ABCG1 gene variants in suicidal behavior and aggression-related traits

Sex difference in association between suicide attempts and lipid profile in first-episode and drug naive patients with major depressive disorder

BACKGROUND

The relationship between suicide attempts and lipid profiles in patients with major depressive disorder (MDD) remains uncertain. The purpose of this study was to investigate sex differences in the relationship between suicide attempts and plasma lipid profiles in a large sample of first-episode and drug naive (FEDN) MDD patients.

METHODS

We recruited 1718 FEDN MDD patients and gathered demographic, clinical, and blood lipid data. The Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale and the Positive and Negative Syndrome Scale were used to assess the symptoms of patients.

RESULTS

There was no significant difference in the prevalence of suicide attempts between male and female MDD patients. The suicide attempt group had higher levels of depression, anxiety, psychotic symptoms, total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C), but lower levels of high-density lipoprotein cholesterol (HDL-C) levels than the non-suicide attempt group. Binary logistic regression showed that TC levels were significantly correlated with suicidal attempts in both male and female patients. Correlation analysis revealed that the levels of TC, HDL-C and LDL-C were significantly associated with the number of suicide attempts in both male and female patients. Further multiple linear regression revealed that TC levels were significantly associated with the number of suicide attempts in male patients only.

CONCLUSIONS

Lipid biomarkers, particularly high TC levels, are associated with suicide attempts in both male and female MDD patients. However, there is gender difference in association between lipid biomarkers, especially TC levels, and the number of suicide attempts in MDD patients.

Type of childhood maltreatment and the risk of criminal recidivism in adult probationers: a cross-sectional study

BACKGROUND

Childhood maltreatment is strongly associated with delinquency and the repeated crime. Specific types of childhood maltreatment have been found to have differential effects on recidivism in juvenile offenders, but studies of adult probationers have not been performed. This study investigated the relationship between having a history of childhood maltreatment and mental-health problems and the independent contribution of specific types of maltreatment and mental-health problems to the criminal recidivism of adult probationers.

METHOD

This study included 183 adult probationers (107 males and 76 females) with a mean age of 40.1 (SD = 11.8) years. Type of childhood maltreatment was assessed using the Childhood Trauma Questionnaire, which consists of five subscales (emotional neglect and abuse, physical neglect and abuse, and sexual abuse). Additionally, we used the Mini International Neuropsychiatric Interview to assess participants for the presence of psychiatric disorders and assessed levels of emotional dysregulation and resilience. Hierarchical logistic regression analysis was performed to determine whether the types of childhood maltreatment were independently associated with repeated crime, after adjusting for demographic factors and mental-health problems.

RESULTS

The overall prevalence of mental illness in the childhood maltreatment group was significantly higher than in the no childhood maltreatment group (56.1 % vs. 38.2 %, p = 0.017). The maltreated group had a higher rate of major depressive disorder, a higher level of emotional dysregulation, and a lower level of resilience than the group that was not maltreated. Recidivism was uniquely associated with physical neglect (Adjusted Odds Ratio [AOR], 2.862; 95 % Confidence Interval [95 % CI], 1.213-6.752) and the presence of at least one psychiatric disorder (AOR, 3.791; 95 % CI, 1.703-8.443).

CONCLUSIONS

Childhood maltreatment deserves further attention in adult probationers because it is potentially associated with higher rates of psychiatric morbidity and recidivism. In particular, physical neglect during childhood plays a critical role in repeated crime, independent of mental-health problems for high-risk adults involved with the criminal justice system. Rigorous evaluations of the relevance of childhood maltreatment in the assessment and treatment of criminal offenders are needed.

The neurobiological basis of human aggression: A review on genetic and epigenetic mechanisms

Aggression is an evolutionary conserved behavior present in most species including humans. Inadequate aggression can lead to long-term detrimental personal and societal effects. Here, we differentiate between proactive and reactive forms of aggression and review the genetic determinants of it. Heritability estimates of aggression in general vary between studies due to differing assessment instruments for aggressive behavior (AB) as well as age and gender of study participants. In addition, especially non-shared environmental factors shape AB. Current hypotheses suggest that environmental effects such as early life stress or chronic psychosocial risk factors (e.g., maltreatment) and variation in genes related to neuroendocrine, dopaminergic as well as serotonergic systems increase the risk to develop AB. In this review, we summarize the current knowledge of the genetics of human aggression based on twin studies, genetic association studies, animal models, and epigenetic analyses with the aim to differentiate between mechanisms associated with proactive or reactive aggression. We hypothesize that from a genetic perspective, the aminergic systems are likely to regulate both reactive and proactive aggression, whereas the endocrine pathways seem to be more involved in regulation of reactive aggression through modulation of impulsivity. Epigenetic studies on aggression have associated non-genetic risk factors with modifications of the stress response and the immune system. Finally, we point to the urgent need for further genome-wide analyses and the integration of genetic and epigenetic information to understand individual differences in reactive and proactive AB. © 2015 Wiley Periodicals, Inc.

Aggressive behavior in humans: Genes and pathways identified through association studies

Aggressive behavior has both genetic and environmental components. Many association studies have been performed to identify genetic factors underlying aggressive behaviors in humans. In this review we summarize the previous work performed in this field, considering both candidate gene (CGAS) and genome-wide association studies (GWAS), excluding those performed in samples where the primary diagnosis is a psychiatric or neurological disorder other than an aggression-related phenotype. Subsequently, we have studied the enrichment of pathways and functions in GWAS data. The results of our searches show that most CGAS have identified associations with genes involved in dopaminergic and serotonergic neurotransmission and in hormone regulation. On the other hand, GWAS have not yet identified genome-wide significant associations, but top nominal findings are related to several signaling pathways, such as axon guidance or estrogen receptor signaling, and also to neurodevelopmental processes and synaptic plasticity. Future studies should use larger samples, homogeneous phenotypes and standardized measurements to identify genes that underlie aggressive behaviors in humans. © 2016 Wiley Periodicals, Inc.

Genetics of aggressive behavior: An overview

The Research Domain Criteria (RDoC) address three types of aggression: frustrative non-reward, defensive aggression and offensive/proactive aggression. This review sought to present the evidence for genetic underpinnings of aggression and to determine to what degree prior studies have examined phenotypes that fit into the RDoC framework. Although the constructs of defensive and offensive aggression have been widely used in the animal genetics literature, the human literature is mostly agnostic with regard to all the RDoC constructs. We know from twin studies that about half the variance in behavior may be explained by genetic risk factors. This is true for both dimensional, trait-like, measures of aggression and categorical definitions of psychopathology. The non-shared environment seems to have a moderate influence with the effects of shared environment being unclear. Human molecular genetic studies of aggression are in an early stage. The most promising candidates are in the dopaminergic and serotonergic systems along with hormonal regulators. Genome-wide association studies have not yet achieved genome-wide significance, but current samples are too small to detect variants having the small effects one would expect for a complex disorder. The strongest molecular evidence for a genetic basis for aggression comes from animal models comparing aggressive and non-aggressive strains or documenting the effects of gene knockouts. Although we have learned much from these prior studies, future studies should improve the measurement of aggression by using a systematic method of measurement such as that proposed by the RDoC initiative.

An overview of the neurobiology of suicidal behaviors as one meta-system

Suicidal behaviors (SB) may be regarded as the outmost consequence of mental illnesses, or as a distinct entity per se. Regardless, the consequences of SB are very large to both society and affected individuals. The path leading to SB is clearly a complex one involving interactions between the subject's biology and environmental influences throughout life. With the aim to generate a representative and diversified overview of the different neurobiological components hypothesized or shown implicated across the entire SB field up to date by any approach, we selected and compiled a list of 212 gene symbols from the literature. An increasing number of novel gene (products) have been introduced as candidates, with half being implicated in SB in only the last 4 years. These candidates represent different neuro systems and functions and might therefore be regarded as competing or redundant explanations. We then adopted a unifying approach by treating them all as parts of the same meta-system, using bioinformatic tools. We present a network of all components connected by physical protein-protein interactions (the SB interactome). We proceeded by exploring the differences between the highly connected core (~30% of the candidate genes) and its peripheral parts, observing more functional homogeneity at the core, with multiple signal transduction pathways and actin-interacting proteins connecting a subset of receptors in nerve cell compartments as well as development/morphology phenotypes and the stress-sensitive synaptic plasticity processes of long term potentiation/depression. We suggest that SB neurobiology might also be viewed as one meta-system and perhaps be explained as intrinsic unbalances acting within the core or as imbalances arising between core and specific peripheral components.

Potential neurochemical links between cholesterol and suicidal behavior

The role of cholesterol in psychiatric diseases has aroused the interest of the medical community, particularly in association with violent and suicidal behavior. Herein, we discuss some aspects of brain cholesterol metabolism, exploring possible mechanisms underlying the findings and reviewing the available literature on the possible neurochemical link between suicide and low or reduced levels of serum cholesterol. Most of the current hypotheses suggest a decreased serotonergic activity due to a decrease in cholesterol in the lipid rafts of synaptic membranes. Some aspects and limitations of this assumption are emphasized. In addition to serotonin hypofunction, other mechanisms have been proposed to explain increased impulsivity in suicidal individuals, including steroid modulation and brain-derived neurotrophic factor decrease, which could also be related to changes in lipid rafts. Other putative markers of suicidal behavior (e.g. protein S100B) are discussed in connection with cholesterol metabolism in the brain tissue.

Plasma total cholesterol in psychiatric patients after a suicide attempt and in follow-up

BACKGROUND

Low plasma total cholesterol (TC) levels have been found in subjects after a suicide attempt in most studies. Other studies question these results because of possible influences on TC of somatic effects due to the attempt (drugs, somatic trauma, hospitalization), or nutritional habits and physical activity before attempt, especially in patients with depression.

METHODS

To address this issue, TC levels were estimated in 51 subjects on admission to psychiatric clinic after a suicide attempt, as well as later in follow-up when patients were back in their normal activities. Patients were evaluated for suicide intent (SIS), aggression, and severity of depression (BDI).

RESULTS

A small (7% in the mean) but statistically significant increase in plasma cholesterol levels was observed in samples taken in follow-up compared to samples after attempt. However, TC levels of patients were significantly lower than controls in both assessments. There were no differences in TC between violent and non-violent attempters, either after attempt or in follow-up. In the subgroup of patients with major affective disorder, TC levels were lower compared to age-matched controls in both assessments, although patients showed significant reductions in BDI score in follow-up. In this subgroup, TC levels after attempt correlated negatively to SIS score.

CONCLUSIONS

TC levels in psychiatric patients after a suicide attempt are lower than healthy controls and remain low in follow-up, independently from the severity of psychopathology. The results support the role of plasma total cholesterol as a biological risk factor in suicidal behavior, especially in affective patients.

Losing your inhibition: linking cortical GABAergic interneurons to schizophrenia

GABAergic interneurons of the cerebral cortex (cINs) play crucial roles in many aspects of cortical function. The diverse types of cINs are classified into subgroups according to their morphology, intrinsic physiology, neurochemical markers and synaptic targeting. Recent advances in mouse genetics, imaging and electrophysiology techniques have greatly advanced our efforts to understand the role of normal cIN function and its dysfunction in neuropsychiatric disorders. In schizophrenia (SCZ), a wealth of data suggests that cIN function is perturbed, and that interneuron dysfunction may underlie key symptoms of the disease. In this review, we discuss the link between cINs and SCZ, focusing on the evidence for GABAergic signaling deficits from both SCZ patients and mouse models.

Aggressiveness in different presentations of cluster headache: Results from a controlled multicentric study

Background: The hypothalamus has been discussed as a pivotal structure for both cluster headache (CH) and aggressiveness, but little is known about the extent of self-reported aggressiveness in patients with CH.

Patients and methods: Twenty-six patients with chronic, 25 with active episodic and 22 with episodic CH outside the active period were examined interictally with a validated questionnaire quantifying factors of aggression and compared with 24 migraine patients and 31 headache-free volunteers.

Results: The ANOVA was significant for the subscale ‘self-aggression/depression’ ( F4, 123 = 5.771, p < 0.001) with significant differences between chronic and episodic CH and healthy volunteers. No significant changes were found for other subscales and the sum scale ( F4, 123 < 1.421, p > 0.230). Especially in the clinically most affected group of patients (chronic CH and active episodic CH), high levels of “self-aggression/depression” correlate with higher prevalence of depressive symptoms and higher impairment measured on an emotional and functional level.

Discussion: Self-aggressive and depressive cognitions with highest scores in chronic CH seem to be reactive as they correlate with depressive symptoms and impairment. They should be considered as an important therapeutic target since they impair the patient’s life significantly.

Predicting self- and other-directed violence among discharged psychiatric patients: the roles of anger and psychopathic traits

BACKGROUND

We examined the extent to which trait anger and psychopathic traits predicted post-discharge self-directed violence (SDV) and other-directed violence (ODV) among psychiatric patients.

METHOD

Participants were 851 psychiatric patients sampled from in-patient hospitals for the MacArthur Violence Risk Assessment Study (MVRAS). Participants were administered baseline interviews at the hospital and five follow-up interviews in the community at approximately 10-week intervals. Psychopathy and trait anger were assessed with the Psychopathy Checklist: Screening Version (PSC:SV) and the Novaco Anger Scale (NAS) respectively. SDV was assessed during follow-ups with participants and ODV was assessed during interviews with participants and collateral informants. Psychopathy facets and anger were entered in logistic regression models to predict membership in one of four groups indicating violence status during follow-up: (1) SDV, (2) ODV, (3) co-occurring violence (COV), and (4) no violence.

RESULTS

Anger predicted membership in all three violence groups relative to a non-violent reference group. In unadjusted models, all psychopathy facets predicted ODV and COV during follow-up. In adjusted models, interpersonal and antisocial traits of psychopathy predicted membership in the ODV group whereas only antisocial traits predicted membership in the COV group.

CONCLUSIONS

Although our results provide evidence for a broad role for trait anger in predicting SDV and ODV among discharged psychiatric patients, they suggest that unique patterns of psychopathic traits differentially predict violence toward self and others. The measurement of anger and facets of psychopathy during discharge planning for psychiatric patients may provide clinicians with information regarding risk for specific types of violence.

Risk and protective genetic variants in suicidal behaviour: association with SLC1A2, SLC1A3, 5-HTR1B &NTRK2 polymorphisms

Background

Suicidal behaviour is known to aggregate in families. Patients with psychiatric disorders are at higher risk for suicide attempts (SA), however protective and risk genetic variants for suicide appear to be independent of underlying psychiatric disorders. Here we investigate genetic variants in genes important for neurobiological pathways linked to suicidal behaviour and/or associated endophenotypes, for association with SA among patients with co-existing psychiatric illness. Selected gene-gene and gene-environment interactions were also tested.

Methods

DNA was obtained from bloods of 159 patients (76 suicide attempters and 83 non-attempters), who were profiled for DSM-IV Axis I psychiatric diagnosis. Twenty-eight single nucleotide polymorphisms (SNPs) from 18 candidate genes (COMT, 5-HT2A, 5-HT1A, 5-HTR1B, TPH1, MAO-A, TPH2, DBH, CNR1, BDNF, ABCG1, GABRA5, GABRG2, GABRB2, SLC1A2, SLC1A3, NTRK2, CRHR1) were genotyped. Genotyping was performed by KBioscience. Tests of association between genetic variants and SA were conducted using Chi squared and Armitage Trend tests. Binary logistical regression analyses were performed to evaluate the contribution of individual genetic variants to the prediction of SA, and to examine SNPs for potential gene-gene and gene-environment interactions.

Results

Our analysis identified 4 SNPs (rs4755404, rs2269272, rs6296 and rs1659400), which showed evidence of association with SA compared to a non-attempter control group. We provide evidence of a 3-locus gene-gene interaction, and a putative gene-environment interaction, whereby genetic variation at the NTRK2 locus may moderate the risk associated with history of childhood abuse.

Conclusion

Preliminary findings suggest that allelic variability in SLC1A2/3, 5-HTR1B and NTRK2 may be relevant to the underlying diathesis for suicidal acts.

A polymorphism in the ABCG1 promoter is functionally associated with coronary artery disease in a Chinese Han population

OBJECTIVE

In this study, we examine the association of single nucleotide polymorphisms (SNPs) of the human ATP binding cassette transporter G1 (ABCG1) gene with atherosclerotic coronary artery disease (CAD) in a Chinese Han population.

METHODS

1021 patients with CAD and 1013 unaffected control subjects were enrolled. PCR-based ligation detection reaction (PCR-LDR) method was used to genotype four SNPs of ABCG1, three (rs2234714, rs2234715 and rs57137919) in the promoter region and one (rs1044317) in the 3'-untranslated region (UTR).

RESULTS

The human ABCG1 -367G>A polymorphism (rs57137919) showed a significantly decreased risk for CAD and myocardial infarction (MI) in a dominant model (adjusted OR = 0.73, p = 0.033 for CAD, and adjusted OR = 0.65, p = 0.014 for MI, respectively). The rs57137919 also showed an association with angiographic severity of CAD (multi-vessel vs. single-vessel CAD, adjusted OR = 0.40, p = 0.005). The findings were further supported by luciferase reporter assay, in which the polymorphism impaired reporter gene expression. The ABCG1 -768G>A polymorphism (rs2234714) showed an association with CAD in a recessive model (adjusted OR = 0.64, p = 0.015), but did not demonstrate a functional influence on reporter gene expression in the luciferase reporter assay.

CONCLUSIONS

The SNP rs57137919 in the ABCG1 promoter region is functionally associated with a reduced risk of CAD in a Chinese Han population.

Childhood physical abuse, aggression, and suicide attempts among criminal offenders

Childhood physical abuse (CPA) has numerous short and long-term negative effects. One of the most serious consequences of CPA is an increased risk for suicide attempts. Clarifying the mechanisms by which CPA increases risk for suicidal behavior may enhance preventive interventions. One potential mechanism is a tendency toward aggression. In a sample of 266 criminal offenders, ages 18-62, we examined the relationships among CPA, lifetime aggression, and suicide attempts and tested lifetime history of aggression as a mediator of the relationship between CPA and suicide attempts. Results indicated that CPA and aggression were associated with suicide attempts. Consistent with our hypothesis, lifetime aggression mediated the CPA and suicide attempts relationship. Findings suggest that aggression may be an important mediator of the relationship between CPA and suicide attempts among criminal offenders, and are consistent with the possibility that treating aggression may reduce risk for suicide attempts.

Labile anger during interferon alfa treatment is associated with a polymorphism in tumor necrosis factor alpha

OBJECTIVE

Inflammatory cytokines may influence both labile anger and depression. Both psychiatric conditions can occur during interferon alfa-based treatments. Evidence also indicates a central nervous system role for tumor necrosis factor alpha (TNF-alpha), whose expression may be increased by interferon alfa. A polymorphism in the promoter region of TNF-alpha has been associated with various inflammatory illnesses. We therefore hypothesized that this TNF-alpha polymorphism would influence susceptibility to psychiatric symptoms during interferon alfa therapy.

METHODS

One hundred five patients with hepatitis C, initially without active major depression (major depressive disorder), were treated with interferon alfa and then prospectively monitored using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, the Beck Depression Inventory II, the Anger Irritability and Assault Questionnaire, and circulating TNF-alpha levels. The A-308G polymorphism (rs1800629) was determined using the 5'-nuclease assay. Repeated-measure mixed-effect analyses compared changes in symptoms over time.

RESULT

Beck Depression Inventory II score increased during interferon alfa therapy (F = 6.2; P < 0.001), with 27% developing MDD. The TNF-alpha A allele was associated with worsened labile anger (F = 2.5; P < 0.05) and fatigue (F = 2.9; P < 0.05) during treatment but not with major depression incidence (chi = 0.0; P = 0.99) or increased Beck Depression Inventory II (F = 1.2; P = 0.31). Labile anger was not predicted by the serotonin transporter polymorphism (F = 0.8; P = 0.59).

DISCUSSION

During treatment with an exogenous cytokine, vulnerability to worsening labile anger-distinct from major depression-is associated with genetic variability in TNF-alpha. This has implications both for patients being treated with interferon alfa and our understanding of genetic vulnerability for different subtypes of dysphoric and mood disorders.

Total serum cholesterol levels and suicide attempts in child and adolescent psychiatric inpatients

Associations between cholesterol and suicidal behavior in adolescent patients have not been explored in depth. In this study, 66 patients consecutively admitted to a psychiatric inpatient unit following attempted suicide were compared with a control group of 54 patients with no history of suicide attempts. The age range of the sample was from 8 to 18 years old. Cholesterol levels were significantly lower in attempted suicide patients than in controls (p < 0.02), supporting the hypothesis that lower cholesterol levels might be associated with suicidal behavior in patients with similar acute phase of their disorder.

Aggression is related to frontal serotonin-1A receptor distribution as revealed by PET in healthy subjects

OBJECTIVES

Various studies indicate that serotonin regulates impulsivity and the inhibitory control of aggression. Aggression is also known to be modified by sex hormones, which exert influence on serotonergic neurotransmission. The present study aimed to elucidate potential interactions between human aggression, the inhibitory serotonergic 5-HT(1A) receptor, and sex hormones.

EXPERIMENTAL DESIGN

Thirty-three healthy volunteers (16 women, aged 26.24 +/- 5.5 yr) completed a validated questionnaire incorporating five dimensions of aggression. Subsequently, all subjects underwent positron emission tomography with the radioligand [carbonyl-(11)C]WAY-100635 to quantify 5-HT(1A) binding potentials (BP(ND)s) in the prefrontal cortex, limbic areas, and midbrain. Also, plasma levels of testosterone, 17beta-estradiol and sex hormone-binding globulin (SHBG) were measured. Relations between aggression scores, regional 5-HT(1A) BP(ND)s, and hormone levels were analyzed using correlations, multivariate analyses of variance, and linear regressions.

PRINCIPAL OBSERVATIONS

Statistical analyses revealed higher 5-HT(1A) receptor BP(ND)s in subjects exhibiting higher aggression scores in prefrontal (all P < 0.041) and anterior cingulate cortices (P = 0.016). More aggressive subjects were also characterized by lower SHBG levels (P = 0.015). Moreover, higher SHBG levels were associated with lower 5-HT(1A) BP(ND)s in frontal (P = 0.048) and cingulate cortices (all P < 0.013) and in the amygdala (P = 0.03).

CONCLUSIONS

The present study provides first-time evidence for a specific interrelation between the 5-HT(1A) receptor distribution, sex hormones, and aggression in humans. Our findings point to a reduced down-stream control due to higher amounts or activities of frontal 5-HT(1A) receptors in more aggressive subjects, which is presumably modulated by sex hormones.

The genetics of suicide: a critical review of molecular studies

Genetic epidemiology research has shown that genes contribute to suicide risk. Unfortunately, the first 30 years of candidate-based association studies have provided little information about the specific genetic contributors. This article reviews genetic association studies of suicidal phenotypes published to date. Possible theoretical, methodological, and operational challenges accounting for the modest success of association studies in the field are also discussed. The authors conclude that future research may benefit from using a more systematic and comprehensive selection of candidate genes and variants, examining gene-environment and gene-gene interactions, and investigating higher-order moderators.