Striatal activity in borderline personality disorder with comorbid intermittent explosive disorder: sex differences

Gender differences in borderline personality disorder: a narrative review

Borderline personality disorder (BPD) is a severe and complex mental disorder that traditionally has been found to be more frequent in the female gender in clinical samples. More recently, epidemiological studies have provided conflicting data about the prevalence of borderline disorder in the two genders in community samples. In order to explain this heterogeneity, some authors hypothesized the presence of a bias in the diagnostic criteria thresholds (more prevalent in one gender than another), in the population sampling (community versus clinical), in the instruments of evaluation (clinician versus self-report measures), and in the diagnostic construct of BPD. Beyond the question of the different prevalence of the disorder between genders, the debate remains open as to how personality and clinical characteristics, and attitude toward treatments express themselves in the two genders. This narrative review is aimed to provide an updated overview of the differences among genders in BPD in terms of diagnosis, temperamental and clinical characteristics, comorbidities, findings of neuroimaging, and treatment attitudes. Studies that specifically investigated the gender differences in BPD patients are rather limited. Most of the investigations did not consider gender as a variable or were characterized by a significant imbalance between the two genders (more commonly in favor the female gender). The main results indicated that men were more likely to endorse the criteria "intense and inappropriate anger" and "impulsivity," whereas women endorsed the criteria "chronic feelings of emptiness," "affective instability," and "suicidality/self-harm behaviors." These findings reflect differences in temperament and symptoms of the two genders. Other relevant differences concern pattern of comorbidity, specific neurobiological mechanisms and attitude to treatments. Main limitations were that only one database was searched, time of publications was limited, non-English manuscripts were excluded, and the quality of each paper was not commented.

Neural correlates of aggression in personality disorders from the perspective of DSM-5 maladaptive traits: a systematic review

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published in 2013, includes an alternative model of personality disorders (AMPD) focusing on a maladaptive trait model utilized to diagnose several personality disorders. Borderline personality disorder (BPD) and antisocial personality disorder (ASPD) are two conditions categorized by AMPD that exhibit high rates of violence and aggression. Several of the traits outlined in the AMPD, including hostility, impulsivity, risk-taking, and callousness, have been previously linked to aggression in BPD and ASPD. However, to the best of our knowledge, there has never been a synthesis of neuroimaging studies that have investigated links between these traits and aggression in BPD and ASPD. To overcome this gap, we conducted a systematic review under the PRISMA framework to locate neuroimaging articles published since the release of AMPD linking trait anger/hostility, impulsivity, risk-taking, and callousness to aggression in BPD and ASPD. Key findings included the following: i) anger/hostility, associated with alterations in the interplay between prefrontal and subcortical regions (primarily the amygdala), may be a common factor explaining aggressive reactions to response to interpersonal threat or provocation; ii) alterations of fronto-temporal-limbic regions and serotonergic and endocannabinoid signaling systems may link impulsivity to aggression in BPD and ASPD; iii) weaker cortico-striatal connectivity could relate to greater risk taking and greater proclivity for violence. Insufficient evidence from neuroimaging articles was discerned to describe a relationship between callousness and aggression. Overall, results of this review reveal a relative paucity of neuroimaging studies examining AMPD traits relevant to aggression in BPD and ASPD. In addition to encouraging further investigation of neuroimaging markers of AMPD traits linked to aggression, we recommend multi-methodological designs, including the incorporation of other biomarkers, such as hormones and indices of physiological arousal, to fully expand our understanding of aggression in BPD and ASPD.

Serotonin transporter availability in physically aggressive personality disordered patients: associations with trait and state aggression, and response to fluoxetine

RATIONALE

Characterizing the neuroanatomical basis of serotonergic abnormalities in severe, chronic, impulsive aggression will allow for rational treatment selection, development of novel therapeutics, and biomarkers to identify at-risk individuals.

OBJECTIVES

The aim of this study is to identify associations between regional serotonin transporter (5-HTT) availability and trait and state aggression, as well as response to the anti-aggressive effects of fluoxetine.

METHODS

We examined 5-HTT availability using positron emission tomography (PET) imaging with [¹¹C]DASB in personality disordered patients with current physical intermittent explosive disorder (IED; n = 18), and healthy comparison participants (HC; n = 11), in the anterior cingulate cortex (ACC), amygdala (AMY), ventral striatum (VST), and midbrain (MID). After PET imaging, IED patients were treated with fluoxetine 20 mg daily (n = 9) or placebo (n = 6) for 12 weeks. Trait and state aggression, trait callousness, and childhood trauma were assessed.

RESULTS

In IED patients, trait aggression was positively associated with [¹¹C]DASB binding in the ACC and VST; covarying for trait callousness and childhood trauma enhanced these correlations. Baseline state aggression was positively correlated with ACC [¹¹C]DASB in IED patients. Greater baseline VST [¹¹C]DASB binding predicted greater decreases in state aggression with fluoxetine treatment.

CONCLUSIONS

Consistent with prior reports, ACC 5-HTT is related to trait aggression, and adjusting for factors related to proactive (callousness) and reactive (childhood trauma) aggression subtypes further resolves this relationship. Novel findings of the study include a better understanding of the association between regional 5-HTT availability and state aggression, and the involvement of VST 5-HTT with trait aggression, and with the anti-aggressive effects of fluoxetine.

Sex differences in borderline personality disorder: A scoping review

Borderline Personality Disorder (BPD) is often perceived to be a female-predominant disorder in both research and clinical contexts. Although there is growing recognition of possible sex differences, the current literature remains fragmented and inconclusive. This scoping review aimed to synthesize available research evidence on potential sex differences in BPD. PsycINFO, PubMed, Scopus and Web-of-Science were searched from January 1982 to July 2022 surrounding the key concepts of sex and BPD. Data searching and screening processes followed the Joanna Briggs Institute methodology involving two independent reviewers, and a third reviewer if necessary, and identified 118 papers. Data regarding BPD symptoms, comorbid disorders, developmental factors, biological markers, and treatment were extracted. Data was summarized using the vote counting method or narrative synthesis depending on the availability of literature. Males with BPD were more likely to present externalizing symptoms (e.g., aggressiveness) and comorbid disorders (e.g., substance use), while females with BPD were more likely to present internalizing symptoms (e.g., affective instability) and comorbid disorders (e.g., mood and eating disorders). This review also revealed that substantially more research attention has been given to overall sex differences in baseline BPD symptoms and comorbid disorders. In contrast, there is a dearth of sex-related research pertaining to treatment outcomes, developmental factors, and possible biological markers of BPD. The present scoping review synthesized current studies on sex differences in BPD, with males more likely to present with externalizing symptoms in contrast to females. However, how this might change the prognosis of the disorder or lead to modifications of treatment has not been investigated. Most studies were conducted on western populations, mainly North American (55%) or European (33%), and there is a need for future research to also take into consideration genetic, cultural, and environmental concomitants. As the biological construct of 'sex' was employed in the present review, future research could also investigate the social construct 'gender'. Longitudinal research designs are needed to understand any longer-term sex influence on the course of the disorder.

Visually guided equivalence learning in borderline personality disorder

The hallmark symptoms of borderline personality disorder are maladaptive behavior and impulsive emotional reactions. However, the condition is occasionally associated with cognitive alterations. Recently, it has been found that the function of the basal ganglia and the hippocampi might also be affected. Hence, deterioration in learning and memory processes associated with these structures is expected. Thus, we sought to investigate visually guided associative learning, a type of conditioning associated with the basal ganglia and the hippocampi, in patients suffering from borderline personality disorder. In this study, the modified Rutgers Acquired Equivalence Test was used to assess associative learning in 23 patients and age-, sex-, and educational level-matched controls. The acquisition phase of the test, which is associated primarily with the frontostriatal loops, was altered in patients with borderline personality disorder: the patients exhibited poor performance in terms of building associations. However, the retrieval and generalization functions, which are primarily associated with the hippocampi and the medial temporal lobes, were not affected. These results corroborate that the basal ganglia are affected in borderline personality disorder. However, maintained retrieval and generalization do not support the assumption that the hippocampi are affected too.

Aggression in borderline personality disorder: A systematic review of neuroimaging studies

Aggressive behaviors are prevalent among patients with Borderline Personality Disorder (BPD). Neuroimaging studies have linked aggression in BPD patients to neurochemical, structural, functional, and metabolic alterations in various brain regions, especially in frontal-limbic areas. This systematic review summarizes current neuroimaging results on aggression among BPD patients and provides an overview of relevant brain mechanisms. A systematic search of PubMed and Web of Science databases, in addition to manual check of references, identified thirty-two eligible articles, including two magnetic resonance spectrum (MRS), thirteen structural magnetic resonance imaging (sMRI), six functional magnetic resonance imaging (fMRI), and eleven positron emission tomography (PET) studies. The reviewed studies have highlighted the abnormalities in prefrontal cortices and limbic structures including amygdala and hippocampus. Less studies have zoomed in the roles of parietal and temporal regions or taken a network perspective. Connectivity studies have shed light on the importance of the frontal-limbic interactions in regulating aggression. Conflicted findings might be attributed to disparity in controlling gender, anatomical subdivisions, and comorbidities, which shall be considered in future studies.

Borderline personality disorder and its symptom clusters: A review of positron emission tomography and single photon emission computed tomography studies

Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are two neuroimaging techniques that have led to important insights into the pathophysiology of borderline personality disorder (BPD) and its symptom clusters. This paper provides the most up-to-date review of PET and SPECT studies targeting BPD. A systematic search of PET and SPECT studies using the databases PsycINFO, PubMed, and Embase was implemented, which yielded 30 articles in the end. Earlier PET studies largely reported decreased glucose metabolism in prefrontal brain regions. More recent PET research has pointed to alterations in monoaminergic systems, greater activation of the opioid system during sadness induction, as well as abnormalities of the brain endocannabinoid system in BPD. SPECT studies of BPD mainly identified changes in regional cerebral blood flow and alterations of the serotonergic system. Such PET and SPECT study abnormalities have been suggested to relate to the symptomatology of BPD, including impulsivity, aggression, and mood changes. The implications of these neuroimaging studies in terms of shedding new light on the pathophysiology of BPD and providing new avenues for drug development are discussed.

Differential effects of the menstrual cycle on reactive and proactive aggression in borderline personality disorder

Borderline personality disorder (BPD) is characterized by rapidly shifting symptoms, including intense anger and aggressive behavior. Understanding how fluctuations in ovarian hormones across the menstrual cycle may contribute to symptom instability is key for accurate assessment of BPD symptoms and effective interventions. Reactive and proactive aggression, as well as anger-in and anger-out, were assessed daily in 15 physically healthy, unmedicated naturally cycling female individuals meeting criteria for BPD across 35 days. Urine luteinizing hormone surge and salivary progesterone were used to confirm ovulation and verify the cycle phase. Multilevel models evaluated cyclical differences of symptoms between cycle phases. Both forms of aggressive behavior demonstrated marked cycle effects, with reactive aggression highest during the midluteal cycle phase, co-occurring with initial increases in anger and irritability and followed by perimenstrual peaks in anger and anger-in. In contrast, highest levels of proactive aggression were observed during the follicular and ovulatory phases, when emotional symptoms and anger were otherwise at lowest levels. These findings highlight the importance of identifying the function of aggression when considering potential psychological and biological influences. Naturally cycling individuals with BPD may be at elevated risk for luteal worsening of a range of interpersonally reactive symptoms, including reactive aggression, whereas proactive aggression may occur more in phases characterized by less emotional and cognitive vulnerability and greater reward sensitivity. Research on aggression in this population should consider cycle effects. Cycling individuals with BPD attempting to reduce aggressive behavior may benefit from cycle-tracking to increase awareness of these effects and to develop appropriate strategies.

Single-Photon Emission Computed Tomography and Positron Emission Tomography Studies of Antisocial Personality Disorder and Aggression: a Targeted Review

PURPOSE OF REVIEW

This paper aims to provide a comprehensive discussion of single-photon emission computed tomography (SPECT) and positron emission tomography (PET) studies of antisocial personality disorder (ASPD) and aggression.

RECENT FINDINGS

Among ASPD males with high impulsivity, the density of brainstem serotonin (5-HT) transporters shows a relationship with impulsivity, aggression, and ratings of childhood trauma. 5-HT_1B receptor (R) binding in the striatum, anterior cingulate cortex, and orbitofrontal cortex (OFC) correlated with anger, aggression, and psychopathic traits in another study of violent offenders, most of whom were diagnosed with ASPD. Finally, the density of monoamine oxidase-A (MAO-A), a mitochondrial enzyme that degrades 5-HT, norepinephrine, and dopamine (DA), was reported as lower in the OFC and ventral striatum of ASPD. Among non-clinical populations, 5-HT₄R binding, as an index of low cerebral 5-HT levels, has been associated with high trait aggression, but only in males. Furthermore, evidence suggests that individuals with high-activity MAO-A genetic variants compared with low-activity MAO-A allelic variants release more DA in the ventral caudate and putamen when exposed to violent imagery. There are very few PET or SPECT studies that exclusively sample individuals with ASPD. However, among ASPD samples, there is evidence of regional serotonergic abnormalities in the brain and alteration of neural MAO-A levels. Future studies should consider employing additional molecular probes that could target alternative neurotransmitter systems to investigate ASPD. Furthermore, examining different typologies of aggression in clinical and non-clinical populations using SPECT/PET is another important area to pursue and could shed light on the neurochemical origins of these traits in ASPD.

Past, present, and future of genetic research in borderline personality disorder

Borderline Personality Disorder (BPD) is a major mental illness with a lifetime prevalence of approximately 1-3%, characterized by a persistent pattern of instability in relationships, mood, impulse regulation, and sense of self. This results in impulsive self-damaging behavior, high suicide rates, and severe functional impairment. BPD has a complex, multifactorial etiology, resulting from an interaction among genetic and environmental substrates, and has moderate to high heritability based on twin and family studies. However, our understanding of the genetic architecture of BPD is very limited. This is a critical obstacle since genetics can pave the way for identifying new treatment targets and developing preventive and disease-modifying pharmacological treatments which are currently lacking. We review genetic studies in BPD, with a focus on limitations and challenges and future directions. Genetic research in BPD is still in its very early stages compared to other major psychiatric disorders. Most early genetic studies in BPD were non-replicated association studies in small samples, focused on single candidate genes. More recently, there has been one genome-wide linkage study and a genome-wide association study (GWAS) of subclinical BPD traits and a first GWAS in a relatively modest sample of patients fulfilling full diagnostic criteria for the disorder. Although there are adequate animal models for some of the core dimensions of BPD, there is a lack of translational research including data from animal models in BPD. Research in more pioneering fields, such as imaging genetics, deep sequencing and epigenetics, holds promise for elucidating the pathophysiology of BPD and identifying new treatment targets.

A neurochemical hypothesis for the origin of hominids

It has always been difficult to account for the evolution of certain human characters such as language, empathy, and altruism via individual reproductive success. However, the striatum, a subcortical region originally thought to be exclusively motor, is now known to contribute to social behaviors and "personality styles" that may link such complexities with natural selection. We here report that the human striatum exhibits a unique neurochemical profile that differs dramatically from those of other primates. The human signature of elevated striatal dopamine, serotonin, and neuropeptide Y, coupled with lowered acetylcholine, systematically favors externally driven behavior and greatly amplifies sensitivity to social cues that promote social conformity, empathy, and altruism. We propose that selection induced an initial form of this profile in early hominids, which increased their affiliative behavior, and that this shift either preceded or accompanied the adoption of bipedality and elimination of the sectorial canine. We further hypothesize that these changes were critical for increased individual fitness and promoted the adoption of social monogamy, which progressively increased cooperation as well as a dependence on tradition-based cultural transmission. These eventually facilitated the acquisition of language by elevating the reproductive advantage afforded those most sensitive to social cues.

Brain Mechanisms Underlying Reactive Aggression in Borderline Personality Disorder-Sex Matters

BACKGROUND

Aggression in borderline personality disorder (BPD) is thought to be mediated through emotion dysregulation via high trait anger. Until now, data comparing anger and aggression in female and male patients with BPD have been widely missing on the behavioral and particularly the brain levels.

METHODS

Thirty-three female and 23 male patients with BPD and 30 healthy women and 26 healthy men participated in this functional magnetic resonance imaging study. We used a script-driven imagery task consisting of narratives of both interpersonal rejection and directing physical aggression toward others.

RESULTS

While imagining both interpersonal rejection and acting out aggressively, a sex × group interaction was found in which male BPD patients revealed higher activity in the left amygdala than female patients. In the aggression phase, men with BPD exhibited higher activity in the lateral orbitofrontal and dorsolateral prefrontal cortices compared with healthy men and female patients. Positive connectivity between amygdala and posterior middle cingulate cortex was found in female patients but negative connectivity was found in male patients with BPD. Negative modulatory effects of trait anger on amygdala-dorsolateral prefrontal cortex and amygdala-lateral orbitofrontal cortex coupling were shown in male BPD patients, while in female patients trait anger positively modulated dorsolateral prefrontal cortex-amygdala coupling. Trait aggression was found to positively modulate connectivity of the left amygdala to the posterior thalamus in male but not female patients.

CONCLUSIONS

Data suggest poor top-down adjustment of behavior in male patients with BPD despite their efforts at control. Female patients appear to be less aroused through rejection and to successfully dampen aggressive tension during the imagination of aggressive behavior.

Review on Neural Correlates of Emotion Regulation and Music: Implications for Emotion Dysregulation

Previous studies have examined the neural correlates of emotion regulation and the neural changes that are evoked by music exposure. However, the link between music and emotion regulation is poorly understood. The objectives of this review are to (1) synthesize what is known about the neural correlates of emotion regulation and music-evoked emotions, and (2) consider the possibility of therapeutic effects of music on emotion dysregulation. Music-evoked emotions can modulate activities in both cortical and subcortical systems, and across cortical-subcortical networks. Functions within these networks are integral to generation and regulation of emotions. Since dysfunction in these networks are observed in numerous psychiatric disorders, a better understanding of neural correlates of music exposure may lead to more systematic and effective use of music therapy in emotion dysregulation.

Amygdala and dlPFC abnormalities, with aberrant connectivity and habituation in response to emotional stimuli in females with BPD

BACKGROUND

Little is known about the frontolimbic abnormalities thought to underlie borderline personality disorder (BPD). We endeavoured to study regional responses, as well as their connectivity and habituation during emotion processing.

METHODS

14 BPD patients and 14 normal female controls (NC) controlled for menstrual phase underwent emotion-induction during an fMRI task using standardised images in a block design. We then performed psychophysiological interaction (PPI) analysis to investigate functional connectivity.

RESULTS

BPD patients reported more disgust in questionnaires compared to controls. Relative to NC, they showed reduced left amygdala and increased dorsolateral prefrontal cortex (dlPFC) activation to all emotions collapsed versus neutral. Habituation of ventral striatal activity to repeated emotional stimuli was observed in controls but not in BPD. Finally, in the context of disgust (but not other emotions) versus neutral, BPD patients displayed enhanced left amygdala coupling with the dlPFC and ventral striatum.

LIMITATIONS

Strict inclusion criteria reduced the sample size.

CONCLUSIONS

In summary, BPD showed abnormal patterns of activation, habituation and connectivity in regions linked to emotion regulation. Amygdala deactivation may be mediated by abnormal top-down regulatory control from the dorsolateral prefrontal cortex. Aberrant emotion processing may play a unique role in the pathophysiology of BPD.

Anger and aggression in borderline personality disorder and attention deficit hyperactivity disorder - does stress matter?

BACKGROUND

The impact of stress on anger and aggression in Borderline Personality Disorder (BPD) and Attention Deficit Hyperactivity Disorder (ADHD) has not been thoroughly investigated. The goal of this study was to investigate different aspects of anger and aggression in patients with these disorders.

METHODS

Twenty-nine unmedicated female BPD patients, 28 ADHD patients and 30 healthy controls (HC) completed self-reports measuring trait anger, aggression and emotion regulation capacities. A modified version of the Point Subtraction Aggression Paradigm and a state anger measurement were applied under resting and stress conditions. Stress was induced by the Mannheim Multicomponent Stress Test (MMST).

RESULTS

Both patient groups scored significantly higher on all self-report measures compared to HCs. Compared to ADHD patients, BPD patients reported higher trait aggression and hostility, a stronger tendency to express anger when provoked and to direct anger inwardly. Furthermore, BPD patients exhibited higher state anger than HCs and ADHD patients under both conditions and showed a stress-dependent anger increase. At the behavioral level, no significant effects were found. In BPD patients, aggression and anger were positively correlated with emotion regulation deficits.

CONCLUSIONS

Our findings suggest a significant impact of stress on self-perceived state anger in BPD patients but not on aggressive behavior towards others in females with BPD or ADHD. However, it appears to be pronounced inwardly directed anger which is of clinical importance in BPD patients.

White Matter Integrity Reductions in Intermittent Explosive Disorder

Intermittent explosive disorder (IED), as described in DSM-5, is the categorical expression of pathological impulsive aggression. Previous work has identified neurobiological correlates of the disorder in patterns of frontal-limbic brain activity and dysregulation of serotonergic neurotransmission. Given the importance of short- and-long range white matter connections of the brain in social and emotional behavior, studies of white matter connectivity in impulsive aggression are warranted. Diffusion tensor imaging (DTI) studies in the related conditions of antisocial and borderline personality disorder have produced preliminary evidence of disturbed white matter connectivity in these disorders, but to date there have been no DTI studies in IED. A total of 132 male and female adults between the ages of 18 and 55 years underwent Turboprop-DTI on a 3-Tesla MRI scanner. Of these, 42 subjects had IED, 40 were normal controls, and 50 were clinical psychiatric controls with psychiatric disorders without IED. All subjects were free of alcohol, psychotropic medications, or drugs of abuse. The diffusion tensor was calculated in each voxel and maps of fractional anisotropy (FA) were generated. Tract-based spatial statistics (TBSS) were used to compare FA along the white matter skeleton among the three subject groups. IED was associated with lower FA in two clusters located in the superior longitudinal fasciculus (SLF) when compared with the psychiatric and healthy controls. Impulsive aggression and borderline personality disorder, but not psychopathy or antisocial personality disorder, was associated with lower FA in the two clusters within the SLF. In conclusion, IED was associated with lower white matter integrity in long-range connections between the frontal and temporoparietal regions.

Reward vs. Retaliation-the Role of the Mesocorticolimbic Salience Network in Human Reactive Aggression

The propensity for reactive aggression (RA) which occurs in response to provocation has been linked to hyperresponsivity of the mesocorticolimbic reward network in healthy adults. Here, we aim to elucidate the role of the mesocorticolimbic network in clinically significant RA for two competing motivated behaviors, reward-seeking vs. retaliation. 18 male participants performed a variant of the Point-Subtraction Aggression Paradigm (PSAP) during functional magnetic resonance imaging (fMRI). We examined whether RA participants compared with non-aggressive controls would choose to obtain a monetary reward over the opportunity to retaliate against a fictitious opponent, who provoked the participant by randomly stealing money from his earnings. Across all fMRI-PSAP runs, RA individuals vs. controls chose to work harder to earn money but not to retaliate. When engaging in such reward-seeking behavior vs. retaliation in a single fMRI-PSAP run, RA individuals exhibited increased activation in the insular-striatal part of the mesocorticolimbic salience network, and decreased precuneus and ventromedial prefrontal cortex activation compared to controls. Enhanced overall reward-seeking behavior along with an up-regulation of the mesocorticolimbic salience network and a down-regulation of the default-mode network in RA individuals indicate that RA individuals are willing to work more for monetary reward than for retaliation when presented with a choice. Our findings may suggest that the use of positive reinforcement might represent an efficacious intervention approach for the potential reduction of retaliatory behavior in clinically significant RA.

Neurobiological and behavioural studies of affective instability in clinical populations: a systematic review

OBJECTIVES

To evaluate the neurobiological, psychophysical and behavioural measures of affective instability in clinical populations.

DATA SOURCES

A range of medical and psychological science electronic databases were searched (including MEDLINE, EMBASE, and PsycINFO). Hand searching and reference checking are also included.

REVIEW METHODS

Reviews, systematic reviews, experimental and cross-sectional studies, providing affective instability in neurobiological and behavioural measurements in clinical populations. Studies were selected, data were extracted and quality was appraised.

RESULTS

Twenty-nine studies were included, 6 of which were review studies (one a meta-analysis) and 23 of which were primary studies, across a wide variety of disorders including ADHD, bipolar affective disorder, schizophrenia, severe mood dysregulation, major depression, and borderline personality disorder.

CONCLUSIONS

The bulk of the studies converge on the role of the amygdala, particularly in borderline personality disorders, and how it connects with other areas of the brain. Future research needs to extend these findings across diagnoses and development.

Gender differences in aggression of borderline personality disorder

Aggression is a core feature of borderline personality disorder (BPD). Well-replicated results from the general population indicate that men engage in aggression more frequently than women. This article addresses the question of whether gender also influences aggression in BPD, and whether the neurobiological mechanisms underlying aggressive behavior differ between male and female BPD patients. Data show that most self-reports, interviews and behavioral tasks investigating samples of BPD patients do not find enhanced aggressiveness in male patients, suggesting that BPD attenuates rather than aggravates gender differences usually present in the general population. Neurobiological studies comparing BPD patients with gender-matched healthy controls, however, reveal a number of interesting gender differences: On the one hand, there are well-replicated findings of reduced amygdala and hippocampal gray matter volumes in female BPD patients, while these findings are not shared by male patients with BPD. On the other hand, only male BPD patients exhibit reduced gray matter volume of the anterior cingulate cortex, increased gray matter volume of the putamen, reduced striatal activity during an aggression task, and a more pronounced deficit in central serotonergic responsivity. These neurobiological findings point to a particular importance of impulsivity for the aggression of male BPD patients. Limitations include the need to control for confounding influences of comorbidities, particularly as male BPD patients have been consistently found to show higher percentages of aggression-predisposing comorbid disorders, such as antisocial personality disorder, than female BPD patients. In the future, studies which include systematic comparisons between females and males are warranted in order to disentangle gender differences in aggression of BPD patients with the aim of establishing gender-sensitive treatments where needed.

Examining sex differences in DSM-IV borderline personality disorder symptom expression using Item Response Theory (IRT)

Limited literature suggests that there may be differences in how women and men experience borderline personality disorder (BPD) symptoms. The aim of the current study was to use methods based on item response theory (IRT) to examine whether, when equating for levels of BPD symptom severity, there are sex differences in the likelihood of reporting DSM-IV BPD symptoms. We conducted these analyses using a large, nationally representative sample from the USA (n = 34,653), the second wave of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Data from women and men were compared. There were statistically and clinically significant sex differences for 3 out of the 9 DSM-IV BPD symptoms. We found that women were more likely to experience suicidal/self-mutilation behavior, affective instability and chronic feelings of emptiness and tended to be less likely to endorse impulsivity at lower levels of borderline personality disorder severity than men, while affective instability and chronic feelings of emptiness appeared to be significantly less discriminant in terms of severity in men than in women. There were no significant differences between women and men on the remaining DSM-IV symptoms. Overall, our findings indicate substantial sex differences in borderline personality disorder symptom expression. Although our results may reflect sex-bias in diagnostic criteria, they are in keeping with recent arguments suggesting that BPD could be understood as a clinical phenomenon that may partially differ in men and women.

Serotonin transporter availability in impulsive aggressive personality disordered patients: a PET study with [11C]DASB

Serotonin (5-HT) has consistently been implicated in the pathophysiology of impulsive aggression. In the current study, we tested the hypothesis that 5-HT transporter (5-HTT) binding is reduced in the anterior cingulate cortex (ACC) in impulsive aggressive patients. Additionally, we characterized pathological personality dimensions, with a specific focus on callousness (i.e. emotional indifference, a facet of psychopathy). Callousness is putatively positively correlated with presynaptic 5-HT, and thus could potentially confound the hypothesized negative relation between 5-HTT levels and trait aggression. We determined 5-HTT binding with positron emission tomography and [(11)C]DASB in 29 patients with intermittent explosive disorder (IED-IR) and 30 controls. We assessed group differences in 5-HTT binding in the pregenual ACC, amygdala and subcortical regions and examined correlations between 5-HTT binding and clinical measures. There were no significant differences in 5-HTT binding between IED-IR patients and controls. Trait callousness exhibited a significant, positive correlation with ACC 5-HTT availability. Among IED-IR patients, a trend-level negative partial correlation was observed between trait aggression and ACC 5-HTT availability, while covarying for callousness and age. Exploratory analyses revealed a significant negative correlation between state aggression levels and 5-HTT availability in subcortical regions, namely striatum and thalamus. We did not confirm our hypothesis of lower ACC 5-HTT availability in impulsive aggressive patients, however, the positive correlation between callousness and ACC 5-HTT availability likely played a confounding role. Subtypes of aggression (e.g., reactive vs. proactive aggression), which are differentially associated with pathological personality dimensions such as callousness, may contribute to variability between 5-HT functioning and aggression.

The latest neuroimaging findings in borderline personality disorder

Borderline personality disorder (BPD) is a severe mental disorder, characterized by pronounced deficits in emotion regulation, cognitive disturbances including dissociation, impulsivity, and interpersonal disturbances. Over the last decades, neuroimaging has become one of the most important methods to investigate neurobiological alterations possibly underlying core features of BPD. The aim of our article is to provide an overview of the latest neuroimaging research in BPD focusing on functional and structural MRI studies published since 2010. Findings of these studies are depicted and discussed referring to central domains of BPD psychopathology. On a neurochemical level, altered function in neurotransmitter systems including the serotonin, glutamate, and GABA systems was observed in patients with BPD. On a neural level, individuals with BPD showed structural and functional abnormalities in a fronto-limbic network including regions involved in emotion processing (e.g., amygdala, insula) and frontal brain regions implicated in regulatory control processes (e.g., anterior cingulate cortex, medial frontal cortex, orbitofrontal cortex, and dorsolateral prefrontal cortex). Limbic hyperreactivity and diminished recruitment of frontal brain regions may yield a link between disturbed emotion processing and other core features of BPD such as impulsivity and interpersonal disturbances. To clarify whether findings are specific to BPD, comparisons with other clinical groups are needed.

Structure of genetic and environmental risk factors for symptoms of DSM-IV borderline personality disorder

IMPORTANCE

Previous studies have indicated that the psychopathological dimensions of borderline personality disorder (BPD) are influenced by a unitary liability factor. However, to our knowledge, the underlying etiological nature of the individual criteria for BPD as defined by the DSM-IV has not been explored.

OBJECTIVE

To determine the structure of genetic and environmental risk factors for the symptoms of BPD.

DESIGN, SETTING, AND PARTICIPANTS

Multivariate twin study with BPD criteria assessed by personal interview within a general community setting. Participants included 2794 young adults from the Norwegian Institute of Public Health Twin Panel.

MAIN OUTCOMES AND MEASURES

The 9 criteria for BPD assessed by the Structured Interview for DSM-IV Personality.

RESULTS

A common pathway model dominated by 1 highly heritable (55%) general BPD factor that strongly influenced all 9 BPD criteria (standardized path coefficients, 0.53-0.79) fit the data best. The model also included 2 additional common liability factors, mainly influencing criteria reflecting the affective and interpersonal dimensions. Both of these were mostly influenced by environmental liability factors (heritability, 29.3% and 2.2%). With 1 exception (criterion 2, unstable and intense relationships), the specific criteria were strongly influenced by environmental factors. Five of the 9 criterion-specific genetic effects were either 0 or negligible.

CONCLUSIONS AND RELEVANCE

These results indicate that most of the genetic effects on the individual BPD criteria derive from 1 highly heritable general BPD factor, whereas the environmental influences were mostly criterion specific.