchers, allowing a shared goal of reducing the global disease burden associated with personality disorder. At the same time, to be widely used and influential, a classification system of personality disorders must meet the needs of both busy clinicians with limited resources (e.g. determining the overall presence of personality disorder; at least ‘mild personality disorder’) and highly trained specialists with a wealth of resources (e.g. allowing the determination of severity, portraying aspects of personality functioning and characterising individual trait expressions). ^{Reference Bach, Mulay and Yalch6} We believe that the ICD-11 classification of personality disorder is most feasible for meeting both of these conditions.

Personality disturbance in all its forms has a major impact on the outcomes of most mental and physical illness, and awareness of its presence should be an essential part of clinical understanding in healthcare services. Acceptance of one shared and harmonised diagnostic system for personality disorder would therefore be a great boon not only for practitioners and all concerned with the global prevalence of disease ^{Reference Moran, Romaniuk, Coffey, Chanen, Degenhardt and Borschmann9} but also for patients currently weighed down by the stigma, ignorance and neglect associated with this diagnosis. ^{Reference Stricker, Hasenburg, Jakob, Weigl and Pietrowsky5} A dimensional classification that is easy to follow, that widens the spectrum of personality disturbance to include all personality dysfunction and loses all the current stigmatising labels is ready to be embraced by all practitioners within mental health. Rather than continuing to develop adjacent models with differences so minor that they cannot add anything meaningful, we now need a unified focus on the uptake and implementation of the classification of personality disorder by clinicians and health systems. As the DSM-5-TR (and eventually the DSM-6) no longer uses its own codes but exclusively relies on ICD codes, avoiding the ICD-11 classification of personality disorders is futile. Eventually, a revised AMPD model within DSM-6 will be required to harmonise with ICD-11 codes. Furthermore, as a non-profit and non-commercial classification system, WHO’s freely accessible personality disorder classification seems to be the most appropriate path forward for our global community, consistent with principles of equity, fairness and clinical utility.