In the current version of the ICD-11 manual, the various forms of personality disorders are no longer listed. Why?
Yes, the diagnoses were very complex because the distinction based on categories such as borderline or narcissistic often did not work well. It was often not possible to identify a single disorder in patients; symptoms – such as impulsivity and anxiety – could often be assigned to several categories. Therefore, in an empirical study, we investigated what mechanisms or fundamental personal and interpersonal difficulties there might be that are common to all patients with a personality disorder.
How did you go about it?
Our study included a combination of several scientifically validated questionnaires and semi-structured interviews with a total of 534 people from Switzerland and Germany, mostly patients from psychiatric clinics or outpatient therapies. The questions were partly based on the object relationship model of the psychoanalyst Otto Kernberg, who spent his entire life treating and researching severe personality disorders. The questions revolved around the experience of identity, defense mechanisms, dealing with closeness, aggression, moral values and the extent of narcissism.
What was the result?
We have found four key psychological mechanisms that distinguish people with personality disorders from those without.
The ability to be close and to develop long-term relationships as well as the ability to empathize with others were found to be most important. These abilities are often impaired in people with personality disorders due to traumatic experiences. Certain strong defense mechanisms are also characteristic. They are activated under internal or interpersonal stress, operate unconsciously and can be dysfunctional, for example as projection and denial – in contrast to more functional forms such as humor or intellectualization. Finally, people with severe personality disorders often have a fragile and only partially coherent self-image. Another effect: self-questionnaires seem to capture some aspects less reliably than an interview-based assessment.
They say it is now possible to identify a single, general factor that indicates a disorder.
Yes. Based on these four mechanisms in particular – the ability to get close, empathy, defense mechanisms and identity – we were able to determine a general factor, the so-called G factor, which indicates how severe a personality disorder is. Interpersonal problems appear to be a key indicator. Some researchers are now calling for a new term, interpersonal disorder, instead of personality disorder.
Andre Kerber is a psychological psychotherapist in his own practice, lecturer and supervisor and researches at the Free University of Berlin.
Caroline Macinapsychoanalytic psychotherapist, works in her own practice at the Center Évelyne et Jean Kestemberg and at the Maison Verte in Paris.
source
Kerber, A., Macina, C. et al. (2025). Determining essential dimensions for the clinical approximation of personality disorder severity: multi-method study. The British Journal of Psychiatry. DOI: 10.1192/bjp.2025.10347
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