Neurotransmitter dysfunction in patients with borderline personality disorder

The borderline diagnosis III: identifying endophenotypes for genetic studies

Although it is generally acknowledged that borderline personality disorder (BPD) has a complex, multifactorial etiology with interacting genetic and environmental substrates, the specific genetic underpinnings of this disorder have not been extensively investigated. Family aggregation studies suggest the heritability for BPD as a diagnosis, but the genetic basis for this disorder may be stronger for dimensions such as impulsivity/aggression and affective instability than for the diagnostic criteria itself. Family, adoptive, and twin studies also converge to support an underlying genetic component to the disorder. An endophenotypic approach to defining the genetics of this complex disorder may be called for. Twin studies in an epidemiologic, non-clinically ascertained sample using both diagnostic measures and laboratory measures that can be operationalized, including neuropsychologic, psychophysiologic, and operationalized behavioral tests, may be useful. Large-scale family studies of clinically ascertained samples with careful diagnostic demarcation and measurement of endophenotypes in probands and relatives may also prove to be a promising approach. The use of laboratory paradigms for measures of aggression and affective instability are discussed in the context of such endophenotypic approaches.

The neurobiology of borderline personality disorder: the synergy of "nature and nurture"

The author reviews the current state of our knowledge concerning the neurobiology of borderline personality disorder (BPD). A converging body of scientific evidence indicates that patients with BPD suffer from impairments in the brain systems that regulate impulsivity, aggression, and affect. This article reviews data on the neurobiology of the symptoms of BPD, including emotional and behavioral dysregulation, identity disturbance, cognitive impairments, and interpersonal difficulties. The author first considers the evolutionary context in which BPD can develop to put the neurobiological findings in perspective, and then discusses the roles of both genetic inheritance and the environment in the development of BPD. The role of neurotransmitter systems in the development of impulsive-aggression and affective instability is reviewed. Possible neurobiological contributors to the identity disturbance seen in BPD are also described. The author then considers environmental contributions to BPD and discusses the synergy of nature and nurture in the development of BPD symptoms. Findings concerning the types of neurobiological impairments that can arise as a result of childhood neglect and abuse and other types of chronic severe stress and trauma are discussed. Finally, the author reviews studies of animal attachment models that suggest that types of maternal care can produce lifelong behavioral and physiological differences in offspring and that this effect is mediated through the regulation of gene expression. The author suggests that the large body of neuroscience research reviewed in this article suggests that, while patients with BPD may be born with innate genetic tendencies for impaired brain systems for regulating impulses and affect, the environment they find themselves born into may be critical in determining whether or not they develop the full blown syndrome of BPD.

Affective instability and impulsivity in borderline personality and bipolar II disorders: similarities and differences

OBJECTIVES

many studies have reported a high degree of comorbidity between mood disorders, among which are bipolar disorders, and borderline personality disorder and some studies have suggested that these disorders are co-transmitted in families. However, few studies have compared personality traits between these disorders to determine whether there is a dimensional overlap between the two diagnoses. The aim of this study was to compare impulsivity, affective lability and intensity in patients with borderline personality and bipolar II disorder and in subjects with neither of these diagnoses.

METHODS

patients with borderline personality but without bipolar disorder (n=29), patients with bipolar II disorder without borderline personality but with other personality disorders (n=14), patients with both borderline personality and bipolar II disorder (n=12), and patients with neither borderline personality nor bipolar disorder but other personality disorders (OPD; n=93) were assessed using the Affective Lability Scale (ALS), the Affect Intensity Measure (AIM), the Buss-Durkee Hostility Inventory (BDHI) and the Barratt Impulsiveness Scale (BIS-7B).

RESULTS

borderline personality patients had significantly higher ALS total scores (P<0.05) and bipolar II patients tended to have higher ALS scores than patients with OPD (P<0.06). On one of the ALS subscales, the borderline patients displayed significant higher affective lability between euthymia and anger (P<0.002), whereas patients with bipolar II disorder displayed affective lability between euthymia and depression (P<0.04), or elation (P<0.01) or between depression and elation (P<0.01). A significant interaction between borderline personality and bipolar II disorder was observed for lability between anxiety and depression (P<0.01) with the ALS. High scores for impulsiveness (BISTOT, P<0.001) and hostility (BDHI, P<0.05) were obtained for borderline personality patients only and no significant interactions between diagnoses were observed. Only borderline personality patients tended to have higher affective intensity (AIM, P<0.07).

CONCLUSIONS

borderline personality disorder and bipolar II disorder appear to involve affective lability, which may account for the efficacy of mood stabilizers treatments in both disorders. However, our results suggest that borderline personality disorder cannot be viewed as an attenuated group of affective disorders.

Structural relations between borderline personality disorder features and putative etiological correlates

This study assessed the structural relations between borderline personality disorder (BPD) features and purported etiological correlates. Approximately 5,000 18-year-old nonclinical young adults were screened for BPD features, and 2 cohorts of participants (total N = 421; approximately one half of whom endorsed significant borderline features) completed the laboratory phase of the study. Measures included self-report and interview-based assessments of BPD psychopathology, personality, psychopathology in biological parents, and childhood physical and sexual abuse. Significant relations between BPD features and purported etiological correlates of BPD were found. A multivariate model that included parental psychopathology, childhood abuse, and personality factors provided an adequate fit to the data and supported the contention that the personality traits disinhibition and negative affectivity underlie BPD features.