Dimensional models of personality disorders
In
The way in which these diagnostic dimensions should be constructed has been under debate, particularly in the run up to the publication of the DSM-5. A number of dimensional models have been produced, differing in the way in which they are constructed and the way in which they are intended to be interpreted. There are four broad types of dimensional representation, although others also exist:[1]
- Dimensional representation of the original DSM categories of personality disorders;
- Dimensional representation based on identification of latent traits with the DSM disorders;
- Dimensional representation based on the traits from normal personality research;
- Representation based on integration of dimensional modals, e.g. by using network analysis.
The dimensional approach is included in Section III ("Emerging Measures and Models") of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), where it is described as an "Alternative DSM-5 Model for Personality Disorders."[2]: p.761–781 The decision to retain the old DSM-IV categorical model of personality disorders in DSM-5 was controversial, and efforts continue to persuade the American Psychiatric Association to replace it with the dimensional model in DSM 5.1.[3]
Usage
Dimensional modals are intended to reflect what constitutes
Clinical diagnosis
The "checklist" of symptoms that is currently used is often criticized for a lack of empirical support[5] and its inability to recognize personality-related issues that do not fit within the current personality disorder constructs or DSM criteria.[6] It has also been criticized for leading to diagnoses that are not stable over time, have poor cross-rater agreement and high comorbidity[7] suggesting that they do not reflect distinct disorders.[8] In contrast the dimensional approach has been shown to predict and reflect current diagnostic criteria, but also add to them.[9] It has been argued to be especially useful in explaining comorbidity which is often high for patients diagnosed with a personality disorders.[7] Following from these claims, the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) incorporates a combined categorical-dimensional approach to diagnosing personality disorders [5] based on the degree to which a person shows elevated levels of particular personality characteristics. However one of the issues in using a dimensional approach to diagnosis has been determining appropriate cut off points so as to know who belongs to the category of people requiring treatment, this is partly why both categorical and dimensional diagnoses are included.[10]
Since the categorical model is widely used in clinical practice and has a significant body of research supporting it, its common usage is compelling to laypeople when they are judging the credibility of professional opinion. Therefore, the dimensional approach is often further criticized for being difficult to interpret and less accessible. It is however widely used in some professional settings as the established approach, for example by
Treatment effectiveness
Another suggested usage of the dimensional approach is that it can aid clinicians in developing treatment plans and assessing other mechanisms contributing to patient's difficulty in functioning within the social, personal, or occupational domains. The approach can improve treatment in two ways. Firstly it can enable development of more personalized care plans for individuals based on their adaptive and maladaptive characteristics. Secondly, it means that relevant symptomology which is not considered maladaptive can be considered when developing and evaluating general therapeutic and medical treatment.[4]
Determining cause
Attempts at presenting an
History
Initial development of a categorical model
The adoption of a categorical approach to personality disorders can be understood in part due to
Emerging problems with the categorical model
The dimensional model was developed in response to the limitations of this standard categorical model.[9] The expectations from a Kraepelinian approach were that as systematic research into psychiatric health increased; diagnostic categories would be refined and targeted reliable treatments would be developed.[13] However this reductionist approach to diagnostic categorization has led to disorders with high comorbidity, life course instability, poor treatment effectiveness and poor diagnostic agreement.[1] In addition the findings from psychopathological research have led to an increasing body of evidence suggesting overlaps between normal and maladaptive personality and interrelatedness across disorders.[7] These findings have been further supported by genetic[14] and developmental studies[15] which have constantly pointed towards greater interrelatedness then the diagnostic categories can offer. These consistently disconformity findings, alongside the successful shift to a continuous rather than categorical approach in other areas of research, such as regarding
Development of methodological techniques
Factor analysis
The development of
Dimensional analysis
Dimensional classification techniques show individual multidimensional profiles and therefore they can show information about a personality continuum (from normal to atypical), one such technique is Hybrid modeling.[17] Cut off points can be introduced into these modals to show where a diagnosis may lie. However the number of different rating scales that need to be looked at and the lack of interdisciplinary research between statisticians and psychologists has meant that attempts at finding a ‘worldwide’ criteria for dimensional diagnosis using this method has been of limited success.[17]
Comparative analysis
Analyses have been conducted to test the relative fit of categorical and dimensional modals to evaluate whether single diagnostic categories are suited to either status. These types of analysis can include a range of data, including
Network analysis
Network Analysis has been used as a means of integrating information about personality with personality disorders and as well as information about other genetic, biological and environmental influences into a single system and looking at interrelated causalities between them (See integrated modals).
Model development
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Adapted categorical models
There are different ways to ‘dimensionalize’
- The first involves quantifying DSM-5 pathology. This can be done either based on the degree to which symptoms are present or on how close to a prototypic presentation a patient's presentation may be. The prototype approach includes features not present in the DSM.[18]
- The second approach involves identification of DSM disorder traits by means of factor analysis to show underlying dimensions of the personality disorder criteria, this method may also include relevant psychopathology.[17]
Normal personality models
Five-factor model
The Five-Factor model of personality, which is the most dominant dimensional model,[19] has been used to conceptualize personality disorders and has received various empirical support. Under this approach, extreme levels of the basic personality traits identified by the FFM are what contributes to the maladaptive nature of personality disorders.[20] Over 50 published studies supporting this model have been identified, providing much empirical support for this approach. Most of these studies examine the relationship between scores on separate measures of Big Five trait and personality disorder symptoms.[20]
The Five-Factor model was first extended to personality disorders in the early 1990s, when it was established that a satisfactory profile of each personality disorder in the
A prototype diagnostic technique has been developed in which Five-Factor-based prototypes for each disorder were created, based on the aggregated ratings of personality disorder experts. These prototypes agree well with DSM diagnostic criteria.[20] The Five-Factor prototypes also reflected the high comorbidity rates of personality disorders. This is explained by the idea that various other disorders tap into dimensions that overlap with those of the primary diagnosis.[20]
Another Five-Factor based technique involves diagnosing personality disorders based on clinician ratings of various facets of the five factors (e.g. self-consciousness, which falls under the neuroticism factor; excitement seeking, which falls under the extraversion factor). This technique is partially based on the prototype model, as each facet's "score" is based on its rating of how prototypical it is of each personality disorder, with prototypically low facets (with a score less than 2) reverse-scored. Using this technique, diagnosis is based on an individual's summed score across relevant facets. This summed-score technique has been shown to be as sensitive as the prototype technique, and the easier computation method makes it a useful suggested screening technique.[6]
The Five-Factor assessment of personality disorders has also been correlated with the Psychopathy Resemblance Index of the
Criticism
The dimension of openness to experience of the Five-Factor model has been criticized for not directly relating to any of the major characteristics of personality disorders in the same way as do the other four dimensions [
Seven factor model
The Five-Factor approach has been criticized for being limited in some respects in its conceptualization of personality disorders. This limitation is due to the fact that it does not include evaluative trait terms such as “bad”, “awful”, or “vicious”. Some research has suggested that two evaluative dimensions should be added to the Five-Factor model of personality disorders. Empirical support for this approach comes from factor analyses that include the Big Five factors and evaluative terms. These analyses show that the evaluative terms contribute to two additional factors, one each for positive and negative valence. The addition of these two factors resolves much of the ambiguity of the openness dimension in the Five-Factor approach, as the openness factor changes to a conventionality factor, and adjectives such as “odd”, “strange”, and “weird” (which all characterize schizotypal personality disorder) fall onto the negative valence factor. These results indicate that the inclusion of evaluative terms and valence dimensions can be valuable for better describing the extreme and maladaptive levels of personality traits that comprise personality disorder profiles.[5]
Internalizing/Externalizing model
A two-factor model of psychopathology in general has also been suggested, in which most disorders fall along internalizing and externalizing dimensions,[23][24] which encompass mood and anxiety disorders, and antisocial personality and substance use disorders, respectively.[24] Although this approach was originally developed to understand psychopathology in general, it has often been focused to apply to personality disorders, such as borderline personality disorder to help better understand patterns of comorbidity.[25]
Szondi drive theory
Hungarian psychiatrist Léopold Szondi formulated in 1935 a dimensional model of personality comprising four dimensions and eight drives ("facets" in DSM V terminology). It was based on a drive theory, in which the four dimensions correspond to the independent hereditary circular mental diseases established by the psychiatric genetics of the time:[26] the schizoform (containing the paranoid and the catatonic drives), the manic-depressive (for the "contact" dimension), the paroxysmal (including the epileptic and hysteric drives), and the sexual drive disorder (including the hermaphrodite and the sadomasochist drives).[27] The Sex (S) and Contact (C) dimensions can be further grouped as representing pulsions at the border with the outer world, while the Paroximal (P) and Schizoform (Sch) dimensions at the inner part of the psyche.
Integrated models
Network analysis
Therapeutic consequences
The therapeutic consequence of this is that treatment is targeted at the symptoms themselves and the causal relations between them, not the overarching diagnosis. This is because targeting the diagnosis is trying to treat an unspecified summary of a complex collection of causes. Adopting this attitude sits well with the therapeutic treatments in use at the moment that have the strongest evidence base.[29]
Network construction
Network analysis has its roots in mathematics and physics but is increasingly being used in other areas. Essentially it is a method of analyzing mutually interacting entities by represented them as nodes which are connected to through relations called edges. Edges represent any sort of relation such as a partial correlation. Complex network analyses of other subjects have looked at tipping points, where one system suddenly transitions into another, such as when a tropical forests goes into a savannah. If these could be identified in individual's psychopathological dynamic networks then they could be used to determine when a person's network is on the brink of collapse and what can be done to alter it.[29]
Criticisms
There are concerns that the network modal does not have enough parsimony and is too difficult to interpret.[30]
DSM-5
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The Personality and Personality Disorder Work Group proposed a combination categorical-dimensional model of personality disorder assessment that will be adopted in the DSM-5. The Work Group's model includes 5 higher-order domains (negative affectivity, detachment, antagonism, disinhibition, and psychoticism) and 25 lower-order facets, or constellations of trait behaviors that constitute the broader domains. The personality domains can also be extended to describe the personality of non-personality disorder patients. Diagnosis of personality disorders will be based on levels of personality dysfunction and assessment of pathological levels of one or more of the personality domains,[31] resulting in classification into one of six personality disorder "types" or Personality Disorder Trait Specified (depending on the levels of traits present), in contrast to the current traditional categorical diagnoses of one of 10 personality disorders (or personality disorder not otherwise specified) based on the presence or absence of symptoms.[32]
Criticism
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There are concerns that the addition of dimensional models to DSM-5 may raise confusion. Carole Lieberman has stated that "As it is now, people don't really make use of the subcategories that there are to describe severity of symptoms. Instead, I see this as a tool that insurance companies could well co-opt to try to deny benefits."[33]
References
- ^ PMID 17716092.
- ISBN 978-0-89042-555-8.
- PMID 24378161.
- ^ PMID 17492921.
- ^ .
- ^ S2CID 17459349.
- ^ PMID 15939839.
- PMID 16351377.
- ^ PMID 19167138.
- ^ PMID 17623397.
- ISBN 0-471-38321-X.
- ^ S2CID 33336473.
- S2CID 144085712.
- S2CID 39325010.
- PMID 11097968.
- PMID 25581244.
- ^ a b c Helzer, J. E., Kraemer, H. C., Krueger, R. F., Wittchen, H. U., Sirovatka, P. J., & Regier, D. A. (Eds.). (2009). Dimensional approaches in diagnostic classification: Refining the research agenda for DSM-V. American Psychiatric Pub.
- PMID 15465966.
- ^ S2CID 17468718.
- PMID 11339798.
- PMID 18072861.
- PMID 9604551.
- ^ PMID 21842958.
- PMID 20836905.
- ^ Ellenberger, H. (1970) The Discovery of the Unconscious, p.866
- ^ Szondi (1972) pp.34-6 quotation:
Ein Triebststem muß aus Triebgegensatzpaaren konstituiert werden, die einerseits in jedem Individuum vorhanden sind, andererseits mit den pathopsychologischen, d.h. Psychiatrischen Erbkreisen genau übereinstimmen. (...) Die psychiatrische Vererbungslehre hat bisher drei selbständige Erb Kreise der Geisteskrankheiten festgestellt.
- PMID 22114671.
- ^ PMID 23537483.
- PMID 23067258.
- ^ "Personality Disorders". DSM-5 Development - Proposed revisions. American Psychiatric Association. Archived from the original on 13 May 2012. Retrieved 18 April 2012.
- PMID 22428791.
- ^ Gever, John (February 10, 2010). "DSM-V Draft Promises Big Changes in Some Psychiatric Diagnoses". Retrieved 16 April 2012.
Further reading
- Brown, TA; Barlow, DH (November 2005). "Dimensional versus categorical classification of mental disorders in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders and beyond: comment on the special section". Journal of Abnormal Psychology. 114 (4): 551–6. PMID 16351377.
- De Clercq, Barbara; De Fruyt, Filip; Widiger, Thomas A. (2009). "Integrating a developmental perspective in dimensional models of personality disorders". Clinical Psychology Review. 29 (2): 154–162. PMID 19167138.
- Harkavy-Friedman, J. M. (2009). "Dimensional Approaches in Diagnostic Classification: Refining the Research Agenda for DSM-V". American Journal of Psychiatry. 166 (1): 118–119. ISSN 0002-953X.
- Helzer, John E.; van den Brink, Wim; Guth, Sarah E. (2006). "Should there be both categorical and dimensional criteria for the substance use disorders in DSM-V?". Addiction. 101: 17–22. PMID 16930157.
- Krueger, RF; Skodol, AE; Livesley, WJ; Shrout, PE; Huang, Y (2007). "Synthesizing dimensional and categorical approaches to personality disorders: refining the research agenda for DSM-V Axis II". International Journal of Methods in Psychiatric Research. 16 Suppl 1 (Suppl 1): S65-73. PMID 17623397.
- Livesley, WJ (April 2007). "A framework for integrating dimensional and categorical classifications of personality disorder". Journal of Personality Disorders. 21 (2): 199–224. PMID 17492921.
- Livesley, WJ (April 2005). "Behavioral and molecular genetic contributions to a dimensional classification of personality disorder". Journal of Personality Disorders. 19 (2): 131–55. PMID 15899713.
- Paris, Joel (April 2005). "Neurobiological dimensional models of personality: a review of the models of Cloninger, Depue, and Siever". Journal of Personality Disorders. 19 (2): 156–70. PMID 15899714.
- Pukrop, R (2008). "[Toward DSM-V: new approaches for the classification of personality disorders]". Praxis der Kinderpsychologie und Kinderpsychiatrie (in German). 57 (8–9): 610–24. S2CID 145063778.
- Ryder, AG; Bagby, RM; Schuller, DR (Nov–Dec 2002). "The overlap of depressive personality disorder and dysthymia: a categorical problem with a dimensional solution". Harvard Review of Psychiatry. 10 (6): 337–52. PMID 12485980.
- Sprock, J (September 2003). "Dimensional versus categorical classification of prototypic and nonprototypic cases of personality disorder". Journal of Clinical Psychology. 59 (9): 991–1014. PMID 12945064.
- Trull, Timothy J.; Durrett, Christine A. (2005). "Categorical and Dimensional Models of Personality Disorder". Annual Review of Clinical Psychology. 1 (1): 355–380. PMID 17716092.
- Trull, TJ; Tragesser, SL; Solhan, M; Schwartz-Mette, R (January 2007). "Dimensional models of personality disorder: Diagnostic and Statistical Manual of Mental Disorders Fifth Edition and beyond". Current Opinion in Psychiatry. 20 (1): 52–6. S2CID 33336473.
- Verheul, R (June 2005). "Clinical utility of dimensional models for personality pathology". Journal of Personality Disorders. 19 (3): 283–302. PMID 16175737.
- Widiger, TA (June 2007). "Dimensional models of personality disorder". World Psychiatry. 6 (2): 79–83. PMID 18235857.
- Widiger, TA; Simonsen, E (April 2005). "Alternative dimensional models of personality disorder: finding a common ground". Journal of Personality Disorders. 19 (2): 110–30. PMID 15899712.
- Widiger, TA; Livesley, WJ; Clark, LA (September 2009). "An integrative dimensional classification of personality disorder". Psychological Assessment. 21 (3): 243–55. PMID 19719338.
- Widiger, Thomas A.; Frances, Allen J. (2002). "Toward a dimensional model for the personality disorders.". Personality disorders and the five-factor model of personality (2 ed.). pp. 23–44. ISBN 1-55798-826-9.