Monoamine Oxidase-A Genetic Variants and Childhood Abuse Predict Impulsiveness in Borderline Personality Disorder

Differential methylation of OPRK1 in borderline personality disorder is associated with childhood trauma

According to a growing body of neurobiological evidence, the core symptoms of borderline personality disorder (BPD) may be linked to an opioidergic imbalance between the hedonic and stimulatory activity of mu opioid receptors (MOR) and the reward system inhibiting effects of kappa opioid receptors (KOR). Childhood trauma (CT), which is etiologically relevant to BPD, is also likely to lead to epigenetic and neurobiological adaptations by extensive activation of the stress and endogenous opioid systems. In this study, we investigated the methylation differences in the promoter of the KOR gene (OPRK1) in subjects with BPD (N = 47) and healthy controls (N = 48). Comparing the average methylation rates of regulatorily relevant subregions (specified regions CGI-1, CGI-2, EH1), we found no differences between BPD and HC. Analyzing individual CG nucleotides (N = 175), we found eight differentially methylated CG sites, all of which were less methylated in BPD, with five showing highly interrelated methylation rates. This differentially methylated region (DMR) was found on the falling slope (5') of the promoter methylation gap, whose effect is enhanced by the DMR hypomethylation in BPD. A dimensional assessment of the correlation between disease severity and DMR methylation rate revealed DMR hypomethylation to be negatively associated with BPD symptom severity (measured by BSL-23). Finally, analyzing the influence of CT on DMR methylation, we found DMR hypomethylation to correlate with physical and emotional neglect in childhood (quantified by CTQ). Thus, the newly identified DMR may be a biomarker of the risks caused by CT, which likely epigenetically contribute to the development of BPD.

Why Is Maternal Control Harmful? The Relation between Maternal Control, Insecure Attachment and Antisocial Personality Disorder Features in Chinese College Students: A Sequential Mediation Model

BACKGROUND

Previous work has indicated that a negative parenting style is associated with antisocial personality disorder features in Chinese college students, yet few studies have explored the unique role of negative mothering in children's antisocial personality disorder.

METHODS

The current study mainly examined the sequential mediation effect of parental antipathy and neglect (PAN) and mother negative loving (a form of insecure attachment) in the association between mother control and adulthood antisocial personality disorder features (ASPD features) in the framework of attachment theory and cognitive-behavioral theory. A community sample of 1547 Chinese college students filled in the Parental Bonding Instrument, the Childhood Experience of Care and Abuse Questionnaire, the Adult Attachment Questionnaire and the Personality Diagnostic Questionnaire-4+.

RESULTS

A sequential mediation model analysis showed that maternal control significantly predicted PAN, mother negative loving, as well as ASPD features.

CONCLUSIONS

Mother control and mother negative loving appear to advance on the development and exacerbation of ASPD features in college students.

Role of White Matter Microstructure in Impulsive Behavior

OBJECTIVE

Increased impulsivity is a hallmark trait of some neuropsychiatric illnesses, including addiction, traumatic brain injury, and externalizing disorders. The authors hypothesized that altered cerebral white matter microstructure may also underwrite normal individual variability in impulsive behaviors and tested this among healthy individuals.

METHODS

Impulsivity and diffusion tensor imaging (DTI) data were collected from 74 healthy adults (32 women; mean age=36.6 years [SD=13.6]). Impulsivity was evaluated using the Barratt Impulsiveness Scale-11, which provides a total score and scores for three subdomains: attentional, motor, and nonplanning impulsiveness. DTI was processed using the Enhancing Neuro Imaging Genetics Through Meta Analysis-DTI analysis pipeline to measure whole-brain and regional white matter fractional anisotropy (FA) values in 24 tracts.

RESULTS

Whole-brain total average FA was inversely correlated with motor impulsiveness (r=-0.32, p=0.007) and positively correlated with nonplanning impulsiveness (r=0.29, p=0.02); these correlations were significant after correction for multiple comparisons. Additional significant correlations were observed for motor impulsiveness and regional FA values for the corticospinal tract (r=-0.29, p=0.01) and for nonplanning impulsiveness and regional FA values for the superior fronto-occipital fasciculus (r=0.32, p=0.008).

CONCLUSIONS

These results provide initial evidence that the motor and nonplanning subdomains of impulsive behavior are linked to specific white matter microstructural connectivity, supporting the notion that impulsivity is in part a network-based construct involving white matter microstructural integrity among otherwise healthy populations.

Nature and nurture? A review of the literature on childhood maltreatment and genetic factors in the pathogenesis of borderline personality disorder

BACKGROUND

Borderline Personality Disorder (BPD) is a psychiatric disorder associated with significant morbidity and mortality. However, the neurobiological alterations underlying the condition remain poorly understood. As a result, existing treatments remain inadequate. One of the main risk factors for the development of BPD is a history of childhood maltreatment. However, it is considered neither causative nor specific to the condition. Current theory is therefore increasingly moving toward a 'Gene x Environment' (GxE) model of the condition. The purpose of the current work was to conduct a systematic literature review, which comprehensively identifies all published molecular level GxE studies that have explored the role of specific genetic loci, in influencing the risk of BPD following exposure to childhood abuse or neglect.

METHODS

Four electronic databases were used to systematically search for molecular level GxE studies of any design, which focused on the development of BPD following exposure to childhood abuse or neglect, without language or date restrictions. Articles were screened independently by two reviewers and results were synthesized narratively.

RESULTS

A total of 473 articles were screened of which sixteen were selected for inclusion in our review. Implicated genes were categorised according to their influence on; Neurotransmitter Systems, Neurodevelopment and Neuroendocrine Systems.

CONCLUSIONS

The identified studies have produced several relevant and statistically significant results. Of particular note, is the repeated finding that genes involved in HPA axis regulation, may be altered by exposure to childhood maltreatment, influencing subsequent susceptibility to BPD. This is both biologically plausible and of potential clinical significance.

The Effects of Childhood Maltreatment on Non-Suicidal Self-Injury in Male Adolescents: The Moderating Roles of the Monoamine Oxidase A (MAOA) Gene and the Catechol-O-Methyltransferase (COMT) Gene

(1) Background: Numerous studies suggest strong associations between childhood maltreatment and nonsuicidal self-injury (NSSI); this is also true for the roles of dopaminergic genes in the etiology of some psychopathologies related to NSSI. Investigating the interactions of environments and genes is important in order to better understand the etiology of NSSI. (2) Methods: Within a sample of 269 Chinese male adolescents (Mage = 14.72, SD = 0.92), childhood maltreatment and NSSI were evaluated, and saliva samples were collected for MAOA T941G and COMT Val158Met polymorphism analyses. (3) Results: The results revealed no primary effects attributable to MAOA T941G and COMT Val158Met polymorphism on NSSI. However, there was a significant three-way interaction between MAOA, COMT, and child abuse (β = −0.34, p < 0.01) in adolescent NSSI. Except for carriers of the T allele of MAOA and the Met allele of COMT, all studied male adolescents displayed higher NSSI scores when exposed to a higher level of child abuse. A similar three-way interaction was not observed in the case of child neglect. (4) Conclusions: The results indicate that the MAOA gene and COMT gene play moderating roles in the association between child abuse and NSSI of male adolescents and suggest the polygenic underpinnings of NSSI.

Are Owls and Larks Different When it Comes to Aggression? Genetics, Neurobiology, and Behavior

This review focuses on the contribution of circadian rhythms to aggression with a multifaceted approach incorporating genetics, neural networks, and behavior. We explore the hypothesis that chronic circadian misalignment is contributing to increased aggression. Genes involved in both circadian rhythms and aggression are discussed as a possible mechanism for increased aggression that might be elicited by circadian misalignment. We then discuss the neural networks underlying aggression and how dysregulation in the interaction of these networks evoked by circadian rhythm misalignment could contribute to aggression. The last section of this review will present recent human correlational data demonstrating the association between chronotype and/or circadian misalignment with aggression. With circadian rhythms and aggression being a burgeoning area of study, we hope that this review initiates more interest in this promising and topical area.

Correlates of Aggression in Personality Disorders: an Update

PURPOSE OF REVIEW

This review article aims at giving an update on studies investigating correlates of aggression in personality disorders during the last 5 years.

RECENT FINDINGS

Most data refer to borderline personality disorder (BPD) and antisocial personality disorder (ASPD). In BPD, emotion dysregulation, hypersensitivity to interpersonal rejection/threat, increased rumination, increased negative urgency, aggression-related knowledge structures, and invalidation were either corroborated or emerged as psychological correlates of aggression, while reduced ambiguity sensitivity, hyposensitivity to interpersonal threat, and reduced mindfulness were associated with aggression in ASPD. Neurobiologically, alterations of the monoaminooxidase-A-, the oxytocinergic-, and the prefrontal-limbic-system as well as increases of the thyroid hormone T3, γ-aminobutyric acid and several inflammatory markers were associated with increased aggression across various personality disorders. Our understanding of correlates of aggression in personality disorders has increased over the last 5 years. More efforts in improving the conceptualization of personality disorders and aggression are needed to develop innovative treatments for those affected.