5b
Peter Tyrer
This erudite and well-informed chapter by Joel Paris is marred only by the absence of answers to the difficult questions posed. What is very clear from all the debate in the last 20 years about personality disorder is that mixed, or hybrid, solutions are not viable. What is described as hybrid vigor by geneticists becomes hybrid failure in classification. So, firm responses are needed, and good responses are those that provide answers too. As an introduction to this commentary, I ask four questions:
1.Who is a classification for?
2.Should a classification in psychiatry be based on clinical utility or science?
3.Is one of the main purposes of a good classification to help in making clinical decisions?
4.Is the long-running argument about categorical and dimensional classification of personality disorder a dead issue?
Who Is a Classification For?
This question can be answered quite easily. A classification is for the people who are expected to use it. A good classification is used frequently and, if really successful, universally. None of the classifications of personality disorder discussed by Joel Paris have been embraced with enthusiasm by health professionals. Paris highlights the great use of PD-NOS as a diagnosis in clinical practice; the very fact that no formal diagnosis is being made, as well as the fact that the diagnosis has no coherent structure (Verheul, Bartak, & Widiger, 2007), illustrates the complete poverty of the categorical classification as it stands.
Most people who debate the merits and demerits of the classification system are those involved in the tertiary management of people with personality disorder or psychologists interested in the whole range of personality variation. However, many more should have an interest in this issue, but are turned off by the complexity and absurdity of the many arguments for and against the different systems that ping about interminably on the personality pinball machine. This is a crying shame; every general practitioner and physician across the world should know how to diagnose personality disorder. One can go further. A condition that affects 10 percent of the whole adult population needs to be appreciated by all health professionals, not just by a select few who spend their lives seeing a very small proportion of the total sufferers.
Should a Classification in Psychiatry Be Based on Clinical Utility or Science?
The pat answer to this question is that science should always win. However, we know in psychiatry that we are highly vulnerable to criticism that our diagnoses are suspect, as we have so few independent biological markers. This is where clinical utility takes over. We may not know exactly how pathological depression manifests itself in the human brain, but clinicians have a clear idea when it is present and when it appears to be pathological.
Those who support the categorical classification of personality disorder, and this includes Joel Paris in respect to borderline and antisocial personality disorder (although not the others), maintain that something important is lost by removing existing clinical characteristics and replacing them with dimensions. This is understandable when many years have been spent developing treatments for borderline personality disorder in particular, and practitioners fear that something important will be lost if these descriptions are abandoned.
But science has to intrude. It is a sad fact that there is no independent evidence worthy of scientific scrutiny that supports the existence of any of the personality disorders described in DSM-IV or DSM-5. Time after time, they have been shown to be wanting when subjected to independent scrutiny. The dimensional system, by comparison, comes out extremely well in scientific terms (Widiger, 2007). Personality dysfunction can be seen on a continuum with no clear defining points, and the five factor model of normal personality variation can extend into the pathological spectrum without any difficulty (Widiger, Livesley, & Clark, 2009).
Is One of the Main Purposes of a Good Clinical Classification to Help in Making Clinical Decisions?
It is one of the curious fictions that a psychiatric classification should be considered independently of treatments. This is understandable at one level, as we do not want to see conditions such as “antipsychotic deprivation syndrome” or “danger in the community disorder” being adopted in the psychiatric lexicon.
However, this does not mean that clinical decisions should be divorced from the classification debate. One of the strong points made in favor of keeping borderline personality disorder is the large amount of clinical research and treatment studies that give hope and purpose to clinicians, and this is rightly stressed by Paris. It is also one of the reasons why there was so much concern about losing the diagnosis in ICD-11 (Herpertz et al., 2017).
Is the Long-Running Argument about Categorical and Dimensional Classification of Personality Disorder a Dead Issue?
The answer to this question is a clear “no” from a quick glance through the rest of this book. The debate remains in full force, but the trends are becoming apparent. The alternative DSM-5 model for personality disorders described by Joel Paris is rapidly becoming the official DSM-5 version because it has been convincingly and carefully developed by Robert Krueger and his colleagues with useful complementary material to aid their dimensional system (Krueger, Derringer, Markon, Watson, & Skodol, 2012). The one categorical diagnosis that has refused to lie down and die is borderline personality disorder.
Advantages of the ICD-11 Classification of Personality Disorder
The World Health Organization published the ICD-11 classification of personality disorder on June 18, 2018 (WHO, 2018). The fundamental elements of the previous version of the classification were preserved (Tyrer et al., 2011; Tyrer, Reed, & Crawford, 2015) and, although there was concern about the radical nature of the reclassification, there was virtually no published criticism until 2017 when important voices were raised by the personality disorder community (Herpertz et al., 2017). These in turn raised a counter-punch from those who support a dimensional system (Hopwood et al., 2018). However, despite the apparent complexity of the arguments, the pugilists were really fighting over one issue: the fate of borderline personality disorder. As Joel Paris has suggested, if the other personality disorder diagnoses described in DSM-III – histrionic, schizoid, schizotypal, avoidant, dependent, narcissistic, and obsessive-compulsive – all became dimensional overnight, few would object. But borderline and, to a lesser extent, antisocial personality disorder are different. They had a body of adherence and support backed up by other bodies, such as the insurance companies, who liked the clear descriptions of the disorders and their diagnostic criteria.
The ICD-11 classification of personality disorders attempts to give helpful answers to all the questions at the beginning of this chapter. First of all, it is a classification for the majority of health professionals. Many years ago, I became an honorary member of the Central Africa Witchdoctors Association when leading a student expedition to find new pharmacological agents from medicinal plants. My fellow witchdoctors, or n’angas, were familiar with different personalities when carrying out their treatment rituals, and, in particular, knew the relationships people had with other village members. They, I am sure, would have been able to place each of their patients at an appropriate place on the severity scale of personality impairment and adjust their treatment accordingly. This is because the fundamental component of personality status, interpersonal social dysfunction, is one of the easiest to identify. It is possible for all practitioners to stop at the first level of personality assessment. For some patients with very severe personality disorder, it may be difficult for a practitioner to make an accurate assessment of domain traits in an ordinary community setting, but still possible to determine enough about severity to decide that corrective action is needed.
The ICD-11 classification also allows for much better assessment of the effects of treatment. The current dichotomous classification does not allow for variation in personality function to be reflected over time. It is well known that personality function fluctuates, both spontaneously (Clark, 2007) and in response to treatment, and the current classification makes no allowance for this. For disorders where complex treatments are recommended (Department of Health, 2009), it is also important to specify the severity of the personality disorder and probably forgo long-term treatments if the disorder is only mild in severity.
Finally, the place of borderline personality disorder is, at least temporarily, assured. There are some who would prefer all categories to be excluded in what is otherwise a dimensional system, but the arguments for inclusion of a “borderline pattern descriptor” have been strong and many will be pleased to recognize familiar words in this pattern below, now accepted in ICD-11:
The Borderline pattern descriptor may be applied to individuals whose pattern of personality disturbance is characterized by a pervasive pattern of instability of interpersonal relationships, self-image, and affects, and marked impulsivity, as indicated by many of the following: Frantic efforts to avoid real or imagined abandonment; A pattern of unstable and intense interpersonal relationships; Identity disturbance, manifested in markedly and persistently unstable self-image or sense of self; A tendency to act rashly in states of high negative affect, leading to potentially self-damaging behaviours; Recurrent episodes of self-harm; Emotional instability due to marked reactivity of mood; Chronic feelings of emptiness; Inappropriate intense anger or difficulty controlling anger; Transient dissociative symptoms or psychotic-like features in situations of high affective arousal.
(World Health Organization, 2018)
However, if the dimensional view of personality classification becomes the norm, the borderline pattern may merge imperceptibly into the general structure of personality disorder, provided that clinicians can embrace its positive attributes. This is not yet certain (Tyrer, 2018).
A few years ago, I was in Long Island in a meeting concentrating almost entirely on borderline personality disorder. On the last day of the meeting, James D. Watson, Nobel prize winner for his work on eliciting the structure of DNA, commented to me after the meeting closed, “Why all this obsession with borderline personality disorder? What about the others? You are not going to get the answer to personality disorder just by working on borderline.” I heartily concur.
References
Clark, L. A. (2007). Assessment and diagnosis of personality disorder: Perennial issues and an emerging reconceptualization. Annual Review of Psychology, 58, 227–257.
Department of Health. (2009). Borderline Personality Disorder: Recognition and Management. NICE Clinical Guideline [CG78]. London: Department of Health.
Herpertz, S. C., Huprich, S. K., Bohus, M., Chanen, A., Goodman, M., Mehlum, L., … Sharp, C. (2017). The challenge of transforming the diagnostic system of personality disorders. Journal of Personality Disorders, 31, 577–589.
Hopwood, C. J., Kotov, R., Krueger, R. F., Watson, D., Widiger, T. A., Althoff, R. R. … Zimmermann, J. (2018). The time has come for dimensional personality disorder diagnosis. Personality and Mental Health, 12, 82–86.
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Tyrer, P. (2018). Dimensions fit the data, but can the clinicians fit the dimensions? World Psychiatry, 7, 295–296.
Tyrer, P., Crawford, M., Mulder, R., Blashfield, R., Farnam, A., Fossati, A., … Reed, G. M. (2011). The rationale for the reclassification of personality disorder in the 11th revision of the International Classification of Diseases (ICD-11). Personality and Mental Health, 5, 246–259.
Tyrer, P., Reed, G. M., & Crawford, M. J. (2015). Classification, assessment, prevalence and effect of personality disorder. Lancet, 385, 717–726.
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World Health Organization. (2018). International Classification of Diseases (11th revision, ICD-11). Geneva: World Health Organization. www.who.int/classifications/icd/