Underlying Mechanisms of Gene-Environment Interactions in Externalizing Behavior: A Systematic Review and Search for Theoretical Mechanisms

COMT Val158Met polymorphism protects the impact of a mother's history of childhood trauma on emotional and behavioural problems in preschool children

Childhood trauma has a well-established negative impact on mental health outcomes across the lifespan. Cumulative evidence suggests an intergenerational transmission of trauma to descendants. In this way, considering the child's COMT Val158Met (rs4680: G > A) variant, the study aims to investigate the interactive effect of maternal childhood trauma on the emotional/behavioural problems of their offspring in preschoolers age (4-5 and 11 years old) from a population-based dyad of pregnant adolescent women. The behaviour problems of 310 children were assessed using the Child Behaviour Checklist (CBCL) instrument, and maternal trauma was assessed with the Child Trauma Questionnaire (CTQ) between the 20 to 22° gestational weeks. Maternal childhood trauma increases the risk for all emotional/behavioural problems in the offspring, and no direct association between the child's Val158Met genotypes with emotional/behavioural problems. Interestingly, in moderation analysis adjusted by sex, age and skin colour, children of mothers exposed to childhood trauma, carrying the Val/Met genotype, are less likely to develop externalising (p = .020) and total problems (p = .041) when compared to homozygous (Val/Val and Met/Met). Thus, our findings reinforce evidence on the intergenerational impact of maternal trauma on emotional/behavioural problems and demonstrate that this risk is influenced by the genetic background of the individual, varying according to the functional COMT genotype, which confers a protective profile for the development of externalising and total problems.

Considering heterogeneity within negative emotionality can inform the distinction between diathesis-stress and differential susceptibility: Children's early anger and fear as moderators of effects of parental socialization on antisocial conduct

The importance of interactions between child temperament and parenting has been accepted ever since Thomas and Chess (1977) proposed their "goodness-of-fit" construct, but over the last three decades, pertinent research has grown exponentially. Researchers examining child characteristics that can moderate the effects of socialization have tested increasingly complex, nuanced, and sophisticated models, largely inspired by the highly influential frameworks of child plasticity or differential susceptibility (Belsky & Pluess, 2009). Yet, multiple questions remain unsettled. We addressed four such questions as applied to predicting children's observed disregard for rules at age 4.5 in a study of 200 community families from the US Midwest. (a) We examined children's observed negative emotionality at 16 months, most commonly seen as a plasticity "trait," but separating anger and fear proneness, which may differently moderate effects of socialization. (b) We examined two separate aspects of observed parental socialization at age 3, mutually responsive orientation and power assertion. (c) We distinguished analytically diathesis-stress from differential susceptibility. (d) We examined all effects in mother- and father-child relationships. We supported both diathesis-stress and differential susceptibility, depending on the facet of negative emotionality, the aspect of socialization considered, and parental gender, highlighting the nuanced nature of the processes involved.

Genetics of child aggression, a systematic review

Excessive and persistent aggressiveness is the most common behavioral problem that leads to psychiatric referrals among children. While half of the variance in childhood aggression is attributed to genetic factors, the biological mechanism and the interplay between genes and environment that results in aggression remains elusive. The purpose of this systematic review is to provide an overview of studies examining the genetics of childhood aggression irrespective of psychiatric diagnosis. PubMed, PsycINFO, and MEDLINE databases were searched using predefined search terms for aggression, genes and the specific age group. From the 652 initially yielded studies, eighty-seven studies were systematically extracted for full-text review and for further quality assessment analyses. Findings show that (i) investigation of candidate genes, especially of MAOA (17 studies), DRD4 (13 studies), and COMT (12 studies) continue to dominate the field, although studies using other research designs and methods including genome-wide association and epigenetic studies are increasing, (ii) the published articles tend to be moderate in sizes, with variable methods of assessing aggressive behavior and inconsistent categorizations of tandem repeat variants, resulting in inconclusive findings of genetic main effects, gene-gene, and gene-environment interactions, (iii) the majority of studies are conducted on European, male-only or male-female mixed, participants. To our knowledge, this is the first study to systematically review the effects of genes on youth aggression. To understand the genetic underpinnings of childhood aggression, more research is required with larger, more diverse sample sets, consistent and reliable assessments and standardized definition of the aggression phenotypes. The search for the biological mechanisms underlying child aggression will also benefit from more varied research methods, including epigenetic studies, transcriptomic studies, gene system and genome-wide studies, longitudinal studies that track changes in risk/ameliorating factors and aggression-related outcomes, and studies examining causal mechanisms.

COMT Val/Met, stressful life events and externalizing behaviors in youth: A longitudinal study from the ABCD sample

Early adolescence is a crucial time for understanding and detecting the risk factors that may influence youth externalizing/disruptive behaviors and disorders. Previous literature reported evidence that risk factors for disruptive behaviors include catechol-O-methyltransferase (COMT) Val158Met (rs4680) polymorphism and environmental influences. An unanswered question is whether there is a change in these risk factors over stages of youth development. This longitudinal study examines the interaction effect of Val158Met and stressful life events (SLE) on youth externalizing behaviors from ages 9-11. Participants were 2363 children of European ancestry recruited as part of the Adolescent Brain Cognitive Development study. Repeated measures linear mixed models were used to examine the effect of the interaction between Val158Met and SLE (G × E) on disruptive behaviors over development. Externalizing behaviors were analyzed at both baseline and two-year follow-up. Both Val158Met genotype and SLE scores demonstrated significant main effects on disruptive behaviors in youth, and those effects were consistent at both time points. G × E was not associated with externalizing behaviors. Youth who carried the Val allele and/or were exposed to higher SLE consistently had increased externalizing behavior scores. To our knowledge, this is the first study to longitudinally examine the interaction effects of Val158Met and SLE on externalizing behaviors in youth. The results highlight the importance of understanding the genetic and environmental factors underlying externalizing behaviors for better detection of at-risk youth, helping further with early prevention efforts. The findings propose that COMT Val158Met genotype may act as a biomarker for development of novel treatment strategies for disruptive behaviors.

Candidate gene-environment interactions in substance abuse: A systematic review

BACKGROUND

The abuse of psychogenic drugs can lead to multiple health-related problems. Genetic and environmental vulnerabilities are factors in the emergence of substance use disorders. Empirical evidence regarding the gene-environment interaction in substance use is mixed. Summaries of the latest findings from a candidate gene approach will be useful for revealing the significance of particular gene contributions. Thus, we aim to identify different gene-environment interactions in patterns of substance use and investigate whether any effects trend notably across different genders and races.

METHODS

We reviewed published studies, until March 1, 2022, on substance use for candidate gene-environment interaction. Basic demographics of the included studies, target genes, environmental factors, main findings, patterns of gene-environment interaction, and other relevant information were collected and summarized.

RESULTS

Among a total of 44 studies, 38 demonstrated at least one significant interaction effect. About 61.5% of studies on the 5-HTTLPR gene, 100% on the MAOA gene, 42.9% on the DRD2 gene, 50% on the DRD4 gene, 50% on the DAT gene, 80% on the CRHR1 gene, 100% on the OPRM1 gene, 100% on the GABRA1 gene, and 50% on the CHRNA gene had a significant gene-environment interaction effect. The diathesis-stress model represents a dominant interaction pattern (89.5%) in the studies with a significant interaction effect; the remaining significant effect on substance use is found in the differential susceptibility model. The social push and swing model were not reported in the included studies.

CONCLUSION

The gene-environment interaction research on substance use behavior is methodologically multidimensional, which causes difficulty in conducting pooled analysis, or stated differently-making it hard to identify single sources of significant influence over maladaptive patterns of drug taking. In decreasing the heterogeneity and facilitating future pooled analysis, researchers must (1) replicate the existing studies with consistent study designs and measures, (2) conduct power calculations to report gene-environment correlations, (3) control for covariates, and (4) generate theory-based hypotheses with factorial based experiments when designing future studies.

Mood Disorders and Aggressive Traits Mediate Effects of Reported Childhood Adversity on Suicide Attempt Risk

BACKGROUND

Childhood adversity (CA) is linked to suicidal behavior as well as to mood disorders and aggressive traits. This raises the possibility that depression and aggressive traits mediate the relationship of childhood adversity to suicide risk. Moreover, it is not known if they operate independently or interactively.

AIMS

To determine whether, and how, mood disorders and aggressive traits mediate the effects of reported physical and sexual abuse on future suicidal behavior.

METHODS

Five hundred and forty-eight subjects, offspring of parents with mood disorders, were interviewed at baseline and at yearly follow-ups with questionnaires assessing aggression, mood disorders, and suicidal behavior. The mediation analysis involved a three-step process, testing the relationships between (1) CA and attempt; (2) CA and putative mediators; and (3) putative mediators and suicide attempt, adjusting for CA.

RESULTS

Aggressive trait severity and mood disorder onset each mediated the relationship between CA and future suicide attempts. Greater aggression severity also raised the hazard of the development of a mood disorder. If aggressive trait severity was clearly elevated, then onset of mood disorder did not increase further the hazard of the suicide attempt. Including family as a random effect had a much bigger effect on attempt outcome for physical abuse compared with sexual abuse.

CONCLUSIONS

Amelioration of aggressive traits and treatment of mood disorders in CA-exposed offspring of a parent with a mood disorder may prevent future suicide attempts and may reduce the risk of mood disorder. Familial factors influence the impact of childhood physical abuse but not sexual abuse. HIGHLIGHTSChildhood Adversity (CA) predicted future mood disorder and aggression severity.Depression and aggression mediate the relationship between CA and suicide attempts.When one mediator is present, the presence of the other does not increase the hazard.Between family variation contributed much more to suicidal behavior outcomes relative to the effect of physical abuse, but sexual abuse contributed to suicidal outcomes more than family variation.

Probing the genomic landscape of human sexuality: a critical systematic review of the literature

Whether human sexuality is the result of nature or nurture (or their complex interplay) represents a hot, often ideologically driven, and highly polarized debate with political and social ramifications, and with varying, conflicting findings reported in the literature. A number of heritability and behavioral genetics studies, including pedigree-based investigations, have hypothesized inheritance patterns of human sexual behaviors. On the other hand, in most twin, adoption, and nuclear family studies, it was not possible to disentangle between underlying genetic and shared environmental sources. Furthermore, these studies were not able to estimate the precise extent of genetic loading and to shed light both on the number and nature of the putative inherited factors, which remained largely unknown. Molecular genetic studies offer an unprecedented opportunity to overcome these drawbacks, by dissecting the molecular basis of human sexuality and allowing a better understanding of its biological roots if any. However, there exists no systematic review of the molecular genetics of human sexuality. Therefore, we undertook this critical systematic review and appraisal of the literature, with the ambitious aims of filling in these gaps of knowledge, especially from the methodological standpoint, and providing guidance to future studies. Sixteen studies were finally retained and overviewed in the present systematic review study. Seven studies were linkage studies, four studies utilized the candidate gene approach, and five studies were GWAS investigations. Limitations of these studies and implications for further research are discussed.

Associations of the serotonin transporter gene polymorphism, 5-HTTLPR, and adverse life events with late life depression in the elderly Lithuanian population

Late-life depression (LLD) is a multifactorial disorder, with susceptibility and vulnerability potentially influenced by gene-environment interaction. The aim of this study was to investigate whether the 5-HTTLPR polymorphism is associated with LLD. The sample of 353 participants aged 65 years and over was randomly selected from the list of Kaunas city inhabitants by Residents' Register Service of Lithuania. Depressive symptoms were ascertained using the EURO-D scale. The List of Threatening Events Questionnaire was used to identify stressful life events that happened over the last 6 months and during lifetime. A 5-HTTLPR and lifetime stressful events interaction was indicated by higher odds of depression in those with s/s genotype who experienced high stress compared to l/l carriers with low or medium stress, while 5-HTTLPR and current stressful events interaction analysis revealed that carriers of either one or two copies of the s allele had increased odds of depressive symptoms associated with stress compared to participants with the l/l genotype not exposed to stressful situations. Although no significant direct association was found between the 5-HTTLPR short allele and depression, our findings demonstrated that lifetime or current stressful life events and their modification by 5-HTTLPR genotype are risk factors for late-life depression.

Dietary Supplementation with Milk Lipids Leads to Suppression of Developmental and Behavioral Phenotypes of Hyperexcitable Drosophila Mutants

Dietary modifications often have a profound impact on the penetrance and expressivity of neurological phenotypes that are caused by genetic defects. Our previous studies in Drosophila melanogaster revealed that seizure-like phenotypes of gain-of-function voltage-gated sodium (Nav) channel mutants (paraShu, parabss1, and paraGEFS+), as well as other seizure-prone "bang-sensitive" mutants (eas and sda), were drastically suppressed by supplementation of a standard diet with milk whey. In the current study we sought to determine which components of milk whey are responsible for the diet-dependent suppression of their hyperexcitable phenotypes. Our systematic analysis reveals that supplementing the diet with a modest amount of milk lipids (0.26% w/v) mimics the effects of milk whey. We further found that a minor milk lipid component, α-linolenic acid, contributed to the diet-dependent suppression of adult paraShu phenotypes. Given that lipid supplementation during the larval stages effectively suppressed adult paraShu phenotypes, dietary lipids likely modify neural development to compensate for the defects caused by the mutations. Consistent with this notion, lipid feeding fully rescued abnormal dendrite development of class IV sensory neurons in paraShu larvae. Overall, our findings demonstrate that milk lipids are sufficient to ameliorate hyperexcitable phenotypes in Drosophila mutants, providing a foundation for future investigation of the molecular and cellular mechanisms by which dietary lipids modify genetically induced abnormalities in neural development, physiology, and behavior.

Epigenome-wide DNA methylation in externalizing behaviours: A review and combined analysis

DNA methylation (DNAm) is one of the most frequently studied epigenetic mechanisms facilitating the interplay of genomic and environmental factors, which can contribute to externalizing behaviours and related psychiatric disorders. Previous epigenome-wide association studies (EWAS) for externalizing behaviours have been limited in sample size, and, therefore, candidate genes and biomarkers with robust evidence are still lacking. We 1) performed a systematic literature review of EWAS of attention-deficit/hyperactivity disorder (ADHD)- and aggression-related behaviours conducted in peripheral tissue and cord blood and 2) combined the most strongly associated DNAm sites observed in individual studies (p < 10^-3) to identify candidate genes and biological systems for ADHD and aggressive behaviours. We observed enrichment for neuronal processes and neuronal cell marker genes for ADHD. Astrocyte and granulocytes cell markers among genes annotated to DNAm sites were relevant for both ADHD and aggression-related behaviours. Only 1 % of the most significant epigenetic findings for ADHD/ADHD symptoms were likely to be directly explained by genetic factors involved in ADHD. Finally, we discuss how the field would greatly benefit from larger sample sizes and harmonization of assessment instruments.

Added value of neurotechnology for forensic psychiatric and psychological assessment

The attention for neuroscience in relation to criminal behavior is growing rapidly, and research shows that neurobiological factors have added value to the understanding of psychological and social factors in explaining delinquency. There is evidence that neurotechnology can be used in criminal justice and may be of relevance for forensic psychiatric and psychological assessment. However, the question is whether scientific knowledge of neurobiological factors is applicable in daily practice of forensic assessment. Incorporation of basic technologies, e.g., psychophysiology (heart rate, skin conductance, wearables), hormonal measures (cortisol, testosterone), and neuropsychological testing might be evident, since they can be applied relatively easy. Moreover, a body of research shows the additive value of these technologies in this field. In addition, first steps are taken to apply these technologies in individual diagnostics, treatment, and risk assessment. Complex neurotechnologies like functional MRI (e.g., brain reading) and EEG show potential to be applicable in criminal justice, once it is known what additional information these indices offer for individual cases.

Parental rejection in early adolescence predicts a persistent ADHD symptom trajectory across adolescence

Despite a general decrease of attention-deficit/hyperactivity disorder (ADHD) symptoms during adolescence, these may persist in some individuals but not in others. Prior cross-sectional studies have shown that parenting style and their interaction with candidate genes are associated with ADHD symptoms. However, there is a lack of longitudinal research examining the independent and interactive effects of parenting and plasticity genes in predicting the course of attention-deficit/hyperactivity disorder (ADHD) symptoms across adolescence. Here, we investigated how children perceived their parents' parenting style (i.e., rejection, overprotection, and emotional warmth) at the age of 11, and their interaction with DRD4, MAOA, and 5-HTTLPR genotypes on parent-reported ADHD symptoms at three time points (mean ages 11.1, 13.4, and 16.2 years) in 1730 adolescents from the TRacking Adolescents' Individual Lives Survey (TRAILS). Growth Mixture Modeling in Mplus identified four ADHD symptom trajectories: low, moderate stable, high decreasing, and high persistent. Perceived parental rejection predicted class membership in the high persistent trajectory compared to the other classes (p < 0.001, odds ratios between 2.14 and 3.74). Gene-environment interactions were not significantly related to class membership. Our results indicate a role of perceived parental rejection in the persistence of ADHD symptoms. Perceived parental rejection should, therefore, be taken into consideration during prevention and treatment of ADHD in young adolescents.

Examining how and why polygenic dopamine composite levels moderate adolescents' vulnerability to peer victimization

Extensive literature documents that dopaminergic genes play an important role in the link between adverse environments and adolescents' problem behavior. However, little is known about the potential mechanism underlying adolescents' vulnerability to peer victimization. The current study examined the effect of the interplay between a polygenic dopamine composite (i.e., COMT Val158Met and DRD2-141C Ins/Del polymorphisms) and peer victimization on adolescents' externalizing problems as well as the mediating role of emotion dysregulation in the interactive effects in a sample of 393 Chinese adolescents (Mean age = 14.71 years; 50.1% girls). A significant moderation of dopaminergic genetic composite was observed in girls but not in boys. In addition, emotion dysregulation partially explained the moderating effect of dopaminergic genes. Specifically, girls with genic composite indexing low dopamine activity reported a higher level of emotion dysregulation when faced with more peer victimization. More difficulties with emotion regulation, in turn, predicted more pronounced externalizing problems in girls. This study underscores polygenic underpinnings of adolescent vulnerability to negative peer experiences and suggests the importance of considering sex differences when investigating genic influence on the relationship between adverse environments and externalizing problems.

Antipsychotics in the Management of Disruptive Behavior Disorders in Children and Adolescents: An Update and Critical Review

Disruptive behaviour disorders (DBDs) in childhood include conduct disorder (CD) and oppositional defiant disorder (ODD). Though psychological therapies are considered to be the first-line treatment for DBDs, many patients require adjunctive pharmacotherapy for the control of specific symptoms, such as aggression. Three prior systematic reviews have examined the evidence for the use of antipsychotics in DBDs and have concluded that their efficacy is marginal and limited by adverse effects. This paper has two objectives: (i) to summarize the findings of existing systematic reviews of antipsychotics for the management of DBDs in children and adolescents (2012-2017), and (ii) to provide an update to these reviews by examining recent clinical trials of antipsychotics in this population, published in the period from 2 January 2017 to 10 October 2022. The PubMed, Scopus and ScienceDirect databases were searched for relevant citations using the search terms "disruptive behaviour disorder", "oppositional defiant disorder", "conduct disorder" and their variants, along with "antipsychotic", "atypical antipsychotic" and the generic names of all currently approved atypical antipsychotics. Six relevant trials were identified during this period, including five randomized controlled trials and one naturalistic open-label trial. These trials were critically evaluated in terms of outcome measures, efficacy and safety. Overall, the data from these trials suggests that of all available antipsychotics, risperidone appears to be effective in the short-term management of DBDs. All available antipsychotics are associated with significant metabolic adverse effects in this population. These results are discussed in the light of global trends towards increasing off-label prescription of antipsychotic medication in children and adolescents and of recent literature on the neuropharmacology of aggression in this patient population. The need for rational, short-term use of these drugs is highlighted, as well as the importance of post-marketing surveillance for long-term or severe adverse events.

Childhood violence exposure and externalizing behaviors: A systematic review of the role of physiological biomarkers

Childhood exposure to violence has been consistently linked to externalizing behaviors like delinquency and aggression. Growing evidence indicates that physiological biomarkers from the parasympathetic and sympathetic nervous systems (PNS and SNS) and hypothalamic-pituitary-adrenal (HPA) axis may moderate or mediate the relation between childhood violence exposure and externalizing behaviors. We conducted a systematic review to synthesize recent findings on physiological biomarkers as mediators and/or moderators of this association across the life course, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Our search yielded 3878 articles, of which 44 met inclusion criteria (describing a total of 46 independent studies). We found consistent evidence for blunted HPA-axis reactivity as a mediator of the relation between childhood violence exposure and subsequent externalizing behaviors, and for non-reciprocal PNS/SNS activation as moderators exacerbating this relation. However, the results of the majority of included studies that demonstrated significant moderating effects of physiological biomarkers varied by participant sex, type of childhood violence exposure, and type of stimuli used to induce physiological reactivity. The observed mixed findings are consistent with some theories that emphasize that both high and low stress reactivity can be adaptive depending on one's early environment. These findings highlight the need for systematic explorations of heterogeneity, theory-driven research questions, and longitudinal studies that span multiple developmental periods and multiple biological systems. Clinical implications include the need to assess physiological biomarkers in treatment and intervention studies and the potential to target interventions based on both autonomic functioning and environmental contexts.

Longitudinal Influences of DRD4 Polymorphism and Early Maternal Caregiving on Personality Development and Problem Behavior in Middle Childhood and Adolescence

Most studies examining gene-environment effects on self-regulation focus on outcomes early childhood or adulthood. However, only a few studies investigate longitudinal effects during middle childhood and adolescence and compare two domains of early caregiving. In a longitudinal follow-up with a sample of N = 87, we studied the effects of differences in the DRD4 tandem repeat polymorphisms and two domains of early maternal caregiving quality on children's personality development using Block's California Child Q-Set (CCQ) at age six and age 12 and on problem behavior at ages six and seven. Early maternal regulation quality predicted later ego-resiliency and aggressiveness. In addition, significant gene-environment interactions revealed that children with the 7+ DRD4 tandem repeat polymorphism and poor maternal regulation quality in infancy showed lower scores in ego-resiliency and higher scores in ego-undercontrol and CCQ aggressiveness. In contrast, children who had experienced effective maternal regulation in infancy showed a comparable level in personality traits and problem behavior as the DRD4 7- group independent of the levels of maternal regulatory behavior. Similarly, longitudinal caregiving × DRD4 interactions were found for behavior problems in middle childhood, especially for oppositional-aggression, inattentive-hyperactivity, and social competence. Early caregiving effects were only found for maternal regulation quality, but not for maternal responsiveness. Effective early maternal regulation in infancy can moderate the negative effect of DRD4 7+ on children's self-regulation in middle childhood and adolescence. However, maternal responsiveness has no comparable effects. It seems relevant to consider several dimensions of early caregiving and to also measure the environment in more detail in gene-environment studies.

The Role of Psychopathic Traits in Explaining Associations Between Childhood Traumatic Experiences and Aggression

The present study reports on a preregistered investigation of the potential mediating role of the triarchic psychopathy components Boldness, Meanness, and Disinhibition for associations between childhood traumatic experiences (CTE) and aggression. Three nonclinical samples (total N = 1,729; 1,176 women, 68.02%) completed self-report instruments of CTE, triarchic psychopathy traits, reactive and proactive aggression (Samples 1 and 2), and general aggression (Sample 3). Cross-sectional path analyses revealed that both Meanness and Disinhibition consistently mediated associations between CTE and aggression. These indirect effects were consistent across gender, even though the direct effect of Meanness on proactive aggression was stronger in men than in women (Samples 1 and 2). Finally, Boldness had weak negative associations with childhood traumatic experiences in all three samples, but no direct association with aggression. Taken together, these correlational findings suggest potential developmental mechanisms linking early traumatic experiences to adult aggression through elevated levels of psychopathic traits.

The gray matter volume of the temporoparietal junction varies across cultures: a moderating role of the dopamine D4 receptor gene (DRD4)

Prior work shows that compared to European Americans, East Asians show an enhanced propensity to take the perspective of another person. In the current work, we tested whether this cultural difference might be reflected in the gray matter (GM) volume of the temporoparietal junction (TPJ), a brain region selectively implicated in perspective taking and mentalizing. We also explored whether the cultural difference in the TPJ GM volume might be moderated by dopamine D4 receptor gene (DRD4) exon 3 variable-number tandem repeat polymorphism. Structural magnetic resonance imaging of 66 European Americans and 66 East Asian-born Asians were subjected to voxel-based morphometry. It was observed that the GM volume of the right TPJ was greater among East Asians than among European Americans. Moreover, this cultural difference was significantly more pronounced among carriers of the 7- or 2-repeat allele of DRD4 than among the non-carriers of these alleles. Our findings contribute to the growing evidence that culture can shape the brain.

Early childhood psychosocial family risks and cumulative dopaminergic sensitizing score: Links to behavior problems in U.S. 9-year-olds

BACKGROUND

We examined, (a) whether in early childhood exposure to risky family environment in different domains (socioeconomic, mental, parenting practices, health behavior, and child-related risks) and accumulatively across various domains (cumulative risk) is associated with child's problem behavior at age 9, and (b) whether the association is more pronounced in children carrying cumulative dopaminergic sensitizing genotype or living in low-income families.

METHODS

Participants were 2,860 9-year old children (48% females; 48% Black) and their mothers from the 'Fragile Families and Child Wellbeing Study', a probability birth cohort from large U.S. cities. Mothers responded to questions on child's problem behavior (CBCL). Children responded to questions about their vandalism and substance use.

RESULTS

Cumulative family risk was associated with higher internalizing and externalizing behavior and higher vandalism and substance use. All domain-specific risk clusters were associated with higher internalizing behavior and, with the exception of child-related risk, with higher externalizing behavior. Mental health risks, risky parenting practices, and risky health behavior were associated with higher vandalism. Risky parenting practices were associated with higher substance use. The associations were robust to adjustment for cumulative dopaminergic sensitizing genotype. No G x E interactions with dopaminergic genotype and family SES were observed.

LIMITATIONS

Sample size was relatively small for genetic analysis and polygenic risk scores were not available.

CONCLUSIONS

Exposure to cumulative psychosocial family risks from early childhood is associated with early indicators of problem behavior in adolescence.

Interactive effects of DRD2 rs6277 polymorphism, environment and sex on impulsivity in a population-representative study

Previous research has shown that dopaminergic dysregulation and early life stress interact to impact on aspects of impulse control. This study aimed to explore the potentially interactive effects of the rs6277 polymorphism of the dopamine D2 receptor gene (DRD2), stressful or supportive environment and sex on behavioural and self-reported measures of impulsivity, as well as alcohol use - a condition characterised by a deficit in impulse control. The sample consisted of the younger cohort (n = 583) of the longitudinal Estonian Children Personality, Behaviour and Health Study. The results showed that the CC homozygotes (suggested to have decreased striatal D2 receptor availability) who had experienced stressful life events (SLE) or maltreatment in the family prior to age 15 showed higher self-reported maladaptive impulsivity at age 15. The genotype-SLE interaction and further association with sex was also evident in the frequency of alcohol use at age 15. Lack of warmth in the family contributed to significantly higher levels of thoughtlessness and more frequent alcohol use in CC carriers at age 25, whereas family support was associated with lower thoughtlessness scores in CC males, which may suggest a protective effect of supportive family environment in this group. Together the findings suggest that DRD2 rs6277 polymorphism, in interaction with environmental factors experienced in childhood and youth may affect facets of impulsivity. Future work should aim to further clarify the sex and age-specific effects of stressful and supportive environment on the development of neuronal systems that are compromised in disorders characterised by deficits in impulse control.

Serotonergic sensitivity alleles moderate relations between attachment security at age three and socioemotional competence at age five

Children with higher socioemotional competence are more likely to build constructive relationships with others and experience more positive adjustment outcomes in later periods. Securely attached children are likely to develop better socioemotional competence, but genetic moderation of associations between attachment and later socioemotional competence has received less attention. Using structural equation modeling, this study analyzed data collected from 1,337 children (51% male) born from 1998 to 2000 in the Fragile Families and Child Wellbeing study. The results demonstrated that relations between attachment security at age 3 years and their social competence at age 5 years differed by two serotonin transporter variants (5-HTTLPR, STin2). Effect sizes of these interactions were larger than effect sizes of main effects and the benefit of having sensitive alleles was consistently supported. This implies that having more secure attachment in the early developmental period is advantageous especially for children with minor alleles who have greater environmental sensitivity.

A Scoping Review of Anxiety in Young Children with Autism Spectrum Disorder

Research on anxiety in children and adolescents with autism spectrum disorder (ASD) has burgeoned in the past 15 years. Most of the research has focused on school-age children, ages 6 to 18 years. Yet, recent studies suggest that anxiety can emerge in young children, under 6 years, with ASD. This scoping review synthesized the literature on anxiety in young children with ASD. Three domains of anxiety research were reviewed: (a) prevalence/severity, phenomenology, and course; (b) correlates; and (c) treatment. Four online databases were searched from the start of the database until March 2020. Keywords pertaining to anxiety, autism, and young children were entered. The search identified 44 articles for inclusion. These studies varied with respect to sample source, informants, and measures to assess anxiety. The overall prevalence of anxiety ranged from 1.6 to 62%. Sixteen of 17 studies found that young children with ASD had higher levels of anxiety compared to various control groups. A variety of DSM anxiety symptoms and disorders were present in young children with the most common symptoms being specific, social, and generalized fears. Correlates of anxiety included sensory over-responsivity, sleep disturbance, aggression/defiance, and attention deficit/hyperactivity disorder. Three cognitive behavioral treatment studies for anxiety and one developmental intervention targeting ASD symptoms showed promise in reducing anxiety. Findings indicate an early emergence of anxiety in some children with ASD. Further research on the measurement, pathophysiology, and treatment of anxiety in early childhood is critical to improving outcomes in children with ASD. LAY SUMMARY: This scoping review synthesizes the literature on anxiety in young children with autism spectrum disorder (ASD). Results indicate that children with ASD have higher levels of anxiety than children without ASD. Potential factors that could be contributing to anxiety include sensory, sleep, and behavioral problems. Preliminary studies show that anxiety can improve with cognitive behavioral treatment. These findings suggest that research on anxiety in young children with ASD should be prioritized to improve mental health outcomes.

When mummy and daddy get under your skin: A new look at how parenting affects children's DNA methylation, stress reactivity, and disruptive behavior

Child maltreatment is a global phenomenon that affects the lives of millions of children. Worldwide, as many as one in three to six children encounter physical, sexual, or emotional abuse from their caregivers. Children who experience abuse often show alterations in stress reactivity. Although this alteration may reflect a physiological survival response, it can nevertheless be harmful in the long run-increasing children's disruptive behavior and jeopardizing their development in multiple domains. But can we undo this process in at-risk children? Based on several lines of pioneering research, we hypothesize that we indeed can. Specifically, we hypothesize that highly dysfunctional parenting leads to an epigenetic pattern in children's glucocorticoid genes that contributes to stress dysregulation and disruptive behavior. However, we also hypothesize that it is possible to "flip the methylation switch" by improving parenting with known-effective parenting interventions in at-risk families. We predict that improved parenting will change methylation in genes in the glucocorticoid pathway, leading to improved stress reactivity and decreased disruptive behavior in children. Future research testing this theory may transform developmental and intervention science, demonstrating how parents can get under their children's skins-and how this mechanism can be reversed.

The nature and nurture of social development: The role of 5-HTTLPR and gene-parenting interactions

Social skills are traditionally viewed as acquired through social environments including parenting. However, biopsychosocial models highlight the importance of genetic influences and gene-environment interactions (G×Es) in child development. Extant G×E investigations often fail to account for developmental changes in the phenotype or rigorously assess the social environment using observational measures. The present study prospectively assessed 110 children (44.5% female) and their parents to explore biologically plausible independent and interactive associations of the serotonin transporter-linked polymorphic region (5-HTTLPR) and observed positive and negative parenting in prediction of (a) initial levels of social skills at school entry (age 6 years) and (b) developmental changes in social skills across the early school years (ages 6-9 years). Overall, the SS (vs. SL/LL) 5-HTTLPR genotype inversely predicted social skills across all domains, although parenting behavior moderated these associations wherein putative G×E effects differed by developmental timing and social skills domain. Positive parenting positively predicted concurrent (age 6) overall social skills for children with SL/LL genotypes, but not the SS genotype. However, for the SS group only, age 6 positive parenting positively predicted prospective growth in social responsibility, although negative parenting positively predicted growth in social cooperation. Findings suggest that 5-HTTLPR may signal differential sensitivities to parenting styles and patterns of social development, which may help to inform targeted intervention approaches to enhance person-environment fit. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Parenting, Effortful Control, and Adolescents' Externalizing Problem Behavior: Moderation by Dopaminergic Genes

Research shows that genetics and effortful control play an important role in the link between parenting and problem behavior. However, little is known about how these factors act simultaneously. This article used a moderated mediation model to examine whether effortful control mediated the link between parenting and externalizing problem behavior, and whether dopaminergic genes (i.e., polygenic index score including DAT1, DRD2, DRD4, COMT) moderated this link. Two three-wave studies were conducted on community samples (adolescents: Study 1: N = 457; M_age = 15.74; Study 2: N = 221; M_age = 12.84). There was no mediation by effortful control, but a moderation by dopaminergic reactivity was observed. Despite inconsistent evidence, this article indicates that the development of externalizing problem behavior is subject to genetic characteristics and parenting.

Evaluating Neighborhood, Social, and Genetic Influences on Precursors of Alcohol Use Risk Behavior in African American Adolescents

Background: Using a socioecological framework, we examined neighborhood and social stressors in concert with genetic risk for alcohol dependence in relation to externalizing behaviors, important precursors to alcohol-related problems. Methods: We used data from African American adolescents and their caregivers in the Gene, Environment, and Neighborhood Initiative, a subsample of the Mobile Youth and Poverty Study. Participants for the current analyses included 112 adolescents who reported ever having at least one full drink of alcohol. Empirical Bayes scores were used to estimate neighborhood-level violence and transitions. Multivariate models tested main effects and then interactions of family stressors, discrimination, and genetic risk with the neighborhood variables. Results: In the main effects model, adolescent externalizing behaviors were positively associated with greater family stressors, more racial discrimination experiences, and genetic liability, while neighborhood variables were nonsignificant. We found three significant interactions. Specifically, the joint effects of neighborhood violence and transitions and between these neighborhood variables and family stressors were significantly associated with externalizing behaviors. Conclusions: Our findings suggest genetic liability and complex interactions between neighborhood context and social stressors are important contributors that should be considered in the development of early prevention programs for adolescents who live in economically disadvantaged areas.

Emotional insecurity as a mediator of the moderating role of dopamine genes in the association between interparental conflict and youth externalizing problems

This study tested whether the association between interparental conflict and adolescent externalizing symptoms was moderated by a polygenic composite indexing low dopamine activity (i.e., 7-repeat allele of DRD4; Val alleles of COMT; 10-repeat variants of DAT1) in a sample of seventh-grade adolescents (Mean age = 13.0 years) and their parents. Using a longitudinal, autoregressive design, observational assessments of interparental conflict at Wave 1 predicted increases in a multi-informant measurement of youth externalizing symptoms 2 years later at Wave 3 only for children who were high on the hypodopaminergic composite. Moderation was expressed in a “for better” or “for worse” form hypothesized by differential susceptibility theory. Thus, children high on the dopaminergic composite experienced more externalizing problems than their peers when faced with more destructive conflicts but also fewer externalizing problems when exposed to more constructive interparental conflicts. Mediated moderation findings indicated that adolescent reports of their emotional insecurity in the interparental relationship partially explained the greater genetic susceptibility experienced by these children. More specifically, the dopamine composite moderated the association between Wave 1 interparental conflict and emotional insecurity 1 year later at Wave 2 in the same “for better” or “for worse” pattern as externalizing symptoms. Adolescent insecurity at Wave 2, in turn, predicted their greater externalizing symptoms 1 year later at Wave 3. Post hoc analyses further revealed that the 7-repeat allele of the dopamine receptor D4 (DRD4) gene was the primary source of plasticity in the polygenic composite. Results are discussed as to how they advance process-oriented Gene x Environment models of emotion regulation.

The interplay of polygenic plasticity and adrenocortical activity as sources of variability in pathways among family adversity, youth emotional reactivity, and psychological problems

This study examined the interplay between a polygenic composite and cortisol activity as moderators of the mediational pathway among family adversity, youth negative emotional reactivity to family conflict, and their psychological problems. The longitudinal design contained three annual measurement occasions with 279 adolescents (Mean age = 13.0 years) and their parents. Latent difference score analyses indicated that observational ratings of adversity in interparental and parent-child interactions at Wave 1 predicted increases in a multimethod, multi-informant assessment of youth negative emotional reactivity to family conflict from Waves 1 to 2. Changes in youth negative emotional reactivity, in turn, predicted increases in a multi-informant (i.e., parents, adolescent, and teacher) assessment of psychological problems from Waves 1 to 3. Consistent with differential susceptibility theory, the association between family adversity and negative emotional reactivity was stronger for adolescents who carried more sensitivity alleles in a polygenic composite consisting of 5-HTTLPR, DRD4 VNTR, and BDNF polymorphisms. Analyses of adolescent cortisol in the period surrounding a family disagreement task at Wave 1 revealed that overall cortisol output, rather than cortisol reactivity, served as an endophenotype of the polygenic composite. Overall cortisol output was specifically associated with polygenic plasticity and moderated the association between family adversity and youth negative emotional reactivity in the same for better or for worse manner as the genetic composite. Finally, moderator-mediated-moderation analyses indicated that the moderating role of the polygenic plasticity composite was mediated by the moderating role of adolescent cortisol output in the association between family adversity and their emotional reactivity.

Effects of the interaction between genetic factors and maltreatment on child and adolescent psychiatric disorders

We evaluated the effects of the interaction between child maltreatment (CM) and single nucleotide polymorphisms (SNPs) on development of mental disorders (MD) and psychopathology. We genotyped 720 individuals from a Brazilian community school-based prospective study, focusing on SNPs in 21 genes known to be associated with mental disorders. CM was assessed via a multi-informant-measure, which was previously validated. To test G × CM, we used linear or logistic models depending on variable evaluated (MD or dimensional psychopathology). After Bonferroni multiple comparison correction, we did not find any statistically significant association of G × CM with either MD or psychopathology.

Serotonin and aggressive behaviour in children and adolescents: a systematic review

OBJECTIVE

The role of serotonin (5-HT) in human aggression has been the subject of a large number of studies, mostly with adults. Meta-analyses indicate a small but significant inverse relationship between central nervous 5-HT availability and aggression, but genetically informed studies suggest two pathways: one to reactive aggression and the other to proactive aggression.

METHOD

We conducted a systemic review on central nervous 5-HT function in children and adolescents, with attention to the function of aggression.

RESULTS

In total, 675 articles were screened for relevance, with 45 reviewed. These included blood assays (e.g. plasma, 5-HIAA; platelet 5-HTR_2A ), epigenetic studies, retrospective PET studies and 5-HT challenge paradigms (e.g. tryptophan depletion). Overall, findings were mixed, with support both for negative and for positive associations of central nervous 5-HT function with aggression in children and adolescents.

CONCLUSION

We propose factors that may be blurring the picture, including problems in the conceptualization and measurement of aggression in young people, the lack of prospective designs and the bias towards clinical samples of boys. Research needs to account for variance in the both motivation for and implementation of aggression, and look to the behavioural economics literature to consider the roles of reward, vengeance and self-control more clearly.

Violence exposure in an urban city: A GxE interaction with aggressive and impulsive behaviors

BACKGROUND

Previous research has demonstrated a reciprocal relationship between community violence exposure and disruptive behavior problems among youth. No study to date, however, has explored the potential interaction between violence exposure in early adolescence and genetics.

METHODS

We explore the gene x environment interaction's impact on teacher-rated aggressive and impulsive behaviors. Violence exposure during the middle school years was assessed using self-report. Genetic data collection occurred in emerging adulthood. A polygenic score was created using findings from a conduct disorder symptomatology genome-wide association study.

RESULTS

Three longitudinal classes of teacher reported aggressive and impulsive behavior were identified. We found a significant relationship between violence exposure and class membership. There was a significant GxE interaction, such that those with below average levels of the polygenic score and who were exposed to violence were more likely to be in the moderately high aggressive and impulsive class as compared to the no to low class.

CONCLUSIONS

These findings highlight the influence of genetic risk together with violence exposure on adolescent problem behavior. Although youth may have little control over the environments in which they live, interventions can and should focus on helping all youth.

Aggressive Incidents in Residential Youth Care

It is assumed that group climate can have an effect on aggressive behavior in adolescents living in residential facilities, but it is largely unknown whether there are climate differences between the various types of residential institutions, and whether group climate differently affects aggression incidents among adolescents placed in institutions that differ in levels of security (and openness). In current research, the differences in perception of group climate between open, semi-secure, and secure residential youth care facilities were examined as well as the association between group climate and aggression. In total, 159 adolescents (96 males, 63 females) completed the Prison Group Climate Instrument (PGCI), and (aggressive) incidents were recorded during a period of 3 months. Perception of group climate-including support from staff, group atmosphere among adolescents, possibilities for growth, and repression-did not differ between the various types of residential care, except for possibilities for growth. Adolescents in open and semi-secure institutions experienced more possibilities for growth than their peers in secure institutions. A more positive perception of group climate in open institutions proved to be related to less aggressive incidents at the living group. For semi-secure and secure institutions, no relation between group climate and aggression was found. Also, the longer adolescents stayed in residential youth care, the more aggressive incidents occurred.

Genetic influences on antisocial behavior: recent advances and future directions

Understanding the etiology of antisocial behavior (i.e. violence, criminality, rule-breaking), is essential to the development of more effective prevention and intervention strategies. We provide a summary of the genetic correlates of antisocial behavior, drawing upon findings from behavioral, molecular, and statistical genetics. Across methodologies, our review highlights the centrality of environmental moderators of genetic effects, and how behavioral heterogeneity in antisocial behavior is an important consideration for genetic studies. We also review novel analytic techniques and neurogenetic approaches that can be used to examine how genetic variation predicts antisocial behavior. Finally, to illustrate how findings may converge across approaches, we describe pathways from genetic variability in oxytocin signaling to subtypes of antisocial behavior.

Genetic and Psychosocial Predictors of Aggression: Variable Selection and Model Building With Component-Wise Gradient Boosting

Rationale: Given datasets with a large or diverse set of predictors of aggression, machine learning (ML) provides efficient tools for identifying the most salient variables and building a parsimonious statistical model. ML techniques permit efficient exploration of data, have not been widely used in aggression research, and may have utility for those seeking prediction of aggressive behavior.

Objectives: The present study examined predictors of aggression and constructed an optimized model using ML techniques. Predictors were derived from a dataset that included demographic, psychometric and genetic predictors, specifically FK506 binding protein 5 (FKBP5) polymorphisms, which have been shown to alter response to threatening stimuli, but have not been tested as predictors of aggressive behavior in adults.

Methods: The data analysis approach utilized component-wise gradient boosting and model reduction via backward elimination to: (a) select variables from an initial set of 20 to build a model of trait aggression; and then (b) reduce that model to maximize parsimony and generalizability.

Results: From a dataset of N = 47 participants, component-wise gradient boosting selected 8 of 20 possible predictors to model Buss-Perry Aggression Questionnaire (BPAQ) total score, with R² = 0.66. This model was simplified using backward elimination, retaining six predictors: smoking status, psychopathy (interpersonal manipulation and callous affect), childhood trauma (physical abuse and neglect), and the FKBP5_13 gene (rs1360780). The six-factor model approximated the initial eight-factor model at 99.4% of R².

Conclusions: Using an inductive data science approach, the gradient boosting model identified predictors consistent with previous experimental work in aggression; specifically psychopathy and trauma exposure. Additionally, allelic variants in FKBP5 were identified for the first time, but the relatively small sample size limits generality of results and calls for replication. This approach provides utility for the prediction of aggression behavior, particularly in the context of large multivariate datasets.

Relationships between parents' academic backgrounds and incomes and building students' healthy eating habits

BACKGROUND

Building healthy eating habit is essential for all people. School and family are the prime institutions to instill this habit during early age. This study is aimed at understanding the impact of family such as parents' educations and incomes on building students' healthy eating habits.

METHODS

A survey on building students' eating habits was conducted among primary school students of grade 4 (11 years) and 5 (12 years) from Kulim district, Malaysia. Data from 318 respondents were analysed. Descriptive statistics were used to find the present scenario of their knowledge, attitude and practices towards their eating habits while one-way ANOVA and independent sample t-test were used to find the differences between their practices based on students' gender, parents' educations and incomes.

RESULTS

The study finds that the students have a good knowledge of types of healthy food but yet their preferences are towards the unhealthy food. Though the students' gender and parents' educations are not found significantly related to students' knowledge, attitude and practices towards healthy eating habits, parents' incomes have significant influence on promoting the healthy eating habit.

DISCUSSION

Findings of this study can be useful to guide parents in healthy food choices and suggest them to be models to their children in building healthy eating habits.

COMT Val158 Met moderates the link between rank and aggression in a non-human primate

The COMT Val¹⁵⁸ Met polymorphism is one of the most widely studied genetic polymorphisms in humans implicated in aggression and the moderation of stressful life event effects. We screened a wild primate population for polymorphisms at the COMT Val¹⁵⁸ Met site and phenotyped them for aggression to test whether the human polymorphism exists and is associated with variation in aggressive behavior. Subjects were all adults from 4 study groups (37 males, 40 females) of Assamese macaques (Macaca assamensis) in their natural habitat (Phu Khieo Wildlife Sanctuary, Thailand). We collected focal animal behavioral data (27 males, 36 females, 5964 focal hours) and fecal samples for non-invasive DNA analysis. We identified the human COMT Val¹⁵⁸ Met polymorphism (14 Met/Met, 41 Val/Met and 22 Val/Val). Preliminary results suggest that COMT genotype and dominance rank interact to influence aggression rates. Aggression rates increased with rank in Val/Val, but decreased in Met/Met and Val/Met individuals, with no significant main effect of COMT genotype on aggression. Further support for the interaction effect comes from time series analyses revealing that when changing from lower to higher rank position Val/Val individuals decreased, whereas Met/Met individuals increased their aggression rate. Contradicting the interpretation of earlier studies, we show that the widely studied Val¹⁵⁸ Met polymorphism in COMT is not unique to humans and yields similar behavioral phenotypes in a non-human primate. This study represents an important step towards understanding individual variation in aggression in a wild primate population and may inform human behavioral geneticists about the evolutionary roots of inter-individual variation in aggression.

Sometimes It's Good to be Short: The Serotonin Transporter Gene, Positive Parenting, and Adolescent Depression

In threatening environments, the short (S) allele of 5-HTTLPR is proposed to augment risk for depression. However, it is unknown whether 5-HTTLPR variation increases risk for depression in environments of deprivation, lacking positive or nurturant features. Two independent longitudinal studies (n = 681 and 176, respectively) examined whether 5-HTTLPR moderated associations between low levels of positive parenting at 11-13 years and subsequent depression at 17-19 years. In both studies only LL homozygous adolescents were at greater risk for depression with decreasing levels of positive parenting. Thus, while the S allele has previously been identified as a susceptible genotype, these findings suggest that the L allele may also confer sensitivity to depression in the face of specific environmental challenges.

An exploration of common dopaminergic variants and behavior problems in siblings at high risk for autism spectrum disorder

Younger siblings of children with ASD often exhibit elevated internalizing and externalizing problems. We investigated common dopaminergic variants (DRD4 and DRD2) in relation to behavior problems at 36 months. Genotypes linked to less efficient dopaminergic functioning were associated with higher internalizing problems in high-risk siblings.

Prenatal programming of postnatal plasticity for externalizing behavior: Testing an integrated developmental model of genetic and temperamental sensitivity to the environment

Although both gene- and temperament-environment interactions contribute to the development of youth externalizing problems, it is unclear how these factors jointly affect environmental sensitivity over time. In a 7-year longitudinal study of 232 children (aged 5-10) with and without ADHD, we employed moderated mediation to test a developmentally sensitive mechanistic model of genetic and temperamental sensitivity to prenatal and postnatal environmental factors. Birth weight, a global measure of the prenatal environment, moderated predictions of child negative emotionality from a composite of dopaminergic polymorphisms (i.e., DRD4 and DAT1), such that birth weight inversely predicted negative emotionality only for children with genetic plasticity. Negative emotionality, in turn, predicted externalizing behavior 4-5 years later, beyond genetic and postnatal parenting effects. Finally, birth weight moderated the indirect effect of dopaminergic genotypes on externalizing problems through negative emotionality, partially supporting a prenatal programming model. We discuss theoretical and empirical implications for models of environmental sensitivity.

Disruptive Behavior Disorders in Children 0 to 6 Years Old

Disruptive behavior disorders (DBDs), specifically oppositional defiant disorder and conduct disorder, are common, serious, and treatable conditions among preschoolers. DBDs are marked by frequent aggression, deceitfulness, and defiance, and often persist through the lifespan. Exposure to harsh or inconsistent parenting, as frequently seen with parental depression and stress, increases DBD risk. Candidate genes that may increase DBD risk in the presence of childhood adversity have also been identified, but more research is needed. Neurophysiologic and structural correlates with DBD also exist. Parent management training programs, focusing on increasing parenting competence and confidence, are the gold standard treatment of preschool DBDs.

Comparación de la respuesta inhibitoria en niños y adolescentes diagnosticados con TOC y TDAH

Antecedentes: Los trastornos de comportamiento tienen asociados una serie de factores que van más allá de los síntomas, entre los cuales está el funcionamiento cognoscitivo. En TOC y TDAH se han encontrado dificultades en el funcionamiento ejecutivo, siendo la inhibición de respuestas una de las fallas más consistentes en diferentes estudios. Objetivos: Comparar la respuesta inhibitoria de niños y adolescentes diagnosticados con TDAH, TOC con población sana. Método: Se analizaron 31 pacientes con TDAH, 31 con TOC y 66 controles a partir del Test Stroop de colores y palabras segunda edición (Golden, 1999). Resultados: Se encuentran diferencias de los grupos clínicos con los controles; TOC vs controles (p = 0.03419), TDAH vs controles (p= 0.00244), pero no entre los grupos clínico TOC vs TDAH (p= 0.2793). Al comparar rango de edad se encuentran diferencias específicas entre los mismos grupos para los participantes entre 13-16 años (TDAH: p=0.005 y TOC: 0.018) y controles. Conclusiones: Los resultados son coherentes con lo reportado en la literatura, respecto a la alteración del control inhibitorio de personas con TOC y TDAH. Se deben realizar análisis más amplios en otros dominios cognitivos para poder tener un perfil más claro de los aspectos comunes y diferenciables de personas con trastornos del neurodesarrollo y manifestaciones anormales de comportamiento.

Does the Incredible Years reduce child externalizing problems through improved parenting? The role of child negative affectivity and serotonin transporter linked polymorphic region (5-HTTLPR) genotype

In a randomized controlled trial, the Observational Randomized Controlled Trial of Childhood Differential Susceptibility (ORCHIDS study), we tested whether observed parental affect and observed and reported parenting behavior are mechanisms of change underlying the effects of the behavioral parent training program the Incredible Years (IY). Furthermore, we tested whether some children are more susceptible to these change mechanisms because of their temperamental negative affectivity and/or serotonin transporter linked polymorphic region (5-HTTLPR) genotype. Participants were 387 Dutch children between 4 and 8 years of age (M age = 6.31, SD = 1.33; 55.3% boys) and their parents. Results showed that although IY was successful in improving parenting behavior and increasing parental positive affect, these effects did not explain the significant decreases in child externalizing problems. We therefore found no evidence for changes in parenting behavior or parental affect being the putative mechanisms of IY effectiveness. Furthermore, intervention effects on child externalizing behavior were not moderated by child negative affectivity or 5-HTTLPR genotype. However, child 5-HTTLPR genotype did moderate intervention effects on negative parenting behavior. This suggests that in research on behavioral parent training programs, "what works for which parents" might also be an important question.

Adolescent externalizing behaviour, psychological control, and peer rejection: Transactional links and dopaminergic moderation

This study investigated (1) reciprocal links among parental psychological control, peer rejection, and adolescent externalizing (aggressive and rule-breaking behaviour), and (2) the moderating effect of an adolescent genetic factor (biologically informed polygenic score for dopamine signalling). Three-year longitudinal data from 1,116 adolescents (51% boys; M age = 13.79) and their parents included psychological measures (adolescent-reported psychological control, peer-reported rejection, and parent-reported aggressive and rule-breaking behaviour). Cross-lagged analyses showed bidirectional effects between psychological control and both aggressive and rule-breaking behaviour and a unidirectional effect of peer rejection on both forms of problem behaviour over time. Multigroup structural equation modelling revealed genetic moderation only for rule-breaking behaviour: for adolescents with intermediate levels of dopamine signalling significant environmental effects were present, whereas adolescent effects of rule-breaking behaviour on psychological control were significant for adolescents with both intermediate and high profiles and effects on peer rejection only for adolescents with high dopamine profiles. Statement of contribution What is already known on this subject? Parental psychological control is related to adolescent externalizing problems. Experiencing peer rejection reinforces aggressive and rule-breaking behaviour. Single-gene studies show that dopaminergic genes influence externalizing problems directly or in interaction with the environment. What does this study add? Parental psychological control and adolescent aggressive and rule-breaking behaviour exacerbate one another longitudinally. Longitudinal associations between peer rejection and both subtypes of externalizing behaviour are unidirectional. With a polygenic approach, dopaminergic moderation is present for rule-breaking behaviour only.

Preschoolers' genetic, physiological, and behavioral sensitivity factors moderate links between parenting stress and child internalizing, externalizing, and sleep problems

This study examined three potential moderators of the relations between maternal parenting stress and preschoolers' adjustment problems: a genetic polymorphism-the short allele of the serotonin transporter (5-HTTLPR, ss/sl allele) gene, a physiological indicator-children's baseline respiratory sinus arrhythmia (RSA), and a behavioral indicator-mothers' reports of children's negative emotionality. A total of 108 mothers (M_age  = 30.68 years, SD_age  = 6.06) reported on their parenting stress as well as their preschoolers' (M_age  = 3.50 years, SD_age  = 0.51, 61% boys) negative emotionality and internalizing, externalizing, and sleep problems. Results indicated that the genetic sensitivity variable functioned according to a differential susceptibility model; however, the results involving physiological and behavioral sensitivity factors were most consistent with a diathesis-stress framework. Implications for prevention and intervention efforts to counter the effects of parenting stress are discussed.

Trajectories of adolescent conduct problems in relation to cortical thickness development: a longitudinal MRI study

Multiple cross-sectional imaging studies have identified structural abnormalities in prefrontal, temporal and limbic regions related to conduct problems (CPs). However, the relationship between development of such neurobiological deficits and developmental pathways of CPs has remained unclear. The current study investigated distinct trajectories of CP and related trajectories of cortical thickness within a community-based sample of adolescents (n=239), age range 12-19, to address this gap. Three trajectory classes were revealed using latent class growth analyses (LCGAs), comprising a 'desisting' CP group, an 'intermediate' CP group and a 'stable low' CP group. Structural magnetic resonance imaging (MRI) scans were collected with a subgroup of 171 adolescents at three waves throughout adolescence (ages 12, 16 and 19). Generalized estimating equation (GEE) analysis-comparing longitudinal changes in cortical thickness and subcortical volume between CP groups for several regions of interest (ROIs)-showed that these CP groups had differential trajectories of cortical thickness in the dorsolateral prefrontal cortex (dl-PFC), and the anterior cingulate cortex (ACC), and volume of the hippocampus. Adolescents in the desisting CP group showed an attenuation of the typical pattern of cortical thinning as present in the intermediate and stable low CP groups, in addition to an exaggeration of the typical pattern of hippocampal volume increase. These findings suggest that a deviant cortical thickness trajectory was related to a desisting CP pathway across adolescence. Such deviant neurodevelopmental growth trajectories may act as an underlying mechanism for developmental CP pathways, and possibly distinguish desisting antisocial adolescents.