[3] Dimensional models are intended to reflect what constitutes personality disorder symptomology according to a spectrum, rather than in a dichotomous way.
As a result of this they have been used in three key ways; firstly to try to generate more accurate clinical diagnoses, secondly to develop more effective treatments and thirdly to determine the underlying etiology of disorders.
[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.
[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.
[11] 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.
[4] Attempts at presenting an etiological description of personality disorders have been avoided due to the influence of the DSM and its principles in psychiatric research (See history section).
The ‘do no harm principle’ led to Kraepelinian assumptions about mental illness and an emphasis on empirically grounded taxonomic systems that were not biased by unsubstantiated theories about etiology.
[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.
[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.
[16] The development of factor analysis as a popular statistical technique in differential psychology has led to an increase in attempts at finding underlying traits.
Factor analysis has helped illustrate that the full range of relevant personality pathology is not included in the DSM psychiatry nosology.
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] 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.
[6] The Five-Factor assessment of personality disorders has also been correlated with the Psychopathy Resemblance Index of the NEO Personality Inventory, as well as with the individual personality dimensions of the NEO-PI-R.[21] It also resolves several issues regarding the PCL-R psychopathy assessment, as a Five-Factor-based re-interpretation of the PCL-R factor structure shows that the “Aggressive Narcissism” factor taps into facets of low agreeableness (with some contribution of facets of neuroticism and extraversion), and the “Socially deviant lifestyle” factor represents facets of low conscientiousness and low agreeableness.
[25] Hungarian psychiatrist Léopold Szondi formulated in 1935 a dimensional model of personality comprising four dimensions and eight drives ("facets" in DSM V terminology).
This theoretical assumption is made because no mental disorder can currently be understood as existing independently from its symptoms, as other medical diseases can be.
Essentially it is a method of analyzing mutually interacting entities by represented them as nodes which are connected to through relations called edges.
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.
"[33] 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.