Hippocampal volume reduction and history of aggressive behaviour in patients with borderline personality disorder

Distinct patterns of hippocampal subfield volumes predict coping strategies, emotion regulation, and impulsivity in healthy adults

BACKGROUND

Recent studies have suggested that the hippocampus (HC) is involved in cognitive and behavioral functions beyond memory. We aimed to investigate how the volume of each subfield of the HC is associated with distinct patterns of coping strategies, emotion regulation, and impulsivity in a healthy population.

METHODS

We studied a total of 218 healthy subjects using the Leipzig mind-brain-body dataset. Participants were assessed for coping strategies, emotion regulation, and impulsivity using the Cognitive Emotion Regulation Questionnaire (CERQ), Coping Orientations to Problems Experienced (COPE), Impulsive Behavior Scale (UPPS), and Behavioral Activation and Inhibition System (BAS/BIS). The associations between HC subfield volumes including CA1, CA2/3, CA4/DG, SR-SL-SM, and subiculum, and behavioral scores were examined using multiple linear regression models adjusted for possible confounders, including age, sex, years of education, handedness, total intracranial volume (ICV), and HC volume.

RESULTS

The use of emotional support, venting, and positive reframing coping strategies were significantly and positively correlated with total, total right, and total left HC volumes. Venting was significantly associated with CA1 after adjusting for age, sex, handedness, and education (P=0.001, B = 0.265, P-FDR = 0.005). No significant association was observed between CERQ subscales and HC subfield volumes after controlling for confounders and multiple analyses. However, sensation-seeking subscale of the UPPS-P was positively correlated with total and right CA2-CA3 volumes after adjustments for age, sex, handedness, ICV, and HC volumes (P=0.002, B = 0.266, P-FDR = 0.035). BAS and BIS subscales did not show significant relationship with HC subfield volumes.

CONCLUSION

Patterns of HC subfields volumes are associated with coping strategies, impulsivity, and emotion regulation. In particular, using emotional support, positive reframing, venting, and sensation seeking are significantly associated with certain HC subfield volumes. These findings suggest that the hippocampus may play a crucial role in modulating emotional responses and behavioral adaptations, offering potential targets for therapeutic interventions.

Aberrant glutamatergic systems underlying impulsive behaviors: Insights from clinical and preclinical research

Impulsivity is a broad construct that often refers to one of several distinct behaviors and can be measured with self-report questionnaires and behavioral paradigms. Several psychiatric conditions are characterized by one or more forms of impulsive behavior, most notably the impulsive/hyperactive subtype of attention-deficit/hyperactivity disorder (ADHD), mood disorders, and substance use disorders. Monoaminergic neurotransmitters are known to mediate impulsive behaviors and are implicated in various psychiatric conditions. However, growing evidence suggests that glutamate, the major excitatory neurotransmitter of the mammalian brain, regulates important functions that become dysregulated in conditions like ADHD. The purpose of the current review is to discuss clinical and preclinical evidence linking glutamate to separate aspects of impulsivity, specifically motor impulsivity, impulsive choice, and affective impulsivity. Hyperactive glutamatergic activity in the corticostriatal and the cerebro-cerebellar pathways are major determinants of motor impulsivity. Conversely, hypoactive glutamatergic activity in frontal cortical areas and hippocampus and hyperactive glutamatergic activity in anterior cingulate cortex and nucleus accumbens mediate impulsive choice. Affective impulsivity is controlled by similar glutamatergic dysfunction observed for motor impulsivity, except a hyperactive limbic system is also involved. Loss of glutamate homeostasis in prefrontal and nucleus accumbens may contribute to motor impulsivity/affective impulsivity and impulsive choice, respectively. These results are important as they can lead to novel treatments for those with a condition characterized by increased impulsivity that are resistant to conventional treatments.

Maternal separation in mice leads to anxiety-like/aggressive behavior and increases immunoreactivity for glutamic acid decarboxylase and parvalbumin in the adolescence ventral hippocampus

It has been reported that stressful events in early life influence behavior in adulthood and are associated with different psychiatric disorders, such as major depression, post-traumatic stress disorder, bipolar disorder, and anxiety disorder. Maternal separation (MS) is a representative animal model for reproducing childhood stress. It is used as an animal model for depression, and has well-known effects, such as increasing anxiety behavior and causing abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis. This study investigated the effect of MS on anxiety or aggression-like behavior and the number of GABAergic neurons in the hippocampus. Mice were separated from their dams for four hours per day for 19 d from postnatal day two. Elevated plus maze (EPM) test, resident-intruder (RI) test, and counted glutamic acid decarboxylase 67 (GAD67) or parvalbumin (PV) positive cells in the hippocampus were executed using immunohistochemistry. The maternal segregation group exhibited increased anxiety and aggression in the EPM test and the RI test. GAD67-positive neurons were increased in the hippocampal regions we observed: dentate gyrus (DG), CA3, CA1, subiculum, presubiculum, and parasubiculum. PV-positive neurons were increased in the DG, CA3, presubiculum, and parasubiculum. Consistent with behavioral changes, corticosterone was increased in the MS group, suggesting that the behavioral changes induced by MS were expressed through the effect on the HPA axis. Altogether, MS alters anxiety and aggression levels, possibly through alteration of cytoarchitecture and output of the ventral hippocampus that induces the dysfunction of the HPA axis.

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.

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.

Association of subcortical gray-matter volumes with life-course-persistent antisocial behavior in a population-representative longitudinal birth cohort

Neuropsychological evidence supports the developmental taxonomy theory of antisocial behavior, suggesting that abnormal brain development distinguishes life-course-persistent from adolescence-limited antisocial behavior. Recent neuroimaging work confirmed that prospectively-measured life-course-persistent antisocial behavior is associated with differences in cortical brain structure. Whether this extends to subcortical brain structures remains uninvestigated. This study compared subcortical gray-matter volumes between 672 members of the Dunedin Study previously defined as exhibiting life-course-persistent, adolescence-limited or low-level antisocial behavior based on repeated assessments at ages 7-26 years. Gray-matter volumes of 10 subcortical structures were compared across groups. The life-course-persistent group had lower volumes of amygdala, brain stem, cerebellum, hippocampus, pallidum, thalamus, and ventral diencephalon compared to the low-antisocial group. Differences between life-course-persistent and adolescence-limited individuals were comparable in effect size to differences between life-course-persistent and low-antisocial individuals, but were not statistically significant due to less statistical power. Gray-matter volumes in adolescence-limited individuals were near the norm in this population-representative cohort and similar to volumes in low-antisocial individuals. Although this study could not establish causal links between brain volume and antisocial behavior, it constitutes new biological evidence that all people with antisocial behavior are not the same, supporting a need for greater developmental and diagnostic precision in clinical, forensic, and policy-based interventions.

Structural Brain Development and Aggression: A Longitudinal Study in Late Childhood

This longitudinal study examined the neurodevelopmental correlates of aggression in children, focusing on structural brain properties. A community sample of 110 (60 females) children participated at age 8 years and again at age 10 years. Brain structure was assessed by using magnetic resonance imaging (MRI), and parents reported on child aggression using the Child Behavior Checklist. Analyses examined the relationship between aggression and development of volume of subcortical regions, cortical thickness, and subcortical-cortical structural coupling. Females with relatively high aggression exhibited reduced right hippocampal growth over time. Across males and females, aggression was associated with amygdala- and hippocampal-cortical developmental coupling, with findings for amygdala-cortical coupling potentially indicating reduced top-down prefrontal control of the amygdala in those with increasing aggression over time. Findings suggest that aggressive behaviors may be associated with alterations in normative brain development; however, results were not corrected for multiple comparisons and should be interpreted with caution.

Efficacy of Polyunsaturated Fatty Acids (PUFAs) on Impulsive Behaviours and Aggressiveness in Psychiatric Disorders

It is the focus of increasing interest to investigate the effects of long-chain n-3 and long-chain n-6 polyunsaturated fatty acids (LC n-3 PUFAs; LC n-6 PUFAs) on psychiatric symptoms in a transdiagnostic perspective. There is some evidence that low levels of LC n-3 PUFAs and a higher ratio of LC n-6 to LC n-3 PUFAs in plasma and blood cells are associated with aggressive and impulsive behaviours. Therefore, implementation of LC n-3 PUFAs may produce positive effects on hostility, aggression, and impulsivity in both psychiatric and non-psychiatric samples across different stages of life. A possible mechanism of action of LC n-3 PUFAs in conditions characterized by a high level of impulsivity and aggression is due to the effect of these compounds on the serotonin system and membrane stability. Studies that evaluated the effects of LC n-3 PUFAs on impulsivity and aggressiveness indicated that addition of rather low doses of these agents to antipsychotic treatment might reduce agitation and violent behaviours in psychosis, attention deficit hyperactivity disorder, personality disorders, and impulsive control and conduct disorders. The present review is aimed at examining and discussing available data from recent trials on this topic.

Associations between Traumatic Brain Injury, Drug Abuse, Alcohol Use, Adverse Childhood Events, and Aggression Levels in Individuals with Foster Care History

Nearly 50,000 Canadian children live in foster care. Compared with their peers, foster children experience greater independence and decreased guidance, predisposing them to harmful exposures such as traumatic brain injury (TBI), illicit drugs, and alcohol. Foster children also report a higher level of childhood abuse compared with the general population. This study aimed to: 1) investigate substance/alcohol use disorder, adverse childhood events (ACE), TBI, aggression levels, and the difference between normalized percentages of brain regions of interest (ROIs) in a sample of Canadian youths with and without foster care history; 2) determine the prevalence of substance/alcohol use disorder, ACE, and aggression levels within individuals with foster care history when stratified by likelihood of TBI; and 3) determine the significant correlates of elevated aggression levels within this population. Participants completed standardized questionnaires that measured the prevalence of TBI, substance and alcohol use disorder, ACE, and aggression. Magnetic resonance imaging (MRI) was used to measure differences in brain ROI. Regression and network analysis were used to study interactions between variables. Seventy-four participants (51 individuals with foster care history and 23 age-matched controls from the general population) completed standardized questionnaires. Fifty-five of these individuals (39 foster participants and 16 controls) underwent brain MRI. Foster participants had higher prevalence of substance use disorder (p < 0.001), alcohol use disorder (p = 0.003), ACE (p < 0.001), and elevated aggression levels (p < 0.001) than healthy controls. No significant difference was found among brain ROI. The prevalence of TBI in foster participants was 65%. Foster participants with moderate or high likelihood of TBI exposure had higher levels of drug use and aggression than those with no or low likelihood of exposure. Brain volumes were not associated with substance/alcohol use disorder or ACE. No significant associations were found between aggression levels and the studied variables.

Hippocampal volume in borderline personality disorder with and without comorbid posttraumatic stress disorder: A meta-analysis

Background

Several studies have found a reduction in hippocampal volume in borderline personality disorder (BPD) patients.

Methods

In order to investigate the degree to which comorbid posttraumatic stress disorder (PTSD) could account for reduction in hippocampal volume in these patients, we conducted a systematic review and meta-analysis of studies that compared hippocampal volume in BPD patients with and without PTSD relative to healthy controls.

Results

Seven articles, involving 124 patients and 147 controls, were included. We found a statistically significant reduction for the left and right hippocampus. Data from the four studies that discriminated BPD patients with and without PTSD indicate that hippocampal volumes were reduced bilaterally in BPD patients with PTSD, relative to healthy controls, but that results were mixed for BPD patients without PTSD, relative to healthy controls.

Conclusions

Results from this meta-analysis suggest that hippocampal volumes are reduced in patients with BPD, relative to healthy controls, but particularly in cases in which patients are diagnosed with comorbid PTSD.

Hippocampal Volume in Psychiatric Diagnoses: Should Psychiatry Biomarker Research Account for Comorbidities?

Background

Many research papers claim that patients with specific psychiatric disorders (major depressive disorder, posttraumatic stress disorder, borderline personality disorder, alcohol use disorder, and others) have smaller hippocampi, but most of those reports compared patients to healthy controls. We hypothesized that if psychiatrically matched controls (psychiatric control, matched for demographics and psychiatric comorbidities) were used, much of the biomarker literature in psychiatric research would not replicate. We used hippocampus and amygdala volume only as examples, as these are very commonly replicated results in psychiatry biomarker research. We propose that psychiatry biomarker research could benefit from using psychiatric controls, as the use of healthy controls results in data that are not disorder-specific.

Method

Hippocampus/amygdala volumes were compared between major depressive disorder, sex-/age-/race-matched healthy control, and psychiatric control (N = 126/group). Similar comparisons were performed for posttraumatic stress disorder (N = 67), borderline personality disorder (N = 111), and alcohol use disorder (N = 136).

Results

Major depressive disorder patients had smaller left (p = 8.79 × 10⁻³) and right (p = 3.13 × 10⁻³) hippocampal volumes than healthy control. Posttraumatic stress disorder had smaller left (p = 0.018) and right (p = 8.64 × 10⁻⁴) hippocampi than healthy control. Borderline personality disorder had smaller right hippocampus (p = 7.90 × 10⁻³) and amygdala (p = 1.49 × 10⁻³) than healthy control. Alcohol use disorder had smaller right hippocampus (p = 0.034) and amygdala (p = .024) than healthy control. No differences were found between any of the four diagnostic groups and psychiatric control.

Conclusion

When psychiatric controls were used, there was no difference in hippocampal or amygdalar volume between any of the diagnoses studied and controls. This strategy (keeping all possible relevant variables matched between experimental groups) has been used to advance science for hundreds of years, and we propose should also be used in biomarker psychiatry research.

A systematic review of structural MRI investigations within borderline personality disorder: Identification of key psychological variables of interest going forward

Existing models of Borderline Personality Disorder (BPD) suggest that a combination of genetic vulnerability, childhood trauma, and disrupted attachment can lead to the marked emotional lability, impulsivity and interpersonal difficulties observed clinically. Brain structural differences in frontal, limbic and hippocampal regions have been reported in BPD. Less clear is how specific psychological factors relate to these structural differences, and how consistently this is found across studies. This was the focus of the present review. Eighteen studies published between 2004 and 2018 met inclusion criteria encompassing 990 participants. Study quality was assessed using the Nottingham-Ottawa Scale. We also introduce a newly devised scale to assess MRI reporting quality. The most frequently investigated psychological variable were impulsivity (9 studies), depression (8), trauma (6), aggression (6), severity of symptoms (3), global functioning, abuse and dissociation (2). Study quality varied, however, a trend was observed where newer studies were higher in reporting quality. Impulsivity demonstrated greater association with frontal structures, trauma related to the hypothalamus and limbic systems, and aggression with hippocampal and frontal structures. The present review recommends greater exploration of neurocognitive and psychosis-related features such as delusions, paranoia and voice-hearing in future studies, and to investigate cortical changes in longitudinal designs.

Affective interference in borderline personality disorder: The lethality of suicidal behavior predicts functional brain profiles

BACKGROUND

Negative affective interference with executive cognition is associated with emotion dysregulation and behavioral dyscontrol in BPD, including a diathesis to suicidal and self-injurious behavior. While clinically well described, the neural basis of affective interference with central executive network function, and resulting suicidal behavior is poorly understood.

METHOD

In an fMRI study, 23 BPD suicide attempters completed an affectively modified Continuous Performance Task(X-CPT), in which targets and distractors were rendered on Negative, Positive and Neutral Ekman faces, with a Distorted image as a behavioral baseline. Responses to targets were contextualized by the affective context of the face. Lethality Rating Scale scores (LRS) were modeled as the primary regressor of interest on activation peaks, with HamD scores covaried.

RESULTS

In the Negative vs. Neutral contrast, LRS scores were inversely related to activation in the ACC, parietal precuneus, BG and OFC, with no positive relationships. Results were similar in the Negative vs Positive contrast. In the Neutral vs. Positive contrast, activations were much less extensive, with mixed positive and negative relationships. Contextualizing responses based on the effects of valence decreased participant's ability to distinguish between targets and distracters; however, no differences were observed between valence contexts. fMRI-estimated effects were not confounded by differences in behavioral sensitivity across contexts.

LIMITATIONS

In this female-only sample, possible gender differences were not addressed.

CONCLUSIONS

With negative affective interference, increased lethality of suicidal behavior in BPD predicted diminished neural activation in areas critical to executive cognitive function. Therapies diminishing affective interference may reduce risk of suicidal behavior.

Some neuroanatomical insights to impulsive aggression in schizophrenia

Patients with schizophrenia are at increased risk of engaging in violence towards others, compared to both the general population and most other patient groups. We have here explored the role of cortico-limbic impairments in schizophrenia, and have considered these brain regions specifically within the framework of a popular neuroanatomical model of impulsive aggression. In line with this model, evidence in patients with aggressive schizophrenia implicated structural deficits associated with impaired decision-making, emotional control and evaluation, and social information processing, especially in the orbitofrontal and ventrolateral prefrontal cortex. Given the pivotal role of the orbitofrontal and ventrolateral cortex in emotion control and evaluation, structural deficits may result in inappropriate use of socially relevant information and improper recognition of impulses that are in need for regulation. Furthermore, we have extended the original model and incorporated the striatum, important for the generation of aggressive impulses, as well as the hippocampus, a region critical for decision-making, into the model. Lastly, we discuss the question whether structural impairments are specific to aggressive schizophrenia. Our results suggest, that similar findings can be observed in other aggressive patient populations, making the observed impairments non-specific to aggressive schizophrenia. This points towards a shared condition, across pathologies, a potential common denominator being impulsive aggression.

Longitudinal structural brain development and externalizing behavior in adolescence

BACKGROUND

Cross-sectional studies report relations between externalizing behavior and structural abnormalities in cortical thickness of prefrontal regions and volume reductions in subcortical regions. To understand how these associations emerge and develop, longitudinal designs are pivotal.

METHOD

In the current longitudinal study, a community sample of children, adolescents and young adults (N = 271) underwent magnetic resonance imaging (MRI) in three biennial waves (680 scans). At each wave, aspects of externalizing behavior were assessed with parent-reported aggression and rule-breaking scores (Child Behavior Checklist), and self-reported aggression scores (Buss-Perry Aggression Questionnaire). Regions of interest (ROIs) were selected based on prior research: dorsolateral prefrontal (dlPFC), orbitofrontal (OFC), anterior cingulate cortex (ACC), insula, and parahippocampal cortex, as well as subcortical regions. Linear mixed models were used to assess the longitudinal relation between externalizing behavior and structural brain development. Structural covariance analyses were employed to identify whether longitudinal relations between ROIs (maturational coupling) were associated with externalizing behavior.

RESULTS

Linear mixed model analyses showed a negative relation between parent-reported aggression and right hippocampal volume. Moreover, this longitudinal relation was driven by change in hippocampal volume and not initial volume of hippocampus at time point 1. Exploratory analyses showed that stronger maturational coupling between prefrontal regions, the limbic system, and striatum was associated with both low and high externalizing behavior.

CONCLUSIONS

Together, these findings reinforce the hypothesis that altered structural brain development coincides with development of more externalizing behavior. These findings may guide future research on normative and deviant development of externalizing behavior.

Alterations in brain microstructure in rats that develop abnormal aggression following peripubertal stress

Exposure to early adversity is implicated in the development of aggressive behaviour later in life in some but not all individuals. The reasons for the variability in response to such experiences are not clear but may relate to pre-existing individual differences that influence their downstream effects. Applying structural magnetic resonance imaging (MRI) to a rat model of abnormal aggression induced by peripubertal stress, we examined whether individual differences in the development of an aggressive phenotype following stress exposure were underpinned by variation in the structure of aggression-associated, corticolimbic brain regions. We also assessed whether responsiveness of the hypothalamic-pituitary-adrenal axis to stress was associated with neurobehavioural outcome following adversity. A subset of the rats exposed to peripubertal stress developed an aggressive phenotype, while the remaining rats were affected in other behavioural domains, such as increased anxiety-like behaviours and reduced sociability. Peripubertal stress led to changes in tissue microstructure within prefrontal cortex, amygdala and hippocampal formation only in those individuals displaying an aggressive phenotype. Attenuated glucocorticoid response to stress during juvenility predicted the subsequent development of an aggressive phenotype in peripubertal stress-exposed rats. Our study establishes a link between peripubertal stress exposure in rats and structural deviations in brain regions linked to abnormal aggression and points towards low glucocorticoid responsiveness to stress as a potential underlying mechanism. We additionally highlight the importance of considering individual differences in behavioural response to stress when determining neurobiological correlates.

Amygdala structure and aggressiveness in borderline personality disorder

Aggressiveness is considered an important clinical feature of borderline personality disorder (BPD) and has been associated with alterations of the amygdala. However, studies that analyzed the exact location of amygdala alterations associated with aggressiveness in BPD or that systematically compared female and male BPD patients are missing. In the current study, we therefore investigated a sex-mixed sample of BPD patients and healthy volunteers and applied an automated segmentation method that allows the study of both, alterations of amygdala volume and localized amygdala shape. Volumetric results revealed no difference in amygdala volume between BPD patients and healthy volunteers, but a trend for a positive association between volume of the right amygdala and aggressiveness in male BPD patients. Analyses of amygdala shape showed a trend for a group by sex interaction effect in the left laterobasal amygdala, without a difference in subgroup analyses. Finally, regions of the left superficial and laterobasal amygdala of male BPD patients were positively associated with aggressiveness. In sum, our results emphasize the need to consider sex-specific effects and demonstrate a link between male BPD patients' aggressiveness and amygdala regions that are particularly related to social information processing and associative emotional learning.

Epilepsy, Antiepileptic Drugs, and Aggression: An Evidence-Based Review

Antiepileptic drugs (AEDs) have many benefits but also many side effects, including aggression, agitation, and irritability, in some patients with epilepsy. This article offers a comprehensive summary of current understanding of aggressive behaviors in patients with epilepsy, including an evidence-based review of aggression during AED treatment. Aggression is seen in a minority of people with epilepsy. It is rarely seizure related but is interictal, sometimes occurring as part of complex psychiatric and behavioral comorbidities, and it is sometimes associated with AED treatment. We review the common neurotransmitter systems and brain regions implicated in both epilepsy and aggression, including the GABA, glutamate, serotonin, dopamine, and noradrenaline systems and the hippocampus, amygdala, prefrontal cortex, anterior cingulate cortex, and temporal lobes. Few controlled clinical studies have used behavioral measures to specifically examine aggression with AEDs, and most evidence comes from adverse event reporting from clinical and observational studies. A systematic approach was used to identify relevant publications, and we present a comprehensive, evidence-based summary of available data surrounding aggression-related behaviors with each of the currently available AEDs in both adults and in children/adolescents with epilepsy. A psychiatric history and history of a propensity toward aggression/anger should routinely be sought from patients, family members, and carers; its presence does not preclude the use of any specific AEDs, but those most likely to be implicated in these behaviors should be used with caution in such cases.

A Neurobiological Model of Borderline Personality Disorder: Systematic and Integrative Review

Borderline personality disorder (BPD) is a severe mental disorder with a multifactorial etiology. The development and maintenance of BPD is sustained by diverse neurobiological factors that contribute to the disorder's complex clinical phenotype. These factors may be identified using a range of techniques to probe alterations in brain systems that underlie BPD. We systematically searched the scientific literature for empirical studies on the neurobiology of BPD, identifying 146 articles in three broad research areas: neuroendocrinology and biological specimens; structural neuroimaging; and functional neuroimaging. We consolidate the results of these studies and provide an integrative model that attempts to incorporate the heterogeneous findings. The model specifies interactions among endogenous stress hormones, neurometabolism, and brain structures and circuits involved in emotion and cognition. The role of the amygdala in BPD is expanded to consider its functions in coordinating the brain's dynamic evaluation of the relevance of emotional stimuli in the context of an individual's goals and motivations. Future directions for neurobiological research on BPD are discussed, including implications for the Research Domain Criteria framework, accelerating genetics research by incorporating endophenotypes and gene × environment interactions, and exploring novel applications of neuroscience findings to treatment research.

Brain structural anomalies in borderline and avoidant personality disorder patients and their associations with disorder-specific symptoms

BACKGROUND

Borderline personality disorder (BPD) and avoidant personality disorder (AvPD) are characterized by hyper-reactivity to negatively-perceived interpersonal cues, yet they differ in degree of affective instability. Recent work has begun to elucidate the neural (structural and functional) and cognitive-behavioral underpinnings of BPD, although some initial studies of brain structure have reached divergent conclusions. AvPD, however, has been almost unexamined in the cognitive neuroscience literature.

METHODS

In the present study we investigated group differences among 29 BPD patients, 27 AvPD patients, and 29 healthy controls (HC) in structural brain volumes using voxel-based morphometry (VBM) in five anatomically-defined regions of interest: amygdala, hippocampus, medial prefrontal cortex (MPFC), dorsolateral prefrontal cortex (DLPFC), and anterior cingulate cortex (ACC). We also examined the relationship between individual differences in brain structure and self-reported anxiety and affective instability in each group.

RESULTS

We observed reductions in MPFC and ACC volume in BPD relative to HC, with no significant difference among patient groups. No group differences in amygdala volume were found. However, BPD and AvPD patients each showed a positive relationship between right amygdala volume and state-related anxiety. By contrast, in HC there was an inverse relationship between MPFC volume and state and trait-related anxiety as well as between bilateral DLPFC volume and affective instability.

LIMITATIONS

Current sample sizes did not permit examination of gender effects upon structure-symptom correlations.

CONCLUSIONS

These results shed light on potentially protective, or compensatory, aspects of brain structure in these populations-namely, relatively reduced amygdala volume or relatively enhanced MPFC and DLPFC volume.

Age-related parieto-occipital and other gray matter changes in borderline personality disorder: A meta-analysis of cortical and subcortical structures

Previous research suggests that core borderline personality disorder (BPD) symptoms vary in severity with advancing age. While structural neuroimaging studies show smaller limbic and prefrontal gray matter volumes (GMV) in primarily adult and adolescent BPD patients, respectively, findings are inconsistent. Using the effect-size signed differential mapping (ES-SDM) meta-analytic method, we investigated the relationship between advancing age and GMV abnormalities in BPD patients. A total of nine voxel-based morphometry (VBM) studies comparing regional GMV of 256 BPD patients and 272 healthy control subjects were included. Meta-analysis identified lower GMV in the right superior/middle temporal gyri and higher GMV in the right supplementary motor area of BPD patients. Meta-regression showed that increasing age was significantly associated with increased GMV in the left superior parieto-occipital gyri, with younger-aged patients starting at lower GMV compared to controls. In contrast, increasing age was associated with decreased GMV in the right amygdala. These findings suggest that while GMV deficits in limbic structures may become pronounced with advancing age in the course of BPD, parieto-occipital rather than frontal GMV deficits could be especially prominent in younger-aged BPD patients.

Brain morphology of childhood aggressive behavior: A multi-informant study in school-age children

OBJECTIVE

Few studies have focused on the neuroanatomy of aggressive behavior in children younger than 10 years. Here, we explored the neuroanatomical correlates of aggression in a population-based sample of 6- to 9-year-old children using a multiple-informant approach.

METHODS

Magnetic resonance (MR) scans were acquired from 566 children from the Generation R study who participated in the Berkeley Puppet Interview and whose parents had completed the Child Behavior Checklist. Linear regression analyses were used to examine associations between aggression and amygdala and hippocampal volume. We performed surface-based analyses to study the association between aggression and cortical thickness, surface area, and gyrification.

RESULTS

Aggressive behavior was associated with smaller amygdala (p < .05) but not hippocampal volume. Aggression was associated with a thinner cortex in the left precentral cortex (p < .01) and in a cluster including the right inferior parietal, supramarginal, and postcentral cortex (p < .001). Gender moderated the association between aggression and cortical thickness in the right medial posterior cortex (p = .001) and the right prefrontal cortex (p < .001). Aggression was associated with decreased gyrification in a large cluster including the right precentral, postcentral, frontal, and parietal cortex (p = .01). Moreover, aggression was associated with decreased gyrification in the right occipital and parietal cortex (p = .02).

CONCLUSION

We found novel evidence that childhood aggressive behavior is related to decreased amygdala volume, decreased sensorimotor cortical thickness, and decreased global right hemisphere gyrification. Aggression is related to cortical thickness in regions associated with the default mode network, with negative associations in boys and positive associations in girls.

Frontolimbic Morphometric Abnormalities in Intermittent Explosive Disorder and Aggression

BACKGROUND

Converging evidence from neuroimaging studies suggests that impulsive aggression, the core behavior in the DSM-5 diagnosis intermittent explosive disorder (IED), is regulated by frontolimbic brain structures, particularly orbitofrontal cortex, ventral medial prefrontal cortex, anterior cingulate cortex, amygdala, insula, and uncus. Despite this evidence, no brain volumetric studies of IED have been reported as yet. This study was conducted to test the hypothesis that gray matter volume in frontolimbic brain structures of subjects with IED is lower than in healthy subjects and subjects with other psychiatric conditions.

METHODS

High-resolution magnetic resonance imaging scans using a three-dimensional magnetization-prepared rapid acquisition gradient-echo sequence were performed in 168 subjects (n = 53 healthy control subjects, n = 58 psychiatric controls, n = 57 subjects with IED). Imaging data were analyzed by voxel-based morphometry methods employing Statistical Parametric Mapping (SPM8) software.

RESULTS

Gray matter volume was found to be significantly lower in subjects with IED compared with healthy control subjects and psychiatric controls in orbitofrontal cortex, ventral medial prefrontal cortex, anterior cingulate cortex, amygdala, insula, and uncus. These differences were not due to various confounding factors or to comorbidity with other disorders previously reported to have reduced gray matter volume. Gray matter volume in these areas was significantly and inversely correlated with measures of aggression.

CONCLUSIONS

Reductions in the gray matter volume of frontolimbic structures may be a neuronal characteristic of impulsively aggressive individuals with DSM-5 IED. These data suggest an anatomic correlate accounting for functional deficits in social-emotional information processing in these individuals.

Morphometric analysis of amygdla and hippocampus shape in impulsively aggressive and healthy control subjects

BACKGROUND

Impulsive aggressive behavior is thought to be facilitated by activation of the limbic brain, particularly the amygdala and hippocampus., Functional imaging studies suggest abnormalities in limbic brain activity during emotional information processing in impulsively aggressive subjects with Intermittent Explosive Disorder (IED). It is not known if IED is associated with altered amygdala and hippocampus volume and shape.

METHODS

We examined the volume and shape of the amygdala-hippocampal complex, using morphometric analysis of high resolution structural 3T MR scans in healthy control (HC: n = 73) subjects without history of Axis I or II psychiatric conditions and in subjects with IED (n = 67).

RESULTS

While no volume differences were observed between HC and IED subjects, a significant level of morphometric deformation, suggestive of cell loss, in both amygdala and hippocampal structures was observed bilaterally in IED subjects. Analysis of a canonical variable that used the first 10 eigenvectors from both sides of the brain revealed that these morphometric deformations in the IED subjects were not due the presence of confounding variables or to comorbidities among IED subjects.

CONCLUSIONS

These data reveal that IED is associated with a significant loss of neurons in both the amygdala and hippocampus. These changes may play a role in the functional abnormalities observed in previous fMRI studies and in the pathophysiology of impulsive aggressive behavior.

Long-term consequences of chronic fluoxetine exposure on the expression of myelination-related genes in the rat hippocampus

The selective serotonin reuptake inhibitor (SSRI) fluoxetine is widely prescribed for the treatment of symptoms related to a variety of psychiatric disorders. After chronic SSRI treatment, some symptoms remediate on the long term, but the underlying mechanisms are not yet well understood. Here we studied the long-term consequences (40 days after treatment) of chronic fluoxetine exposure on genome-wide gene expression. During the treatment period, we measured body weight; and 1 week after treatment, cessation behavior in an SSRI-sensitive anxiety test was assessed. Gene expression was assessed in hippocampal tissue of adult rats using transcriptome analysis and several differentially expressed genes were validated in independent samples. Gene ontology analysis showed that upregulated genes induced by chronic fluoxetine exposure were significantly enriched for genes involved in myelination. We also investigated the expression of myelination-related genes in adult rats exposed to fluoxetine at early life and found two myelination-related genes (Transferrin (Tf) and Ciliary neurotrophic factor (Cntf)) that were downregulated by chronic fluoxetine exposure. Cntf, a neurotrophic factor involved in myelination, showed regulation in opposite direction in the adult versus neonatally fluoxetine-exposed groups. Expression of myelination-related genes correlated negatively with anxiety-like behavior in both adult and neonatally fluoxetine-exposed rats. In conclusion, our data reveal that chronic fluoxetine exposure causes on the long-term changes in expression of genes involved in myelination, a process that shapes brain connectivity and contributes to symptoms of psychiatric disorders.

Self-reported impulsivity is negatively correlated with amygdalar volumes in cocaine dependence

Although impulsivity has been associated with cocaine dependence and other addictive behaviors, the biological factors underlying impulsivity have yet to be precisely determined. This study aimed to examine relationships between impulsivity and volumes of the amygdala and hippocampus in cocaine-dependent and healthy comparison individuals. The Barratt Impulsiveness Scale (BIS-11) was used to assess impulsivity. FreeSurfer was used to assess amygdalar and hippocampal volumes from high-resolution structural magnetic resonance images. Relative to healthy comparison subjects, cocaine-dependent individuals scored higher on all three subscales of BIS-11 but did not differ from healthy comparison subjects in amygdalar or hippocampal volumes. Cocaine-dependent individuals showed significant negative correlations between amygdalar volumes and scores on the BIS-11 Attentional subscale, and this relationship differed significantly from the non-significant relationship in healthy comparison subjects. As individual differences in amygdalar structure may contribute to the high impulsivity observed in cocaine-dependent individuals, the findings suggest that future studies should assess the extent to which therapies that target impulsivity in cocaine dependence may operate through the amygdala or alter its structure or function.

Affective context interferes with brain responses during cognitive processing in borderline personality disorder: fMRI evidence

Emotion dysregulation in borderline personality disorder (BPD) is associated with loss of cognitive control in the face of intense negative emotion. Negative emotional context may interfere with cognitive processing through the dysmodulation of brain regions involved in regulation of emotion, impulse control, executive function and memory. Structural and metabolic brain abnormalities have been reported in these regions in BPD. Using novel fMRI protocols, we investigated the neural basis of negative affective interference with cognitive processing targeting these regions. Attention-driven Go No-Go and X-CPT (continuous performance test) protocols, using positive, negative and neutral Ekman faces, targeted the orbital frontal cortex (OFC) and the anterior cingulate cortex (ACC), respectively. A stimulus-driven Episodic Memory task, using images from the International Affective Pictures System, targeted the hippocampus (HIP). Participants comprised 23 women with BPD, who were compared with 15 healthy controls. When Negative>Positive faces were compared in the Go No-Go task, BPD subjects had hyper-activation relative to controls in areas reflecting task-relevant processing: the superior parietal/precuneus and the basal ganglia. Decreased activation was also noted in the OFC, and increased activation in the amygdala (AMY). In the X-CPT, BPD subjects again showed hyper-activation in task-relevant areas: the superior parietal/precuneus and the ACC. In the stimulus-driven Episodic Memory task, BPD subjects had decreased activation relative to controls in the HIP, ACC, superior parietal/precuneus, and dorsal prefrontal cortex (dPFC) (for encoding), and the ACC, dPFC, and HIP for retrieval of Negative>Positive pictures, reflecting impairment of task-relevant functions. Negative affective interference with cognitive processing in BPD differs from that in healthy controls and is associated with functional abnormalities in brain networks reported to have structural or metabolic abnormalities. Task demands exert a differential effect on the cognitive response to negative emotion in BPD compared with control subjects.

Beating the brain about abuse: Empirical and meta-analytic studies of the association between maltreatment and hippocampal volume across childhood and adolescence

We present new empirical data and meta-analytic evidence for the association of childhood maltreatment with reduced hippocampal volume. In Study 1, we examined the effects of maltreatment experiences reported during the Adult Attachment Interview on hippocampal volume in female twin pairs. We found that reduced hippocampal volume was related to childhood maltreatment. In addition, individuals who reported having experienced maltreatment at older ages had larger reductions in hippocampal volume compared to individuals who reported maltreatment in early childhood. In Study 2, we present the results of a meta-analysis of 49 studies (including 2,720 participants) examining hippocampal volume in relation to experiences of child maltreatment, and test the moderating role of the timing of the maltreatment, the severity of maltreatment, and the time after exposure to maltreatment. The results of the meta-analysis confirmed that experiences of childhood maltreatment are associated with a reduction in hippocampal volume and that the effects of maltreatment are more pronounced when the maltreatment occurs in middle childhood compared to early childhood or adolescence.

Hippocampal neuroligin-2 links early-life stress with impaired social recognition and increased aggression in adult mice

Early-life stress is a key risk factor for the development of neuropsychiatric disorders later in life. Neuronal cell adhesion molecules have been strongly implicated in the pathophysiology of psychiatric disorders and in modulating social behaviors associated with these diseases. Neuroligin-2 is a synaptic cell adhesion molecule, located at the postsynaptic membrane of inhibitory GABAergic synapses, and is involved in synaptic stabilization and maturation. Alterations in neuroligin-2 expression have previously been associated with changes in social behavior linked to psychiatric disorders, including schizophrenia and autism. In this study, we show that early-life stress, induced by limited nesting and bedding material, leads to impaired social recognition and increased aggression in adult mice, accompanied by increased expression levels of hippocampal neuroligin-2. Viral overexpression of hippocampal neuroligin-2 in adulthood mimics early-life stress-induced alterations in social behavior and social cognition. Moreover, viral knockdown of neuroligin-2 in the adult hippocampus attenuates the early-life stress-induced behavioral changes. Our results highlight the importance of neuroligin-2 in mediating early-life stress effects on social behavior and social cognition and its promising role as a novel therapeutic target for neuropsychiatric disorders.

Role of the vasopressin 1b receptor in rodent aggressive behavior and synaptic plasticity in hippocampal area CA2

The vasopressin 1b receptor (Avpr1b) is critical for social memory and social aggression in rodents, yet little is known about its specific roles in these behaviors. Some clues to Avpr1b function can be gained from its profile of expression in the brain, which is largely limited to the pyramidal neurons of the CA2 region of the hippocampus, and from experiments showing that inactivation of the gene or antagonism of the receptor leads to a reduction in social aggression. Here we show that partial replacement of the Avpr1b through lentiviral delivery into the dorsal CA2 region restored the probability of socially motivated attack behavior in total Avpr1b knockout mice, without altering anxiety-like behaviors. To further explore the role of the Avpr1b in this hippocampal region, we examined the effects of Avpr1b agonists on pyramidal neurons in mouse and rat hippocampal slices. We found that selective Avpr1b agonists induced significant potentiation of excitatory synaptic responses in CA2, but not in CA1 or in slices from Avpr1b knockout mice. In a way that is mechanistically very similar to synaptic potentiation induced by oxytocin, Avpr1b agonist-induced potentiation of CA2 synapses relies on NMDA (N-methyl-D-aspartic acid) receptor activation, calcium and calcium/calmodulin-dependent protein kinase II activity, but not on cAMP-dependent protein kinase activity or presynaptic mechanisms. Our data indicate that the hippocampal CA2 is important for attacking in response to a male intruder and that the Avpr1b, likely through its role in regulating CA2 synaptic plasticity, is a necessary mediator.

Volume of hippocampal substructures in borderline personality disorder

Borderline personality disorder (BPD) may be associated with smaller hippocampi in comparison to hippocampal size in controls. However, specific pathology in hippocampal substructures (i.e., head, body and tail) has not been sufficiently investigated. To address hippocampal structure in greater detail, we studied 39 psychiatric inpatients and outpatients with a DSM-IV diagnosis of BPD and 39 healthy controls. The hippocampus and its substructures were segmented manually on magnetic resonance imaging scans. The volumes of hippocampal substructures (and total hippocampal volume) did not differ between BPD patients and controls. Exploratory analysis suggests that patients with a lifetime history of posttraumatic stress disorder (PTSD) may have a significantly smaller hippocampus - affecting both the hippocampal head and body - in comparison to BPD patients without comorbid PTSD (difference in total hippocampal volume: -10.5%, 95%CI -2.6 to -18.5, significant). Also, patients fulfilling seven or more DSM-IV BPD criteria showed a hippocampal volume reduction, limited to the hippocampal head (difference in volume of the hippocampal head: -16.5%, 95%CI -6.1 to -26.8, significant). Disease heterogeneity in respect to, for example, symptom severity and psychiatric comorbidities may limit direct comparability between studies; the results presented here may reflect hippocampal volumes in patients who are "less" affected or they may simply be a chance finding. However, there is also the possibility that global effects of BPD on the hippocampus may have previously been overestimated.

White matter integrity and its association with affective and interpersonal symptoms in borderline personality disorder

BACKGROUND

Borderline personality disorder (BPD) is a severe psychiatric disorder involving a range of symptoms including marked affective instability and disturbances in interpersonal interactions. Neuroimaging studies are beginning to provide evidence of altered processing in fronto-limbic network deficits in the disorder, however, few studies directly examine structural connections within this circuitry together with their relation to proposed causative processes and clinical features.

METHODS

In the current study, we investigated whether individuals with BPD (n = 20) have deficits in white matter integrity compared to a matched group of healthy controls (n = 18) using diffusion tensor MRI (DTI). We hypothesized that the BPD group would have decreased fractional anisotropy (FA), a measure of white matter integrity, compared to the controls in white matter tracts connecting frontal and limbic regions, primarily the cingulum, fornix and uncinate fasciculus. We also investigated the extent to which any such deficits related to childhood adversity, as measured by the childhood trauma questionnaire, and symptom severity as measured by the Zanarini rating scale for BPD.

RESULTS

We report decreased white matter integrity in BPD versus controls in the cingulum and fornix. There were no significant relationships between FA and measures of childhood trauma. There were, however, significant associations between FA in the cingulum and clinical symptoms of anger, and in the fornix with affective instability, and measures of avoidance of abandonment from the Zanarini rating scale.

CONCLUSIONS

We report deficits within fronto-limbic connections in individuals with BPD. Abnormalities within the fornix and cingulum were related to severity of symptoms and highlight the importance of these tracts in the pathogenesis of the disorder.

Mild expression differences of MECP2 influencing aggressive social behavior

The X-chromosomal MECP2/Mecp2 gene encodes methyl-CpG-binding protein 2, a transcriptional activator and repressor regulating many other genes. We discovered in male FVB/N mice that mild (∼50%) transgenic overexpression of Mecp2 enhances aggression. Surprisingly, when the same transgene was expressed in C57BL/6N mice, transgenics showed reduced aggression and social interaction. This suggests that Mecp2 modulates aggressive social behavior. To test this hypothesis in humans, we performed a phenotype-based genetic association study (PGAS) in >1000 schizophrenic individuals. We found MECP2 SNPs rs2239464 (G/A) and rs2734647 (C/T; 3′UTR) associated with aggression, with the G and C carriers, respectively, being more aggressive. This finding was replicated in an independent schizophrenia cohort. Allele-specific MECP2mRNA expression differs in peripheral blood mononuclear cells by ∼50% (rs2734647: C > T). Notably, the brain-expressed, species-conserved miR-511 binds to MECP2 3′UTR only in T carriers, thereby suppressing gene expression. To conclude, subtle MECP2/Mecp2 expression alterations impact aggression. While the mouse data provides evidence of an interaction between genetic background and mild Mecp2 overexpression, the human data convey means by which genetic variation affects MECP2 expression and behavior.

Hippocampal and amygdalar volumetric differences in pathological gambling: a preliminary study of the associations with the behavioral inhibition system

The behavioral inhibition system (BIS) and behavioral activation system (BAS) are hypothesized to underlie motivated behavior, relate to hippocampal and amygdalar function, and link to pathological gambling (PG). Prior studies have not investigated hippocampal and amygdalar volumes in PG and their relationships to BIS/BAS measures. Structural MRI scans and BIS/BAS and other clinical measures were obtained from 32 PG individuals and 47 healthy comparison (HC) individuals. Volumetric measures of the hippocampus and amygdala were assessed using FreeSurfer and related to BIS/BAS measures. PG relative to HC individuals demonstrated diminished volume in the left hippocampus and right amygdala and higher BIS and BAS scores. BIS scores were positively correlated with left hippocampal and left amygdalar volumes in PG individuals. The findings of relatively diminished hippocampal and amygdalar volumes in PG individuals resonate with findings from substance-dependent groups. Relationships between amygdalar and hippocampal volumes and BIS measures in PG suggest that individual differences in these structures may contribute to avoidance behaviors in PG.

Mesiotemporal volume loss associated with disorder severity: a VBM study in borderline personality disorder

Results of MRI volumetry in Borderline Personality Disorder (BPD) are inconsistent. Some, but not all, studies reported decreased hippocampus, amygdala, and/or prefrontal volumes. In the current study, we used rater-independent voxel-based morphometry (VBM) in 33 female BPD patients and 33 healthy women. We measured gray matter (GM) volumes of the whole brain and of three volumes of interest (VOI), i.e., the hippocampus/parahippocampal gyrus, the amygdala and the anterior cingulate gyrus (ACC). Analyses were conducted using lifetime diagnoses of posttraumatic stress disorder (PTSD) and major depression (MD) as covariates. We used adversive childhood experiences and the numbers of BPD criteria (as an indicator of disorder severity) to investigate associations with GM volumes. We did not find volume differences between BPD patients and healthy subject, neither of the whole brain nor of the three VOIs, independent of presence or absence of comorbid PTSD and MD. We also did not find a relationship between childhood maltreatment and the patients’ brain volumes. However, within the patient group, the number of BPD criteria fulfilled was inversely correlated with left hippocampal/parahippocampal volume (x=-32, y=-23, z=-18, k=496, t=5.08, p=.007). Consequently, mesiotemporal GM volumes do not seem to differentiate patients from healthy subjects, but might be associated with symptom severity within the BPD group.

Developmental differences in diffusion tensor imaging parameters in borderline personality disorder

BACKGROUND

Borderline personality disorder (BPD) often presents during adolescence. Early detection and intervention decreases its subsequent severity. However, little is known about early predictors and biological underpinnings of BPD. The observed abnormal functional connectivity among brain regions in BPD led to studies of white matter, as the neural substrate of connectivity. However, diffusion tensor imaging (DTI) studies in adult BPD have been inconclusive, and, as yet, there are no published DTI studies in borderline adolescents.

METHODS

We conducted DTI tractography in 38 BPD patients (14-adolescents, 24-adults) and 32 healthy controls (13-adolescents, 19-adults).

RESULTS

We found bilateral tract-specific decreased fractional anisotropy (FA) in inferior longitudinal fasciculus (ILF) in BPD adolescents compared to adolescent controls. ILF FA was significantly higher in adolescent controls compared to BPD adolescents, BPD adults and adult controls (Wilks F(3,57) = 3.55, p < 0.02). Follow-up voxelwise TBSS analysis demonstrated lower FA in BPD adolescents compared to adolescent controls also in uncinate and occipitofrontal fasciculi.

DISCUSSION

FA generally develops along an inverted U-shape curve, increasing through adolescence, and slowly decreasing in adulthood. Our findings suggest that, in adolescent BPD, this normal developmental "peak" in FA, which is seen in healthy controls, is not achieved. This suggests a possible neural substrate for the previously reported OFC-amygdala disconnect in adults with BPD. It raises the possibility that a white matter tract abnormality in BPD present in adolescence may not be appreciable in adulthood, but a functional abnormality in the coordination among brain regions persists. Our finding represents a possible biological marker to identify those at risk for developing BPD.

Magnetic resonance imaging in patients with borderline personality disorder: a study of volumetric abnormalities

Volumetric abnormalities of the hippocampus and frontal cortex are of major interest in the study of borderline personality disorder (BPD). To our knowledge, no study has examined volumetric abnormalities in the hippocampal subregions (head, body, and tail). Our aims were to investigate hippocampal volumetric abnormalities as well as abnormalities in the gray and white matter of the frontal cortex, basal ganglia, and anterior cingulate cortex in BPD in a sample of BPD patients compared to healthy controls. Using manual volumetry as well as optimized voxel based morphometry (VBM) we assessed the volumetric differences in a sample of females with BPD (n=20), compared to healthy female controls (n=21) (HC). The analyses revealed reductions in the left hippocampal head, body, and tail, and the right hippocampal tail. Hippocampal changes were confirmed also using VBM and additional volumetric reductions were found in the caudate and dorsolateral prefrontal cortex of the BPD group. Our study reaffirms the existence of hippocampal volumetric, prefrontal and caudate abnormalities in BPD and lends support to the stress-related explanation of these reductions, whilst also bringing new data to the topic in terms of the abnormalities found in the subregions.

Neurocognitive profiles of people with borderline personality disorder

PURPOSE OF REVIEW

This review summarizes recent neurocognitive research to better delineate the nosology, prognostication and cause underlying borderline personality disorder (BPD).

RECENT FINDINGS

BPD had marked clinical heterogeneity with high comorbidity. Executive dysfunction in this disorder was linked to suicidality and treatment adherence, and may serve as an endophenotype. BPD was also characterized by cognitive distortions such as risky decision-making, deficient feedback processing, dichotomous thinking, jumping to conclusion, monocausal attribution and paranoid cognitive style. Social cognition deficits recently described in BPD include altered social inference and emotional empathy, hypermentalization, poorer facial emotional recognition and facial expressions. In electrophysiological studies, BPD was found to have predominantly right hemispheric deficit in high-order cortical inhibition. Reduced left orbitofrontal activity by visual evoked potential and magnetoencephalography correlated with depressive symptoms and functional deterioration. Brain structures implicated in BPD include the hippocampus, dorsolateral prefrontal cortex and anterior cingulate cortex. Abnormal anatomy and functioning of frontolimbic circuitry appear to correlate with cognitive deficits.

SUMMARY

Frontolimbic structural and functional abnormalities underlie the broad array of cognitive abnormalities in BPD. Further research should espouse broader considerations of effects of comorbidity and clinical heterogeneity, and include community samples and, possibly, longitudinal designs.

Loudness dependence of auditory evoked potentials in patients with borderline personality disorder--impact of psychopathology

Alterations of the central serotonergic system are considered to be involved in the pathophysiology of borderline personality disorder (BPD). The loudness dependence of the N1/P2 component of auditory evoked potentials (LD) has been shown to indirectly reflect central serotonergic activity. The aim of this study was to investigate LD in patients with BPD compared to healthy controls, and to evaluate the association between LD and psychopathology such as anxiety, anger or impulsiveness. Female patients with BPD were included and compared to age- and sex-matched healthy subjects. Self-rating instruments, such as the State-Trait Anxiety Inventory (STAI), State-Trait Anger Expression Inventory (STAXI), and the Barratt Impulsiveness Scale (BIS) were used to assess clinical scores of anxiety, anger, and impulsiveness. Evoked potentials were recorded following the application of acoustic stimuli with increasing intensities; the LD was analysed using dipole source analysis. The mean LD was significantly higher in patients with BPD compared to controls. In the entire sample there were significant positive correlations of LD with state anxiety scores and STAXI subscores. The data contribute to the knowledge of neurophysiological alterations in patients with BPD, supporting the hypothesis of serotonergic dysregulation in the pathophysiology of the disorder. The significant clinical correlations suggest monoaminergic modulations of psychopathology on the symptom level.

Amygdalar volume in borderline personality disorder with and without comorbid post-traumatic stress disorder: a meta-analysis

INTRODUCTION

Four studies have found a smaller amygdalar volume in patients with borderline personality disorder (BPD) relative to controls, whereas four other studies have found similar amygdalar volume in BPD patients relative to controls. This study aims to compare amygdalar volumes of BPD patients with controls, and also to compare BPD patients with and without post-traumatic stress disorder (PTSD) with controls in order to determine whether PTSD can explain the heterogeneity of findings.

METHOD

Systematic review and meta-analysis of magnetic resonance imaging studies that measured amygdalar volumes in BPD patients and healthy controls.

FINDINGS

A significant reduction of amygdalar volumes in BPD patients was confirmed (p < .001). However, data from the studies that discriminated BPD patients with and without PTSD indicated that amygdalar volumes were significantly smaller in BPD patients without PTSD relative to controls (left: p = .02; right: p = .05), but not in BPD patients with PTSD relative to controls (left: p = .08; right: p = .20).

CONCLUSION

This meta-analysis suggests that amygdalar volumes are reduced in patients with BPD. This pattern is confirmed in BPD patients without PTSD, but not in BPD patients with PTSD, raising the possibility that reduced amygdalar volume in BPD patients cannot be explained by comorbid PTSD.

Structural brain abnormalities and suicidal behavior in borderline personality disorder

BACKGROUND

Structural brain abnormalities have been demonstrated in subjects with BPD in prefrontal and fronto-limbic regions involved in the regulation of emotion and impulsive behavior, executive cognitive function and episodic memory. Impairment in these cognitive functions is associated with increased vulnerability to suicidal behavior. We compared BPD suicide attempters and non-attempters, high and low lethality attempters to healthy controls to identify neural circuits associated with suicidal behavior in BPD.

METHODS

Structural MRI scans were obtained on 68 BPD subjects (16 male, 52 female), defined by IPDE and DIB/R criteria, and 52 healthy controls (HC: 28 male, 24 female). Groups were compared by diagnosis, attempt status, and attempt lethality. ROIs were defined for areas reported to have structural or metabolic abnormalities in BPD, and included: mid-inf. orbitofrontal cortex, mid-sup temporal cortex, anterior cingulate, insula, hippocampus, amygdala, fusiform, lingual and parahippocampal gyri. Data were analyzed using optimized voxel-based morphometry implemented with DARTEL in SPM5, co-varied for age and gender, corrected for cluster extent (p < .001).

RESULTS

Compared to HC, BPD attempters had significantly diminished gray matter concentrations in 8 of 9 ROIs, non-attempters in 5 of 9 ROIs. Within the BPD sample, attempters had diminished gray matter in Lt. insula compared to non-attempters. High lethality attempters had significant decreases in Rt. mid-sup. temporal gyrus, Rt. mid-inf. orbitofrontal gyrus, Rt. insular cortex, Lt. fusiform gyrus, Lt. lingual gyrus and Rt. parahippocampal gyrus compared to low lethality attempters.

CONCLUSIONS

Specific structural abnormalities discriminate BPD attempters from non-attempters and high from low lethality attempters.

Amygdala and hippocampal volume reductions as candidate endophenotypes for borderline personality disorder: a meta-analysis of magnetic resonance imaging studies

Borderline personality disorder (BPD) is a genetically influenced psychiatric illness with disruptions in neural systems supporting cognition and emotion regulation. Volumetric decreases of the hippocampus and amygdala may characterize BPD and serve as putative endophenotypes for the illness. The purpose of the present study was to evaluate whether the magnitude of these volume reductions and their associations with state-of-illness factors and psychiatric disorders which often co-occur with BPD warrant their consideration as potential endophenotypes. Volumetric magnetic resonance imaging results from 11 studies comprising 205 BPD patients and 222 healthy controls were quantitatively synthesized using meta-analytic techniques. Patients showed an average 11% and 13% decrease in the size of the hippocampus and amygdala, respectively. These volumetric differences were not attenuated in patients being treated with psychotropic medications. Comorbid depression, post-traumatic stress disorder, and substance use disorders were unrelated to volumetric decreases in either structure. These findings suggest modest volume reductions of the amygdala and hippocampus bilaterally in BPD which cannot be attributed to illness state or comorbid psychopathology. Decreased volumes of these key limbic structures may hold promise as candidate endophenotypes for BPD.

Impulse control and criminal responsibility: lessons from neuroscience

Almost all of the world's legal systems recognize the "M'Naghten" exception to criminal responsibility: the inability to appreciate the wrongfulness of action. This exception rests on the assumption that punishment is morally justified only if the defendant was able to choose whether to do wrong. Jurists and jurisdictions differ, however, on whether to extend M'Naghten's logic to cases where the defendant understood the wrongfulness of an act but was incapable of resisting an impulse to commit it. In this article I ask whether contemporary neuroscience can help lawmakers to decide whether to adopt or retain this defense, known variously as the "irresistible impulse" defense or the "control" or "volitional" test for insanity. More specifically, I ask firstly, whether it is empirically true that a person can understand the wrongfulness of an act yet be powerless to refrain from committing it; and second (assuming an affirmative answer to the first), whether the law of criminal responsibility can practically accommodate this phenomenon? After canvassing the relevant neuroscientific literature, I conclude that the answer to the first question is "yes." After examining the varied treatment of the defense in the United States and other nations, I also give an affirmative answer to the second question, but only in limited circumstances. In short, the defense of irresistible impulse should be recognized, but only when it can be shown that the defendant experienced a total incapacity to control his or her conduct in the circumstances.

Fronto-limbic dysfunction in borderline personality disorder: a 18F-FDG positron emission tomography study

INTRODUCTION

Several functional neuroimaging studies have demonstrated abnormalities in fronto-limbic pathways when comparing borderline personality disorder (BPD) patients with controls. The present study aimed to evaluate regional cerebral metabolism in euthymic BPD patients with similar measured impulsivity levels by means of 18F-FDG PET during resting state and to compare them against a control group.

METHODS

The present study evaluates regional cerebral metabolism in 8 euthymic BPD patients with 18F-FDG PET during resting state as compared to 8 controls with similar socio-geographic characteristics.

RESULTS

BPD patients presented a marked hypo-metabolism in frontal lobe and showed hyper-metabolism in motor cortex (paracentral lobules and post-central cortex), medial and anterior cingulus, occipital lobe, temporal pole, left superior parietal gyrus and right superior frontal gyrus. No significant differences appeared in basal ganglia or thalamus.

CONCLUSIONS

Results reveal a dysfunction in patients' frontolimbic network during rest and provide further evidence for the importance of these regions in relation to BPD symptomatology.

Dorsolateral prefrontal cortex and hippocampus sustain impulsivity and aggressiveness in borderline personality disorder

BACKGROUND

Borderline Personality Disorder (BPD) patients are characterized by increased levels of aggressivity and reduction of impulse control, which are behavioural dimensions mainly sustained by hippocampus and dorsolateral prefrontal cortex (DLPFC). In this study we aimed at investigating whether hippocampus and DLPFC anatomy may sustain impulsive and aggressive behaviours in BPD.

METHODS

Fifteen DSM-IV BPD patients (11 females, 4 males) and fifteen 1:1 matched healthy controls (11 females, 4 males) were studied with a 1.5T magnetic resonance imaging (MRI) and underwent a psychopathological assessment in order to measure the severity of aggressive and impulsive traits.

RESULTS

Right hippocampal volumes were significantly reduced in BPD patients compared to healthy subjects (p=0.027), particularly in those with a history of childhood abuse (p=0.01). Moreover, in patients but not in controls, right hippocampal volumes significantly inversely correlated with aggressiveness and DLPFC grey matter volumes significantly inversely associated with impulsiveness (p<0.05).

CONCLUSIONS

Our results provide evidence that hippocampus and DLPFC play a separate and unique role in sustaining the control of impulse and aggressive behaviours in BPD patients.

Neurobiological basis of parenting disturbance

OBJECTIVE

It has been proposed that early attachment relationships shape the structure and reactivity of social brain structures that underlie later social capacities. We provide a review of the literature surrounding the development of neurological regulatory systems during infancy and outline recent research suggesting these systems go on to underlie adaptive parental responses.

METHOD

We review evidence in the peer-reviewed psychiatric literature including (i) observational human literature on the neurobiological and social sequelae of early parenting experiences, (ii) experimental animal literature on the effects of early maternal care on neurological development, (iii) experimental animal literature on the neurobiological underpinnings of parenting behaviours, (iv) observational and fMRI evidence on the neurobiological correlates of parenting behaviours, (v) functional and volumetric imaging studies on adults affected by borderline personality disorder.

RESULTS

The development of infant regulatory systems is influenced by early parenting experiences. These frontolimbic regulatory systems are also heavily implicated in normal parental responses to infant cues. These frontolimbic disturbances are also observed in studies of borderline personality disorder; a disorder associated with poor emotional regulation, early trauma and disturbed parenting.

CONCLUSIONS

While the current literature is limited to animal models of abnormal care giving, existing disorders associated with deficits in regulatory capacity and abnormal frontolimbic functioning may yet provide a human model of the neurobiology of parenting disturbance.

Metabolite alterations in the hippocampus of high-functioning adult subjects with autism

The aim of the present study was to investigate metabolite alterations in the hippocampal formation as they relate to aggression in high-functioning adults with autism. We measured concentrations of N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine plus phosphocreatine (Cr+PCr) in the hippocampal formation by proton magnetic resonance spectroscopy in 12 non-medicated male subjects with autism and 12 age- and sex-matched controls. Aggression was scored in the autistic subjects using the Buss-Perry Aggression Questionnaire. The concentrations of Cho and Cr+PCr in the hippocampal formation in autistic subjects were significantly higher than the corresponding values in control subjects, and a significant positive correlation was observed between the concentrations of these metabolites in the hippocampal formation and scores on the Buss-Perry Aggression Questionnaire in autistic subjects. Results suggest that high-functioning adult subjects with autism have abnormal metabolite concentrations in the hippocampal formation, which may in part account for their aggression.

Superior temporal gyrus volume in teenagers with first-presentation borderline personality disorder

This magnetic resonance imaging study investigated the superior temporal gyrus (STG) subregion volumes in 20 teenagers with first-presentation borderline personality disorder (BPD) and 20 healthy controls. While the STG volume early in the course of BPD did not differ from that of healthy controls, the BPD participants with violent episodes had a smaller left caudal STG volume compared with those without such episodes during the previous 6 months. Our preliminary findings might reflect the neurobiological heterogeneity of the disorder.