In light of the DSM-5 dimensional model of personality: Borderline personality disorder at the crossroads with the bipolar spectrum

Highlights

• DSM-5 pathological traits as predictors of borderline PD through bipolar spectrum.

• Depressivity and impulsivity traits displayed the greatest differential values.

• Common discriminants features are unusual beliefs, paranoid, obsession, extraversion.

• Assessment based on pathological/normative traits and symptoms is reinforced.

Abstract

Background. State-of-the-art research highlights that borderline personality disorder (PD) and bipolar spectrum disorders have clinical characteristics in common, which imply uncertainty in differential diagnoses. Although there is a growing body of literature on the DSM-5 dimensional model of personality disorder, its discriminative features between these clinical samples are still understudied. In this study, we seek to identify the best set of predictors that differentiate between borderline PD and bipolar spectrum, based on pathological and normative personality traits and symptoms. Methods. A cross-sectional study of three clinical samples: 1) Borderline PD group of 63 participants; 2) Major depressive disorder group of 89 participants; 3) Bipolar disorder group of 65 participants. Self-reported assessment: Personality Inventory for DSM-5; Brief Symptom Inventory; FFM Inventory. A series of one-way ANOVAs and logistic regression analyses were computed. Results. The major set of data emerging as common discriminants of borderline PD across the bipolar spectrum are unusual beliefs & experiences, paranoid ideation, obsession-compulsion and extraversion. Depressivity (OR: 34.95) and impulsivity (OR: 22.35) pathological traits displayed the greatest predictive values in the differential diagnosis. Limitations. The small size of the samples; a lack of data from participants’ previous clinical history. Conclusions. Findings support the DSM-5 pathological traits as differentiating borderline PD through bipolar spectrum, and reinforcing the joint use of symptom-related pathological functioning and normal-range personality traits. Alongside the bipolar spectrum, borderline pathology sheds light upon a hypothetical overlap along the depressive and schizoaffective/schizophrenia spectra, representing a borderland space at a crossroads with the psychopathology of a meta-spectrum.

Introduction

State-of-the-art research highlights that borderline personality disorder (PD) and bipolar spectrum disorders have clinical characteristics in common, which imply uncertainty in differential diagnoses (Bayes and Parker, 2020; Bennazi, 2007; Luty, 2020; Paris, 2017). Although there is a growing body of literature on the DSM-5 dimensional model of personality disorder (American Psychiatric Association [APA], 2013; Gore and Widiger, 2013; Krueger and Eaton, 2010; Zimmermann et al., 2019), its discriminative features between borderline PD and both major depressive disorder and bipolar disorder, are still understudied.

The relationship between borderline PD and bipolar spectrum is a complex topic of great theoretical, clinical and public health significance (Akiskal, 2004; Zimmerman et al., 2020). If on the one hand, the precise relationship of personality disorders with the disease spectra is uncertain and an unsolved general problem of psychiatric classification (Angst, 2007; Sperandeo et al., 2020), on the other, a growing body of evidence suggests high comorbidity between personality disorders and bipolar spectrum disorders and draws attention to the important role that personality disorders may play (Ng et al., 2017).

Considerable controversy has arisen around the construct of bipolar spectrum disorders, however the concept may be inferred from numerous classical sources, dating back to the 19th century and even as far back as antiquity (Pies, 2007). Current clinical and epidemiological research provides support for a continuum of bipolar psychopathology, in other words, a bipolar spectrum ranging from subthreshold characteristics to clinical disorders (Walsh et al., 2015). Over the past decades, manifold lines of evidence have raised the controversial question of whether borderline PD is an independent disease entity or if it might be better conceptualized as belonging to the spectrum of mood disorders (Akiskal, 2004; Angst, 2007; Cattaneo et al., 2019; Deltito et al., 2001; Paris, 2009; Perugi et al., 2011).

Differentiating between borderline PD and comorbid major depressive disorder, atypical depression and bipolar disorders is a complex task (Gunderson et al., 2018; MacKinnon and Pies, 2006; Perugi et al., 2011; Ruggero et al., 2010; Zimmerman et al., 2020). Hence, establishing an accurate diagnosis presents a considerable challenge to both research and clinical contexts (Youngstrom et al., 2018). One of the main issues is understanding what comprises borderline PD, since the ambiguity of the term ‘borderline’ acts largely as a fall-back option until the core psychopathology has been successfully identified (Gunderson et al., 2018). A comprehensive quantitative assessment of the overlapping and differential clinical moderators is also warranted in order to better understand the actual boundaries of borderline PD and bipolar disorders (Fornaro et al., 2016). Recent studies have highlighted personality features, relationship style and phenomenological differences in mood states as key differentiating factors, among others (Bayes et al., 2019).

In light of the empirical evidence supporting the DSM-5 dimensional model of personality disorders, which are likewise aligned with the general Five-Factor Model (FFM), the borderline PD traits of emotional lability, anxiousness, separation insecurity, hostility, depressivity, impulsivity, and risk taking have been advanced as core features of the disorder (APA, 2013; Samuel et al., 2012), and as evidence for the domains of negative affectivity (Calvo et al., 2016; Fowler et al., 2021) and disinhibition (Calvo et al., 2016). Research has also pointed to a consideration of cognitive and perceptual dysregulation and suspiciousness for inclusion as a representation of the ninth borderline PD symptom criterion (i.e., stress-induced paranoia or dissociation) (Watters et al., 2019). A newfound and innovative study on the topic of borderline-mood spectrum using the Personality Inventory for DSM-5 (PID-5) has suggested the diagnostic accuracy of a borderline PD algorithm in differentiating bipolar disorder (Fowler et al., 2019).

This paper seeks to identify the best set of predictors that differentiate between borderline PD and bipolar spectrum disorders (major depressive and bipolar disorders), based on pathological and normative personality traits and symptoms, as well as including PID-5 items. To our knowledge, this represents a first analysis of the DSM-5 dimensional model of personality disorder to focus on the discriminative features associated with personality-psychopathology data in a simultaneously differential report of these disorders.