Aggressive behavior, related conduct problems, and variation in genes affecting dopamine turnover

Neuroimaging and Brain-Based Markers Identifying Neurobiological Markers Associated With Criminal Behaviour, Personality Disorders, and Mental Health: A Narrative Review

We begin the review by pointing to the common stigma associated with mental health issues, which often derives from a lack of understanding or incomplete knowledge. Neurobiological research provides us with a new lens to help challenge and dispel common assumptions and misunderstandings and gives an understanding of sexual behaviours that influence society. As such, it generates substantial evidence for the structural and functional asymmetry of the brains of individuals with mental disorders. However, this type of representation poses many challenges to traditional thinking and constantly provokes change in perspective and empathy towards those individuals. In the review, we go deeper into the effects of neurobiological findings on understanding criminal behaviours and personality disorders, looking further beyond behavioural health. These problems, which were once mainly discussed as moral ones or viewed from the perspective of character flaws, are analysed today through neurological considerations pointing to their complexity. When the root of bipolar disorder is revealed to be neurological, society will react with more information and understanding, hence reducing the stigmatisation and discrimination meted out to people with these problems. At a macro level, findings from neurobiology affect society in ways that go beyond individuals; social attitudes, laws, and policies about the services rendered are influenced. Operating as a catalyst within the community, neurobiological research helps to initiate social change through the creation of an informed, understanding public forum. Thus, it creates broader value for those dealing with behavioural and mental health challenges. The first and most important question of this narrative review is focused on identifying identifiable neurobiological markers that are closely related to criminal conduct, personality disorders, and mental health disorders. Through this review, we aim to present detailed insights into the neurological foundations that anchor these phenomena via a narrative analysis of contemporary literature. The potential implications are finding problems early to apply specific treatment and learning an advanced strategy for social attitudes. This will promote a more humanistic approach based on adequate information on the behavioural and mental health issues involved.

Treatment of Aggression in Adults with Autism Spectrum Disorder: A Review

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by markedly impaired social interaction, impaired communication, and restricted/repetitive patterns of behavior, interests, and activities. In addition to challenges caused by core symptoms, maladaptive behaviors such as aggression can be associated with ASD and can further disrupt functioning and quality of life. For adults with ASD, these behaviors can portend adverse outcomes (e.g., harm to others or to the individual with ASD, hindering of employment opportunities, criminal justice system involvement). This article reviews the scientific literature to provide an update on evidence-based interventions for aggression in adults with ASD.

METHOD

A search of the electronic databases CINAHL, EMBASE, and PsycINFO was conducted using relevant search terms. After reviewing titles, abstracts, full-length articles, and reference lists, 70 articles were identified and reviewed.

RESULTS

The strongest (controlled trial) evidence suggests beneficial effects of risperidone, propranolol, fluvoxamine, vigorous aerobic exercise, and dextromethorphan/quinidine for treating aggression in adults with ASD, with lower levels of evidence supporting behavioral interventions, multisensory environments, yokukansan, and other treatments.

CONCLUSIONS

Additional randomized, controlled trials using consistent methodology that adequately addresses sources of bias are needed to determine which treatments are reliably effective in addressing aggression in adults with ASD. In the meantime, considering efficacy and adverse effect/long-term risk profiles, a practical approach could start with functional assessment-informed behavioral interventions along with encouragement of regular, vigorous aerobic exercise to target aggression in adults with ASD, with pharmacotherapy employed if these interventions are unavailable or inadequate based on symptom acuity.

Differences in SNP genotype distributions between complex and simple suicides

Dysregulations in serotonin neurotransmission can be a strong contributing factor in suicide and impulsive-aggressive personality traits. Victims of suicide form a heterogeneous group in terms of planning, lethality and number of used methods. In this study, we tested single nucleotide polymorphisms (SNPs) of the monoamine oxidase (MAO) A and B genes on the Slovenian population, which has one of the highest suicide rates in the world. Genotyping was performed on 77 victims of complex suicide, 406 victims of simple suicide and 289 controls. The differences in allele distribution were investigated with the two-tailed χ2 test. Haplotype analysis was performed on 740 subjects. Significant or tendency for significant differences in distribution was observed for all studied polymorphisms in the MAOA gene when comparing male victims of complex suicide, victims of simple suicide and controls. Minor allele frequencies in male victims of complex suicide were A 6.7% for rs3027407, C 13% for rs909525 and T 12.7% for rs1137070; in victims of simple suicide, A 36.3% for rs3027407, C 39.5% for rs909525 and T 36.4% for rs1137070; and in controls, A 25.2% for rs3027407, C 30.4% for rs909525 and T 25.8% for rs1137070. The distribution analysis of polymorphism rs1799836 in the MAOB gene and all studied polymorphisms in the MAOA gene in females failed to show any significant results. GTC haplotype (for rs3027407, rs909525, rs1137070) in MAOA polymorphisms was more frequent in victims of complex suicide compared to that in controls and victims of simple suicide. Compared to victims of complex suicide, male victims of simple suicide were more often carriers of MAOA alleles that are, according to literature, associated with higher levels of impulsivity and anger. These differences in SNP distribution could serve as an additional method of differentiating between victims of complex and victims of simple suicide. Further studies including psychological autopsies should be carried out in order to identify personality traits and behavioural differences among distinct groups of suicide victims.

Some Metatheoretical Principles for Personality Neuroscience

Theories in personality neuroscience must aim to be consistent with several levels of explanation. If we view personality traits as constructs located only at the psychological level, we must still make their explanations compatible with observations and theories at lower levels, particularly with what we know at the neural level. If we view personality traits as constructs located only at the neural level, we will still need to predict their emergent effects at the psychological level. Personality theory at present treats traits as psychological-level constructs, with even the recent neurally oriented Cybernetic Big Five Theory specified in terms of a "conceptual nervous system" and not requiring complete or immediate translation into neural mechanisms. Here, we argue for the existence of phylogenetically old, neural-level traits that are substantially conserved across many vertebrate species. We first ask what known mechanisms control trait-like properties of neural systems: Focusing on hormones, the GABAA receptor, and amine neurotransmitter systems. We derive from what we know about these sources of neuronal modulation some metatheoretical principles to guide the future development of those aspects of personality theory, starting with neural-level trait constructs and drawing implications for higher-level trait psychology observations. Current descriptive approaches such as the Big Five are an essential precursor to personality neuroscience, but may not map one-to-one to the mechanisms and constructs of a neuroscience-based approach to traits.

Risk assessment of aggressive behavior in Chinese patients with schizophrenia by fMRI and COMT gene

BACKGROUND

Blood-oxygen-level dependent functional magnetic resonance imaging (BOLD-fMRI) maps cerebral activity by the hemodynamic response. Catechol-O-methyltransferase (COMT) gene is involved in the metabolism of dopamine. It is reported that both of these can be used to assess the aggression risk in patients with schizophrenia. However, these methods to assess the aggression risk patients with schizophrenia have not been established in China. Therefore, we deliver here a systematic review and meta-analysis based on the studies dealing with Chinese patients.

METHOD

Nine fMRI studies and 12 gene studies were included. The data of each study were extracted and summarized. Odds ratios with 95% confidence intervals were estimated on allele, dominant, and recessive models. Publication bias was evaluated by Begg's funnel plot.

RESULTS

Positive BOLD-fMRI values in the lower central neural system (CNS) and negative values in the high-level CNS were observed in the patients with aggression risk. A strong association was derived from the recessive gene model of COMT polymorphism rs4680 and risk in aggression behavior (odds ratio =2.10). No significant publication bias was identified.

CONCLUSION

Aggression behavior in patients with schizophrenia can be indicated by positive BOLD-fMRI values in the lower CNS and negative values in the high-level CNS and by a recessive gene model in COMT polymorphism rs4680. A combined test of fMRI and COMT gene could increase the predictive value.

Exploring possible association between DβH genotype (C1021T), early onset of conduct disorder and psychopathic traits in juvenile delinquents

Early onset of conduct disorder (CD) with callous-unemotional traits has been linked to low levels of dopamine β-hydroxylase (DβH), an enzyme involved in dopamine turnover. The C1021T polymorphism in the DβH gene is a major quantitative-trait locus, regulating the level of DβH. In this study of juvenile delinquents from Northern Russia (n = 180), the polymorphism at -1021 was associated neither with early-onset CD nor with psychopathic traits. Association was found between psychopathic traits and early-onset CD, ADHD and mania.

Hypothesizing Molecular Genetics of the Holocaust: Were Dopaminergic Genes Involved or Brain Wash?

Numerous studies indicated that the prevalence of certain alleles of the dopamine D2 receptor gene (DRD2) vary across different ethnic groups. Under adverse environmental conditions, these alleles can increase the risk of developing psychiatric symptoms. Thus, we hypothesized that the prevalence of the DRD2 gene Taq IA allele may serve to explain the horrific behaviours practiced by the Nazi regime. Hitler's 'Brain Washing' methods goaded his followers to carry out genocide at a time when carriers of the DRD2 TaqIA allele (the so called 'aggressive--genotype') were significantly higher among the Aryan Germans compared to resident German Jews. It would be of interest, to genotype the Jewish Holocaust survivors, to determine whether those with the Taq AI allele survived in greater numbers. The hypothesis being that, greater survival may result in enhanced frequency of not only the DRD2 AI allele but other reward gene polymorphisms among survivors. Understanding the molecular genetics of any population in terms of reward dependence and subsequent behaviours will be most beneficial in future human interaction whether negative (war) or positive (peace) in nature.

Understanding Persistence and Desistance in Crime and Risk Behaviors in Adulthood: Implications for Theory and Prevention

Recent theoretical advances related to the development and course, including persistence and desistance, of antisocial behaviors and conduct problems, violent behaviors, and related problem behaviors are discussed. Integrative theoretical models, including the Dynamic Developmental Systems (DDS), are discussed. Aspects of the DDS model regarding the development of and change in antisocial behavior and violence across adolescence and early adulthood are illustrated with findings from the Oregon Youth Study, an ongoing, long-term examination of the causes and consequences of antisocial behavior for a community-based sample of men (and their romantic partners) who were raised in neighborhoods with high delinquency rates. Preventive implications of the model are discussed.

Polymorphism in the serotonin receptor 2a (HTR2A) gene as possible predisposal factor for aggressive traits

Aggressive manifestations and their consequences are a major issue of mankind, highlighting the need for understanding the contributory factors. Still, aggression-related genetic analyses have so far mainly been conducted on small population subsets such as individuals suffering from a certain psychiatric disorder or a narrow-range age cohort, but no data on the general population is yet available. In the present study, our aim was to identify polymorphisms in genes affecting neurobiological processes that might explain some of the inter-individual variation between aggression levels in the non-clinical Caucasian adult population. 55 single nucleotide polymorphisms (SNP) were simultaneously determined in 887 subjects who also filled out the self-report Buss-Perry Aggression Questionnaire (BPAQ). Single marker association analyses between genotypes and aggression scores indicated a significant role of rs7322347 located in the HTR2A gene encoding serotonin receptor 2a following Bonferroni correction for multiple testing (p = 0.0007) both for males and females. Taking the four BPAQ subscales individually, scores for Hostility, Anger and Physical Aggression showed significant association with rs7322347 T allele in themselves, while no association was found with Verbal Aggression. Of the subscales, relationship with rs7322347 was strongest in the case of Hostility, where statistical significance virtually equaled that observed with the whole BPAQ. In conclusion, this is the first study to our knowledge analyzing SNPs in a wide variety of genes in terms of aggression in a large sample-size non-clinical adult population, also describing a novel candidate polymorphism as predisposal to aggressive traits.

Gene variants associated with antisocial behaviour: a latent variable approach

OBJECTIVE

The aim of this study was to determine if a latent variable approach might be useful in identifying shared variance across genetic risk alleles that is associated with antisocial behaviour at age 15 years.

METHODS

Using a conventional latent variable approach, we derived an antisocial phenotype in 328 adolescents utilizing data from a 15-year follow-up of a randomized trial of a prenatal and infancy nurse-home visitation programme in Elmira, New York. We then investigated, via a novel latent variable approach, 450 informative genetic polymorphisms in 71 genes previously associated with antisocial behaviour, drug use, affiliative behaviours and stress response in 241 consenting individuals for whom DNA was available. Haplotype and Pathway analyses were also performed.

RESULTS

Eight single-nucleotide polymorphisms (SNPs) from eight genes contributed to the latent genetic variable that in turn accounted for 16.0% of the variance within the latent antisocial phenotype. The number of risk alleles was linearly related to the latent antisocial variable scores. Haplotypes that included the putative risk alleles for all eight genes were also associated with higher latent antisocial variable scores. In addition, 33 SNPs from 63 of the remaining genes were also significant when added to the final model. Many of these genes interact on a molecular level, forming molecular networks. The results support a role for genes related to dopamine, norepinephrine, serotonin, glutamate, opioid and cholinergic signalling as well as stress response pathways in mediating susceptibility to antisocial behaviour.

CONCLUSIONS

This preliminary study supports use of relevant behavioural indicators and latent variable approaches to study the potential 'co-action' of gene variants associated with antisocial behaviour. It also underscores the cumulative relevance of common genetic variants for understanding the aetiology of complex behaviour. If replicated in future studies, this approach may allow the identification of a 'shared' variance across genetic risk alleles associated with complex neuropsychiatric dimensional phenotypes using relatively small numbers of well-characterized research participants.

Influence of prenatal iron deficiency and MAOA genotype on response to social challenge in rhesus monkey infants

Social and emotional behaviors are known to be sensitive to both developmental iron deficiency (ID) and monoamine oxidase A (MAOA) gene polymorphisms. In this study, male rhesus monkey infants deprived of dietary iron in utero were compared with iron sufficient (IS) controls (n = 10/group). Half of each group had low MAOA activity genotypes and half had high MAOA activity genotypes. A series of social response tests were conducted at 3-14 months of age. MAOA genotype influenced attention to a video of aggressive behavior, emotional expression (fear, grimace and sniff) in the social intruder test, social actions (displacement, grooming) in the social dyad test, and aggressive responses to a threatening picture. Interactions between MAOA and prenatal ID were seen in response to the aggressive video, in temperament ratings, in affiliative behavior in the social dyad test, in cortisol response in the social buffering test and in response to a social intruder and to pictures with social and nonsocial themes. In general, the effects of ID were dependent on MAOA genotype in terms of both direction and size of the effect. Nutrition/genotype interactions may shed new light on behavioral consequences of nutritional deprivation during brain development.