Gene-environment interaction in psychological traits and disorders

The moderating role of early-life parental adverse and positive factors in the genetic and environmental contributions to objectively assessed sleep duration in middle childhood

Early-life positive and adverse parental factors, such as positive parent personality and parental stress, affect the environmental context in which children develop and may influence individual differences in children's sleep health. This study examined the moderating role of early-life parental factors in the heritability (i.e., the extent to which individual differences are due to genetic influences) of objectively assessed childhood sleep duration. A total of 351 families from the Arizona Twin Project were studied. Primary caregivers (95% mothers) reported on multiple dimensions of stress and facets of their own personality when the twins were 12 months old. Seven years later (Mage = 8.43 years, SD = 0.68), families completed a home visit, and twins (51% female; 57% White, 29% Hispanic; 30% monozygotic, 39% same-sex dizygotic, 31% other-sex dizygotic) wore actigraph watches to assess their sleep, with caregivers completing similar assessments on their personality attributes and stress. Early-life positive parent personality moderated the heritability of sleep duration (Δ-2LL [-2 log likelihood] = 2.54, Δdf = 2, p = .28), such that as positive parent personality increased, the heritability of duration decreased. Early-life parental stress also moderated the genetic contribution to sleep duration (Δ-2LL = 2.02, Δdf = 2, p = .36), such that as stress increased, the heritability of duration increased. Concurrent positive parent personality and parental stress composites showed similar patterns of findings. Results highlight the likely contribution of parent positive traits and adverse experiences to the etiology of children's sleep health, with genetic influences on children's sleep more prominent in "riskier" environments. Understanding how genetics and environments work together to influence the etiology of sleep may inform prevention programs.

Do Children Cause the Cognitive Stimulation they Receive? Modelling the Direction of Causality

We tested the directionality of associations between children's early-life cognitive development and the cognitive stimulation that they received from their parents. Our sample included up to 15,314 children from the Twins Early Development Study (TEDS), who were born between 1994 and 1996 in England and Wales and assessed at ages 3 and 4 years on cognitive development and cognitive stimulation, including singing rhymes, reading books, and playing games. Using genetically informative cross-lagged models, we found consistent, bidirectional effects from cognitive development at age 3 to cognitive stimulation at age 4, and from cognitive stimulation at age 3 to cognitive development at age 4. These cross-lagged longitudinal effects were largely explained by underlying common genetic and shared environmental factors, rather than reflecting causal mechanisms. Our findings emphasize the active role that children play in constructing their own learning experiences.

Refining the scope of genetic influences on alcohol misuse through environmental stratification and gene-environment interaction

BACKGROUND

Gene-environment interaction (G × E) is likely an important influence shaping individual differences in alcohol misuse (AM), yet it has not been extensively studied in molecular genetic research. In this study, we use a series of genome-wide gene-environment interaction (GWEIS) and in silico annotation methods with the aim of improving gene identification and biological understanding of AM.

METHODS

We carried out GWEIS for four AM phenotypes in the large UK Biobank sample (N = 360,314), with trauma exposure and socioeconomic status (SES) as moderators of the genetic effects. Exploratory analyses compared stratified genome-wide association (GWAS) and GWEIS modeling approaches. We applied functional annotation, gene- and gene-set enrichment, and polygenic score analyses to interpret the GWEIS results.

RESULTS

GWEIS models showed few genetic variants with significant interaction effects across gene-environment pairs. Enrichment analyses identified moderation by SES of the genes NOXA1, DLGAP1, and UBE2L3 on drinking quantity and the gene IFIT1B on drinking frequency. Except for DLGAP1, these genes have not previously been linked to AM. The most robust results (GWEIS interaction p = 4.59e-09) were seen for SES moderating the effects of variants linked to immune-related genes on a pattern of drinking with versus without meals.

CONCLUSIONS

Our results highlight several genes and a potential mechanism of immune system functioning behind the moderating effect of SES on the genetic influences on AM. Although GWEIS seems to be a preferred approach over stratified GWAS, modeling G × E effects at the molecular level remains a challenge even in large samples. Understanding these effects will require substantial effort and more in-depth phenotypic measurement.

A Bayesian approach for exploring person × environment interaction within the environmental sensitivity meta-framework

BACKGROUND

For investigating the individual-environment interplay and individual differences in response to environmental exposures as captured by models of environmental sensitivity including Diathesis-stress, Differential Susceptibility, and Vantage Sensitivity, over the last few years, a series of statistical guidelines have been proposed. However, available solutions suffer of computational problems especially relevant when sample size is not sufficiently large, a common condition in observational and clinical studies.

METHOD

In the current contribution, we propose a Bayesian solution for estimating interaction parameters via Monte Carlo Markov Chains (MCMC), adapting Widaman et al. (Psychological Methods, 17, 2012, 615) Nonlinear Least Squares (NLS) approach.

RESULTS

Findings from an applied exemplification and a simulation study showed that with relatively big samples both MCMC and NLS estimates converged on the same results. Conversely, MCMC clearly outperformed NLS, resolving estimation problems and providing more accurate estimates, particularly with small samples and greater residual variance.

CONCLUSIONS

As the body of research exploring the interplay between individual and environmental variables grows, enabling predictions regarding the form of interaction and the extent of effects, the Bayesian approach could emerge as a feasible and readily applicable solution to numerous computational challenges inherent in existing frequentist methods. This approach holds promise for enhancing the trustworthiness of research outcomes, thereby impacting clinical and applied understanding.

Genetic and Environmental Influences on Sexual Orientation: Moderation by Childhood Gender Nonconformity and Early-Life Adversity

Existing evidence indicates genetic and non-genetic influences on sexual orientation; however, the possibility of gene-environment interplay has not been previously formally tested despite theories indicating this. Using a Finnish twin cohort, this study investigated whether childhood gender nonconformity and early-life adversities independently moderated individual differences in sexual orientation and childhood gender nonconformity, the relationship between them, and the etiological bases of the proposed moderation effects. Sexual orientation, childhood gender nonconformity, and early-life adversities were assessed using standard questionnaires. Structural equation twin model fitting was carried out using OpenMx. Childhood gender nonconformity was significantly associated with reduced phenotypic variance in sexual orientation (β =  - 0.14, 95% CI - 0.27, - 0.01). A breakdown of the underlying influences of this moderation effect showed that this was mostly due to moderation of individual-specific environmental influences which significantly decreased as childhood gender nonconformity increased (βE =  - 0.38; 95% CI - 0.52, - 0.001) while additive genetic influences were not significantly moderated (βA = 0.05; 95% CI - 0.30, 0.27). We also observed that the relationship between sexual orientation and childhood gender nonconformity was stronger at higher levels of childhood gender nonconformity (β = 0.10, 95% CI 0.05, 0.14); however, significance of the underlying genetic and environmental influences on this relationship could not be established in this sample. The findings indicate that beyond a correlation of their genetic and individual-specific environmental influences, childhood gender nonconformity is further significantly associated with reduced individual-specific influences on sexual orientation.

Gene-environment interplays between family chaos and emotional problems among Nigerian adolescents: A twin study

Gene-environment correlations and interactions for the relationship between emotional problems (EP) and family environment in adolescents in low- to middle-income countries (LMIC) have been rarely investigated. In total, 3207 adolescent twins aged 12-18 (Mean = 14.6 ± 1.73) years attending public schools in Lagos State in Nigeria completed measures of EP and Family Chaos (FC). Model-fitting analyses suggested that genetic and non-shared environmental influences on EP were 21% and 71%, respectively, and the corresponding estimates were 23% and 71% for FC. Shared environmental influences were not significant (8% and 6% respectively). Phenotypic correlation between EP and FC was .30 (95% CI = .27-.34), which was significantly influenced by genetic (A - 49%, 95% CI: 0.01-0.97) and non-shared environmental factors (E - 32%, 95% CI: 0.10-0.54). Shared environmental influences were not significant (C - 19%, 95% CI: -0.13 to 0.50). Moderation effects were significant whereby as FC increased, A on EP decreased (βA = -0.07, 95% CI: -0.12 to -0.02) while E increased (βE = 0.06, 95% CI: 0.03-0.09). Our findings indicate that genetic and non-shared environmental risk factors may mediate the relationship between EP and FC, and that as FC increases, protective genetic influences on EP may be attenuated, whereas environmental influences may become stronger in adolescents in LMIC.

Assessing the genetic contribution of cumulative behavioral factors associated with longitudinal type 2 diabetes risk highlights adiposity and the brain-metabolic axis

While genetic factors, behavior, and environmental exposures form a complex web of interrelated associations in type 2 diabetes (T2D), their interaction is poorly understood. Here, using data from ~500K participants of the UK Biobank, we identify the genetic determinants of a "polyexposure risk score" (PXS) a new risk factor that consists of an accumulation of 25 associated individual-level behaviors and environmental risk factors that predict longitudinal T2D incidence. PXS-T2D had a non-zero heritability (h2 = 0.18) extensive shared genetic architecture with established clinical and biological determinants of T2D, most prominently with body mass index (genetic correlation [rg] = 0.57) and Homeostatic Model Assessment for Insulin Resistance (rg = 0.51). Genetic loci associated with PXS-T2D were enriched for expression in the brain. Biobank scale data with genetic information illuminates how complex and cumulative exposures and behaviors as a whole impact T2D risk but whose biology have been elusive in genome-wide studies of T2D.

Statistical methods for gene-environment interaction analysis

Most human complex phenotypes result from multiple genetic and environmental factors and their interactions. Understanding the mechanisms by which genetic and environmental factors interact offers valuable insights into the genetic architecture of complex traits and holds great potential for advancing precision medicine. The emergence of large population biobanks has led to the development of numerous statistical methods aiming at identifying gene-environment interactions (G × E). In this review, we present state-of-the-art statistical methodologies for G × E analysis. We will survey a spectrum of approaches for single-variant G × E mapping, followed by various techniques for polygenic G × E analysis. We conclude this review with a discussion on the future directions and challenges in G × E research.

Genotype-environment interplay in associations between maternal drinking and offspring emotional and behavioral problems

BACKGROUND

While maternal at-risk drinking is associated with children's emotional and behavioral problems, there is a paucity of research that properly accounts for genetic confounding and gene-environment interplay. Therefore, it remains uncertain what mechanisms underlie these associations. We assess the moderation of associations between maternal at-risk drinking and childhood emotional and behavioral problems by common genetic variants linked to environmental sensitivity (genotype-by-environment [G × E] interaction) while accounting for shared genetic risk between mothers and offspring (GE correlation).

METHODS

We use data from 109 727 children born to 90 873 mothers enrolled in the Norwegian Mother, Father, and Child Cohort Study. Women self-reported alcohol consumption and reported emotional and behavioral problems when children were 1.5/3/5 years old. We included child polygenic scores (PGSs) for traits linked to environmental sensitivity as moderators.

RESULTS

Associations between maternal drinking and child emotional (β1 = 0.04 [95% confidence interval (CI) 0.03-0.05]) and behavioral (β1 = 0.07 [0.06-0.08]) outcomes attenuated after controlling for measured confounders and were almost zero when we accounted for unmeasured confounding (emotional: β1 = 0.01 [0.00-0.02]; behavioral: β1 = 0.01 [0.00-0.02]). We observed no moderation of these adjusted exposure effects by any of the PGS.

CONCLUSIONS

The lack of strong evidence for G × E interaction may indicate that the mechanism is not implicated in this kind of intergenerational association. It may also reflect insufficient power or the relatively benign nature of the exposure in this sample.

Targeting Homocysteine and Hydrogen Sulfide Balance as Future Therapeutics in Cancer Treatment

A high level of homocysteine (Hcy) is associated with oxidative/ER stress, apoptosis, and impairment of angiogenesis, whereas hydrogen sulfide (H2S) has been found to reverse this condition. Recent studies have shown that cancer cells need to produce a high level of endogenous H2S to maintain cell proliferation, growth, viability, and migration. However, any novel mechanism that targets this balance of Hcy and H2S production has yet to be discovered or exploited. Cells require homocysteine metabolism via the methionine cycle for nucleotide synthesis, methylation, and reductive metabolism, and this pathway supports the high proliferative rate of cancer cells. Although the methionine cycle favors cancer cells for their survival and growth, this metabolism produces a massive amount of toxic Hcy that somehow cancer cells handle very well. Recently, research showed specific pathways important for balancing the antioxidative defense through H2S production in cancer cells. This review discusses the relationship between Hcy metabolism and the antiapoptotic, antioxidative, anti-inflammatory, and angiogenic effects of H2S in different cancer types. It also summarizes the historical understanding of targeting antioxidative defense systems, angiogenesis, and other protective mechanisms of cancer cells and the role of H2S production in the genesis, progression, and metastasis of cancer. This review defines a nexus of diet and precision medicine in targeting the delicate antioxidative system of cancer and explores possible future therapeutics that could exploit the Hcy and H2S balance.

Gene-by-Environment Interaction Effects of Social Adversity on Externalizing Behavior in ABCD Youth

This study tested whether multiple domains of social adversity, including neighborhood opportunity/deprivation and life stress, moderate genetic (A), common environmental (C), and unique environmental (E) influences on externalizing behaviors in 760 same-sex twin pairs (332 monozygotic; 428 dizygotic) ages 10-11 from the ABCD Study. Proportion of C influences on externalizing behavior increased at higher neighborhood adversity (lower overall opportunity). A decreased and C and E increased at lower levels of educational opportunity. A increased at lower health-environment and social-economic opportunity levels. For life stress, A decreased and E increased with number of experienced events. Results for educational opportunity and stressful life experiences suggest a bioecological gene-environment interaction pattern such that environmental influences predominate at higher levels of adversity, whereas limited access to healthcare, housing, and employment stability may potentiate genetic liability for externalizing behavior via a diathesis-stress mechanism. More detailed operationalization of social adversity in gene-environment interaction studies is needed.

Genetic Risk, Neighborhood Characteristics, and Behavioral Difficulties Among African American Adolescents Living in Very Low-Income Neighborhoods

Behavioral difficulties among African American youth are disproportionately detrimental to their future well-being compared to when demonstrated by White American youth. The majority of gene-environment studies of behavior have been conducted with European ancestry samples, limiting our knowledge of these processes among African Americans. This study examined the influence of positive and negative neighborhood conditions, in the context of genetic risk, on behavioral difficulties among low-income African American adolescents. Data were from the Genes, Environment, and Neighborhood Initiative study of African American youth in high-poverty neighborhoods, n = 524, M age = 15.89, SD = 1.42. DNA samples were collected using the Oragene Discovery 500 series, and polygenic risk scores for behavioral difficulties computed. Neighborhood informal social control, social cohesion, physical disorder, and social disorder were assessed. Adolescent alcohol use, hyperactivity/inattention and conduct problems were examined as outcomes. After controlling for polygenic risk, lower levels of neighborhood social disorder and higher levels of social cohesion were associated with fewer youth-reported hyperactivity/inattention and conduct problems. Less social disorder also was associated with fewer parent-reported behavioral difficulties. Neighborhood characteristics did not moderate associations between genetic risk and the outcomes. Higher levels of positive and lower levels of negative neighborhood characteristics can be associated with lower levels of behavioral difficulties among African American youth living in poverty, even after taking into account genetic risk.

How to estimate heritability: a guide for genetic epidemiologists

Traditionally, heritability has been estimated using family-based methods such as twin studies. Advancements in molecular genomics have facilitated the development of methods that use large samples of (unrelated or related) genotyped individuals. Here, we provide an overview of common methods applied in genetic epidemiology to estimate heritability, i.e. the proportion of phenotypic variation explained by genetic variation. We provide a guide to key genetic concepts required to understand heritability estimation methods from family-based designs (twin and family studies), genomic designs based on unrelated individuals [linkage disequilibrium score regression, genomic relatedness restricted maximum-likelihood (GREML) estimation] and family-based genomic designs (sibling regression, GREML-kinship, trio-genome-wide complex trait analysis, maternal-genome-wide complex trait analysis, relatedness disequilibrium regression). We describe how heritability is estimated for each method and the assumptions underlying its estimation, and discuss the implications when these assumptions are not met. We further discuss the benefits and limitations of estimating heritability within samples of unrelated individuals compared with samples of related individuals. Overall, this article is intended to help the reader determine the circumstances when each method would be appropriate and why.

A gene-environment cascade theoretical framework of developmental psychopathology

Previous theories have emphasized genetic effects "inside the skin" via endophenotypes within the broader developmental psychopathology theory. Expanding on the mechanisms of gene-environment correlation, we propose a new integrative framework emphasizing how genetic effects "outside the skin" (Reiss & Leve, 2007) accumulate due to individual variation in social information processing in negative environments and sociocultural contexts as part of developmental cascades to psychopathology. In this gene-environment cascade theoretical framework, genetic predisposition for psychopathology, as well as stable traits and behaviors, can lead to negative environments via gene-environment correlations that can be exacerbated or buffered by an individual's social information processing. Moreover, these "environments" range from dyadic social relationships to broader sociocultural contexts. Over time, these processes exacerbate one another as part of developmental cascades, resulting in accumulating risk for psychopathology. By focusing on gene-environment correlations and integrating disparate social-emotional, cognitive, and sociocultural research domains, this framework delineates key processes by which early genetic predisposition can contribute to developmentally distinct and accumulating risk for psychopathology over the life course. Implications for intervention and methodological advances that facilitate testing models are presented. This new framework moves the field further away from genetic determinism by informing targets of early psychosocial prevention. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Theories of psychopathology: Potential to promote clinical science, empowerment, and justice

This invited commentary evaluates eight target articles that offer ambitious theoretical frameworks intended to advance psychopathology research. We discuss their consideration of the perspectives and priorities of treatment-seekers, including respect for and promotion of individuals' agency and self-determination; their positioning of individuals within dynamic social systems and their consideration of interventions beyond the individual level; their assumptions and proposals about the relationship between psychological and biological concepts and phenomena, relative to the reductionism that has been dominant but unsuccessful in the psychopathology literature in recent decades; and their implications for clinical care and for individual and community health. Despite some overlapping features, the articles cover very different ground and offer different challenges to the status quo, which has seen strikingly slow progress for decades. None of the proposed theories is comprehensive, but each has unique appeals; each has limitations, and each warrants consideration and development. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

DNA methylation as a mediator in the association between prenatal maternal stress and child mental health outcomes: Current state of knowledge

BACKGROUND

Prenatal maternal stress is increasingly recognized as a risk factor for offspring mental health challenges. DNA methylation may be a mechanism, but few studies directly tested mediation. These few integrative studies are reviewed along with studies from three research areas: prenatal maternal stress and child mental health, prenatal maternal stress and child DNA methylation, and child mental health and DNA methylation.

METHODS

We conducted a narrative review of articles in each research area and the few published integrative studies to evaluate the state of knowledge.

RESULTS

Prenatal maternal stress was related to greater offspring internalizing and externalizing symptoms and to greater offspring peripheral DNA methylation of the NR3C1 gene. Youth mental health problems were also related to NR3C1 hypermethylation while epigenome-wide studies identified genes involved in nervous system development. Integrative studies focused on infant outcomes and did not detect significant mediation by DNA methylation though methodological considerations may partially explain these null results.

LIMITATIONS

Operationalization of prenatal maternal stress and child mental health varied greatly. The few published integrative studies did not report conclusive evidence of mediation by DNA methylation.

CONCLUSIONS

DNA methylation likely mediates the association between prenatal maternal stress and child mental health. This conclusion still needs to be tested in a larger number of integrative studies. Key empirical and statistical considerations for future research are discussed. Understanding the consequences of prenatal maternal stress and its pathways of influence will help prevention and intervention efforts and ultimately promote well-being for both mothers and children.

The Promise and Peril of Genetics

Human genetics is advancing at an unprecedented pace. Improvements in genotyping technology and rapidly falling costs have accelerated gene discovery. We can now comprehensively scan the genome, testing variation across millions of genetic markers, to identify specific variants associated with any outcome of interest. Large consortia consisting of hundreds of scientists are analyzing data from hundreds of thousands to millions of individuals. Multivariate methods now enable us to identify genes involved in underlying processes, to complement studies focused on specific disorders or traits. There has been an exponential increase in use of direct-to-consumer genetic feedback platforms. These advances are poised to have a widespread effect on medicine and society. However, with such rapid progress will come ethical, social, and legal challenges. Among those challenges is the need for increased efforts to enhance public understanding of the ways genes contribute to complex behavioral outcomes, and for increased diversity in the field of genetics to ensure that all people benefit from advances. Psychologists can play an important role in addressing the inevitable questions that will arise as genetics increasingly becomes mainstream.

The next 10 years of behavioural genomic research

Background

The explosion caused by the fusion of quantitative genetics and molecular genetics will transform behavioural genetic research in child and adolescent psychology and psychiatry.

Methods

Although the fallout has not yet settled, the goal of this paper is to predict the next 10 years of research in what could be called behavioural genomics.

Results

I focus on three research directions: the genetic architecture of psychopathology, causal modelling of gene-environment interplay, and the use of DNA as an early warning system.

Conclusion

Eventually, whole-genome sequencing will be available for all newborns, which means that behavioural genomics could potentially be applied ubiquitously in research and clinical practice.

Microbiome–Gut Dissociation in the Neonate: Autism-Related Developmental Brain Disease and the Origin of the Placebo Effect

While the importance of the intestinal microbiome has been realised for a number of years, the significance of the phrase microbiota–gut–brain axis is only just beginning to be fully appreciated. Our recent work has focused on the microbiome as if it were a single entity, modifying the expression of the genetic inheritance of the individual by the generation of interkingdom signalling molecules, semiochemicals, such as dopamine. In our view, the purpose of the microbiome is to convey information about the microbial environment of the mother so as to calibrate the immune system of the new-born, giving it the ability to distinguish harmful pathogens from the harmless antigens of pollen, for example, or to help distinguish self from non-self. In turn, this requires the partition of nutrition between the adult and its microbiome to ensure that both entities remain viable until the process of reproduction. Accordingly, the failure of a degraded microbiome to interact with the developing gut of the neonate leads to failure of this partition in the adult: to low faecal energy excretion, excessive fat storage, and concomitant problems with the immune system. Similarly, a weakened gut–brain axis distorts interoceptive input to the brain, increasing the risk of psychiatric diseases such as autism. These effects account for David Barker’s 1990 suggestion of “the fetal and infant origins of adult disease”, including schizophrenia, and David Strachan’s 1989 observation of childhood immune system diseases, such as hay fever and asthma. The industrialisation of modern life is increasing the intensity and scale of these physical and psychiatric diseases and it seems likely that subclinical heavy metal poisoning of the microbiome contributes to these problems. Finally, the recent observation of Harald Brüssow, that reported intestinal bacterial composition does not adequately reflect the patterns of disease, would be accounted for if microbial eukaryotes were the key determinant of microbiome effectiveness. In this view, the relative success of “probiotic” bacteria is due to their temporary immune system activation of the gut–brain axis, in turn suggesting a potential mechanism for the placebo effect.

Relationship between adverse childhood experiences and symptom severity in adult men with Tourette Syndrome

Childhood adversity is associated with the development or expression of many neuropsychiatric disorders, including those with strong genetic underpinnings. Despite reported associations between perceived stress and tic severity, the relationship between potentially traumatic events in childhood and Tourette Syndrome (TS), a highly heritable neuropsychiatric disorder, is unknown. This study aimed to assess whether exposure to eight categories of adverse childhood experiences (ACEs) is associated with TS severity and impairment, and whether TS genetic risk modifies this association. Online survey data were collected from 351 adult males with TS who previously participated in genetic studies. Participants completed the ACE questionnaire and a lifetime version of the Yale Global Tic Severity Scale (YGTSS). Demographic and relevant health data were assessed; polygenic risk scores (PRS) measuring aggregated TS genetic risk were derived using genome-wide association data. Univariable and multivariable linear regressions examined the relationships between childhood adversity and retrospectively recalled worst-ever tic severity and impairment, adjusting for covariates. Potential gene-by-environment (GxE) interactions between ACE and PRS were estimated. After covariate adjustment, there was a significant graded dose-response relationship between ACE Scores and increases in lifetime worst-ever tic severity and impairment. There was some evidence that TS genetic risk moderated the relationship between ACE Score and tic impairment, but not tic severity, particularly for individuals with higher TS polygenic risk. We provide evidence that childhood adversity is associated with higher lifetime TS severity and impairment, although future longitudinal studies with genetically-sensitive designs are needed to determine whether these relationships are causal and/or directional.

The effect of environment on cross-sensitization between methylphenidate and amphetamine in female rats

Methylphenidate (MPD) and amphetamine (AMP) are both psychostimulants that are often used to treat behavioral disorders. More recently, it has also been increasingly used illicitly for recreation as well as to improve intellectual performance. Many factors such as age, gender, genetic background, and environment govern the development of behavioral sensitization to MPD and cross-sensitization with other drugs, which are experimental behavioral markers indicating potential of substance dependence and abuse. This study examines the effects of the environment and age when MPD was exposed in adulthood alone as well as in adolescence into adulthood on cross-sensitization with AMP in female SD rats by randomizing animals to either receive the drug in a home cage or a test cage during adolescence, adulthood, or both. In a 34 day experiment, 16 groups of animals starting in adolescence were treated with saline on experimental day one (ED1), followed by a 6 day (ED2-ED7) treatment with either saline, 0.6 mg/kg AMP, 0.6, 2.5, or 10.0 mg/kg MPD. Experimental groups were then subject to a 3-day washout period (ED8-ED10) and then a retreatment with the respective drug on ED11 in adolescence (P-38 to P-49). Experiments continued in the same animal groups now in adulthood (P-60) with a saline treatment (ED1), followed by the same sequence of treatments in adolescence (ED2-ED11;P-61 to P-69). A rechallenge with the same AMP or MPD dose was performed on ED11 (P-70) followed by a single exposure to 0.6 mg/kg AMP on ED12 (P-71) to assess for cross sensitization between MPD and AMP. Animals treated with MPD in both adolescence and adulthood and in the last experimental day of AMP (ED12) showed higher intensity of cross-sensitivity between MPD and AMP as compared to animals treated with MPD only in adulthood. AMP and MPD treatment in adolescence and into adulthood in the home or test cage resulted in significantly higher responses to the drug as compared to those treated only in adulthood. Overall, we conclude that environmental alteration and adolescent exposure to MPD appeared to increase the risk of cross-sensitization to AMP in female SD rats i.e, using MPD in adolescence may increase the probability of becoming dependent on drugs of abuse. This further indicates that age, sex, and environment all influence the response to MPD and AMP, and further work is needed to elucidate the risks associated with MPD and AMP use.

Early adversity as the prototype gene × environment interaction in mental disorders?

Childhood adversity (CA) as a significant stressor has consistently been associated with the development of mental disorders. The interaction between CA and genetic variants has been proposed to play a substantial role in disease etiology. In this review, we focus on the gene by environment (GxE) paradigm, its background and interpretation and stress the necessity of its implementation in psychiatric research. Further, we discuss the findings supporting GxCA interactions, ranging from candidate gene studies to polygenic and genome-wide approaches, their strengths and limitations. To illustrate potential underlying epigenetic mechanisms by which GxE effects are translated, we focus on results from FKBP5 × CA studies and discuss how molecular evidence can supplement previous GxE findings. In conclusion, while GxE studies constitute a valuable line of investigation, more harmonized GxE studies in large, deep-phenotyped, longitudinal cohorts, and across different developmental stages are necessary to further substantiate and understand reported GxE findings.

Parenting in the Context of the Child: Genetic and Social Processes

The focus on the role of parenting in child development has a long-standing history. When measures of parenting precede changes in child development, researchers typically infer a causal role of parenting practices and attitudes on child development. However, this research is usually conducted with parents raising their own biological offspring. Such research designs cannot account for the effects of genes that are common to parents and children, nor for genetically influenced traits in children that influence how they are parented and how parenting affects them. The aim of this monograph is to provide a clearer view of parenting by synthesizing findings from the Early Growth and Development Study (EGDS). EGDS is a longitudinal study of adopted children, their birth parents, and their rearing parents studied across infancy and childhood. Families (N = 561) were recruited in the United States through adoption agencies between 2000 and 2010. Data collection began when adoptees were 9 months old (males = 57.2%; White 54.5%, Black 13.2%, Hispanic/Latinx 13.4%, Multiracial 17.8%, other 1.1%). The median child age at adoption placement was 2 days (M = 5.58, SD = 11.32). Adoptive parents were predominantly in their 30s, White, and coming from upper-middle- or upper-class backgrounds with high educational attainment (a mode at 4-year college or graduate degree). Most adoptive parents were heterosexual couples, and were married at the beginning of the project. The birth parent sample was more racially and ethnically diverse, but the majority (70%) were White. At the beginning of the study, most birth mothers and fathers were in their 20s, with a mode of educational attainment at high school degree, and few of them were married. We have been following these family members over time, assessing their genetic influences, prenatal environment, rearing environment, and child development. Controlling for effects of genes common to parents and children, we confirmed some previously reported associations between parenting, parent psychopathology, and marital adjustment in relation to child problematic and prosocial behavior. We also observed effects of children's heritable characteristics, characteristics thought to be transmitted from parent to child by genetic means, on their parents and how those effects contributed to subsequent child development. For example, we found that genetically influenced child impulsivity and social withdrawal both elicited harsh parenting, whereas a genetically influenced sunny disposition elicited parental warmth. We found numerous instances of children's genetically influenced characteristics that enhanced positive parental influences on child development or that protected them from harsh parenting. Integrating our findings, we propose a new, genetically informed process model of parenting. We posit that parents implicitly or explicitly detect genetically influenced liabilities and assets in their children. We also suggest future research into factors such as marital adjustment, that favor parents responding with appropriate protection or enhancement. Our findings illustrate a productive use of genetic information in prevention research: helping parents respond effectively to a profile of child strengths and challenges rather than using genetic information simply to identify some children unresponsive to current preventive interventions.

Predicting Alcohol Use From Genome-Wide Polygenic Scores, Environmental Factors, and Their Interactions in Young Adulthood

OBJECTIVE

Alcohol use during emerging adulthood is associated with adverse life outcomes, but its risk factors are not well known. Here, we predicted alcohol use in 3153 young adults aged 22 years from a) genome-wide polygenic scores (GPS) based on genome-wide association studies for the target phenotypes number of drinks per week and Alcohol Use Disorders Identification Test scores, b) 30 environmental factors, and c) their interactions (i.e., G × E effects).

METHODS

Data were collected from 1994 to 2018 as a part of the UK Twins Early Development Study.

RESULTS

GPS accounted for up to 1.9% of the variance in alcohol use (i.e., Alcohol Use Disorders Identification Test score), whereas the 30 measures of environmental factors together accounted for 21.1%. The 30 GPS by environment interactions did not explain any additional variance, and none of the interaction terms exceeded the significance threshold after correcting for multiple testing.

CONCLUSIONS

GPS and some environmental factors significantly predicted alcohol use in young adulthood, but we observed no GPS by environment interactions in our study.

Breastfeeding moderates the relationship between fat mass and obesity-associated gene rs9939609 and body mass index among adolescents

OBJECTIVE

Breastfeeding, which is important for early growth, is a possible moderator of genetic influence, such as the effect of the fat mass and obesity-associated gene (FTO) on body mass index (BMI). The aim of this study was to assess the moderating effect of breastfeeding duration on the relationship between FTO rs9939609 and BMI in a Caucasian sample.

METHODS

Adolescents born in 1997 and in 1999, who were living in the Swedish county Västmanland in 2012, were invited to participate in the Survey of Adolescent Life in Västmanland. The adolescents and their parents completed self-reported questionnaires in 2012, 2015, and 2018. Genotyping of rs9939609 T > A polymorphism was conducted from saliva DNA samples. Interaction effects of parental reported breastfeeding duration in months, including regions of significance, on the relationship between rs9939609 and BMI plus overweight were assessed.

RESULTS

Considering physical activity levels, parental reported breastfeeding duration was a moderator of the relationship between rs9939609 and BMI for the younger (regions of significance = <1.6 and >28.1 months) and older adolescents (region of significance = >19.9 months), but not for the young adults. Plots of the association between breastfeeding duration and BMI showed higher BMI for AA with short breastfeeding, but lower BMI with longer breastfeeding than AT and TT. Longer breastfeeding lowered the odds for overweight among the younger adolescents, especially among AA individuals.

CONCLUSION

Rs9939609 AA individuals were more susceptible than AT and TT individuals to both short and long breastfeeding durations, which is consistent with the differential susceptibility hypothesis. FTO rs9939609 AA might be a plasticity variant with differential susceptibility to environmental influences. Breastfeeding duration may be one of many factors that affect the relationship between rs9939609 and BMI.

Long‐lasting Housing Environment Manipulation and Acute Loss of Environmental Enrichment Impact BALB/c Mice Behavior in Multiple Functional Domains

Understanding environmental influences on individuals' behaviour is challenging. Here we have investigated the housing impact of 9 weeks of enriched environment (EE) and social isolation (SI) and the impact of abrupt deprivation of EE (enrichment removal: ER) on BALB/c mice. Compared with the widely used C57BL/6 strain in research, BALB/c synthesises serotonin less efficiently due to a genetic variation and thus may potentially represent human populations at higher risk of stress‐related disorders. We assessed the effects of EE and SI by conducting a behavioural test battery and the effects of acute ER by monitoring homecage activities and social behaviour. We found that EE and SI impact BALB/c's physiological states and behavioural performances from lower to higher cognitive processes: increased body weight, increased rectal temperature, altered performance in motor and sensory tasks, the activity level in a novel environment and altered performance in tests of anxiety‐like behaviour, stress‐coping strategies and learning and memory. Furthermore, acute ER triggered stress/frustration‐like behaviour in BALB/c, with increased aggression, increased social distancing and disrupted daily/nightly activities. Our results demonstrate that long‐lasting housing manipulation such as EE and SI, impact behaviour via multilayered processes over a wide range of functional domains, and unforeseen change to a negative environment, ER, is a major stressor that causes behavioural and psychological consequences through environment–gene interactions, a model of direct relevance to human health.

Increased depressive and anxiety symptoms in non-heterosexual individuals: Moderation by childhood factors using a twin design

BACKGROUND

Evidence indicates that minority stress does not sufficiently explain mental health disparities in non-heterosexual compared to heterosexual individuals. We investigated alternative mechanisms whereby childhood factors (childhood gender nonconformity, early-life adversities and parent-child interactions) moderate the relationships between sexual orientation and depressive and anxiety symptoms.

METHODS

The sample comprised twin pairs from the Finnish Genetics of Sexuality and Aggression cohort (n = 3166 individuals, mean age = 37.5 ± 2.93 years). Twin analyses using structural equation modelling was performed in OpenMx. Specifically, we tested whether childhood factors differentially moderated the underlying genetic and environmental influences on the relationships between sexual orientation, and depressive and anxiety symptoms.

RESULTS

The associations between non-heterosexuality, and depressive and anxiety symptoms (r = 0.09, 0.10 respectively) were significantly influenced by both genetic and environmental factors. The genetic influences explaining the relationships of sexual orientation with depressive and anxiety symptoms were maximal at high levels of childhood gender nonconformity (β_A = 0.09 and 0.11 respectively) whereas the individual-specific environmental influences on these relationships were maximal at lower levels of childhood gender nonconformity (β_E = -0.10).

LIMITATIONS

Childhood factors were assessed retrospectively in a cross-sectional design.

CONCLUSIONS

Childhood gender nonconformity is associated with increased genetic and decreased individual-specific environmental influences on mental health among non-heterosexual individuals. Childhood gender nonconformity may, thus, enhance genetic risk and non-genetic protective processes for depressive and anxiety symptoms among non-heterosexual individuals.

From Genome-Wide to Environment-Wide: Capturing the Environome

Genome-wide association (GWA) studies have shown that genetic influences on individual differences in affect, behavior, and cognition are driven by thousands of DNA variants, each with very small effect sizes. Here, we propose taking inspiration from GWA studies for understanding and modeling the influence of the environment on complex phenotypes. We argue that the availability of DNA microarrays in genetic research is comparable with the advent of digital technologies in psychological science that enable collecting rich, naturalistic observations in real time of the environome, akin to the genome. These data can capture many thousand environmental elements, which we speculate each influence individual differences in affect, behavior, and cognition with very small effect sizes, akin to findings from GWA studies about DNA variants. We outline how the principles and mechanisms of genetic influences on psychological traits can be applied to improve the understanding and models of the environome.

Gene-Environment Interactions in Attention-Deficit/Hyperactivity Disorder Symptom Dimensions: The Role of Unhealthy Food Habits

Background: Dietary habits were investigated as environmental risk factors for Attention-Deficit/Hyperactivity Disorder (ADHD). However, no previous studies explored the effects of dietary factors on modifying the role of genetic factors on ADHD. Methods: Based on a Swedish population-based twin study with 1518 twin pairs aged 20-47 years, we tested whether the importance of genetic and environmental effects on ADHD varied as a function of dietary habits. Self-reported dietary habits and ADHD symptoms were collected. Twin methods were used to test the degree to which high-sugar and unhealthy food intake moderated the genetic and environmental influences on ADHD symptoms. Results: In middle-aged adults, genetic influences on inattention symptoms were statistically significantly higher among individuals with higher levels of high-sugar (45%, 95%CI: 25-54%) and unhealthy food intake (51%, 95%CI: 31-60%), compared with those with lower levels of consumption of high-sugar (36%, 95%CI: 25-47%) and unhealthy foods (30%, 95%CI: 20-41%). Similar patterns were also found for the associations between hyperactivity/impulsivity and high-sugar/unhealthy food intake, even though the moderation effects were not statistically significant. Conclusion The present study suggests that genetic factors play a more prominent role in individual differences of ADHD symptoms in the presence of the high consumption of sugar and unhealthy foods. Future longitudinal studies with multiple assessments of ADHD and dietary habits are needed to replicate our findings.

Quantile-Dependent Heritability of Glucose, Insulin, Proinsulin, Insulin Resistance, and Glycated Hemoglobin

BACKGROUND

"Quantile-dependent expressivity" is a dependence of genetic effects on whether the phenotype (e.g., insulin resistance) is high or low relative to its distribution.

METHODS

Quantile-specific offspring-parent regression slopes (βOP) were estimated by quantile regression for fasting glucose concentrations in 6,453 offspring-parent pairs from the Framingham Heart Study.

RESULTS

Quantile-specific heritability (h2), estimated by 2βOP/(1 + rspouse), increased 0.0045 ± 0.0007 (p = 8.8 × 10-14) for each 1% increment in the fasting glucose distribution, that is, h2 ± SE were 0.057 ± 0.021, 0.095 ± 0.024, 0.146 ± 0.019, 0.293 ± 0.038, and 0.456 ± 0.061 at the 10th, 25th, 50th, 75th, and 90th percentiles of the fasting glucose distribution, respectively. Significant increases in quantile-specific heritability were also suggested for fasting insulin (p = 1.2 × 10-6), homeostatic model assessment of insulin resistance (HOMA-IR, p = 5.3 × 10-5), insulin/glucose ratio (p = 3.9 × 10-5), proinsulin (p = 1.4 × 10-6), proinsulin/insulin ratio (p = 2.7 × 10-5), and glucose concentrations during a glucose tolerance test (p = 0.001), and their logarithmically transformed values.

DISCUSSION/CONCLUSION

These findings suggest alternative interpretations to precision medicine and gene-environment interactions, including alternative interpretation of reported synergisms between ACE, ADRB3, PPAR-γ2, and TNF-α polymorphisms and being born small for gestational age on adult insulin resistance (fetal origin theory), and gene-adiposity (APOE, ENPP1, GCKR, IGF2BP2, IL-6, IRS-1, KIAA0280, LEPR, MFHAS1, RETN, TCF7L2), gene-exercise (INS), gene-diet (ACSL1, ELOVL6, IRS-1, PLIN, S100A9), and gene-socioeconomic interactions.

Heritability of Locomotor Stereotypies in Chilean Horses

The Chilean horse is a breed of closed registry. Stall-walking and weaving are locomotor stereotypies that affect this breed, and genetic predisposition has been suggested for both conditions. The objective of the present study was to estimate heritability of stall-walking and weaving in Chilean horses. Owners of 2,098 horses registered in the Chilean horse Stud Book, which were or had been stabled for at least 1 year, were asked to provide for identification data of the animal and presence or absence of stall-walking and/or weaving. The Chilean Horse Stud Book was accessed online, to collect information on name and registration number of the sire and dam of each horse. The prevalence of stall-walking and weaving was calculated from the sample (n = 2,098). The database to estimate the heritability (h²) included all the sample horses (n = 2,098) and their sires and dams. Additionally, all the ancestors available in the Chilean Horse Stud Book were included in the database for 297 sampled horses including those with locomotor stereotypies. The genealogical database consisted of 7,187 individuals. The prevalence of stall-walking was 2.05% and prevalence of weaving was 1.43%, being more frequent in males (P < .05) for stall-walking. Heritability of stall-walking was low (h² = 0.213 ± 0.08) and moderate for weaving (h² = 0.435 ± 0.06). Heritability and prevalence of locomotor stereotypies found in the Chilean horse suggest that they are hereditary disorders, highly influenced by environmental factors.

Childhood Antisocial Behavior: A Neurodevelopmental Problem

Early-onset disruptive, aggressive, and antisocial behavior is persistent, can become increasingly serious as children grow older, and is difficult to change. In 2007, our group proposed a theoretical model highlighting the interplay between neurobiological deficits and cognitive and emotional functioning as mediators of the link between genetic influences and early social adversity, on the one hand, and antisocial behavioral problems in childhood, on the other. In this article, we review the post-2007 evidence relevant to this model. We discuss research on genetics/epigenetics, stress/arousal regulation, and emotion and executive functioning in support of the argument that antisocial children, especially those who persist in engaging in antisocial behavior as they grow older, have a range of neuropsychological characteristics that are important in explaining individual differences in the severity and persistence of antisocial behavior. Current clinical practice tends not to acknowledge these individual neuropsychological risks factors or to target them for intervention. We argue that aggressive and disruptive behavior in childhood should be regarded as a neurodevelopmental problem and that intervening at the level of mediating neuropsychological processes represents a promising way forward in tackling these serious behavioral problems. Expected final online publication date for the Annual Review of Psychology, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Three-way interaction effects of early life stress, positive parenting and FKBP5 in the development of depressive symptoms in a general population

FKBP5 gene–environment interaction (cG × E) studies have shown diverse results, some indicating significant interaction effects between the gene and environmental stressors on depression, while others lack such results. Moreover, FKBP5 has a potential role in the diathesis stress and differential susceptibility theorem. The aim of the present study was to evaluate whether a cG × E interaction effect of FKBP5 single-nucleotide polymorphisms (SNPs) or haplotype and early life stress (ELS) on depressive symptoms among young adults was moderated by a positive parenting style (PASCQ^pos), through the frameworks of the diathesis stress and differential susceptibility theorem. Data were obtained from the Survey of Adolescent Life in Västmanland Cohort Study, including 1006 participants and their guardians. Data were collected during 2012, when the participants were 13 and 15 years old (Wave I: DNA), 2015, when participants were 16 and 18 years old (Wave II: PASCQ^pos, depressive symptomology and ELS) and 2018, when participants were 19 and 21 years old (Wave III: depressive symptomology). Significant three-way interactions were found for the FKBP5 SNPs rs1360780, rs4713916, rs7748266 and rs9394309, moderated by ELS and PASCQ^pos, on depressive symptoms among young adults. Diathesis stress patterns of interaction were observed for the FKBP5 SNPs rs1360780, rs4713916 and rs9394309, and differential susceptibility patterns of interaction were observed for the FKBP5 SNP rs7748266. Findings emphasize the possible role of FKBP5 in the development of depressive symptoms among young adults and contribute to the understanding of possible differential susceptibility effects of FKBP5.

Marital Satisfaction as a Moderator of Molecular Genetic Influences on Mental Health

The quality of one's romantic relationship is associated with mental health. Low levels of relationship quality may be a stressor that triggers a predisposition or diathesis to mental illness. Analyses were conducted to examine whether relationship quality moderated the association between polygenic risk scores (PRSs) for several mental health syndromes on phenotypic measures of those syndromes. Data were drawn from the Midlife in the United States (MIDUS) study of health and well-being. A subsample was genotyped, and PRSs were calculated. The PRS for anxiety was more strongly related to the anxiety phenotype when satisfaction was low than when satisfaction was high, providing evidence of a genetic susceptibility process between marital distress and anxiety. The expression of genetic influences on a phenotype in the presence of certain environmental stressors is complex and may depend on the specific phenotype and the methodology by which genetic influences are estimated.

The Role of Social Determinants in Mental Health and Resilience After Disasters: Implications for Public Health Policy and Practice

In this general literature review, we will explore the impacts and contribution of social determinants to mental health and resiliency following both natural and man-made disasters. Natural disasters, such as wildfires, earthquakes, tsunamis, and hurricanes, as well as man-made disasters, such as civil wars, have been known to inflict significant damage to the mental health of the victims. In this paper, we mainly explore some most studied vulnerability and protective social determinant factors such as gender, age, ethnicity, socials support and socioeconomic status for the mental health and resiliency in survivors of such disasters. Several other possible factors such as previous trauma, childhood abuse, family psychiatric history, and subsequent life stress that were explored by some studies were also discussed. We conducted a literature search in major scientific databases, using keywords such as: mental health, social determinants, disasters, wildfires, earthquakes, terrorist attacks, and resilience. We discuss the implications for public health policy and practice.

Heterogeneous frailty and the expression of linear enamel hypoplasia in a genealogical population

OBJECTIVES

Linear enamel hypoplasia (LEH) is a common skeletal marker of physiological stress (e.g., malnutrition or illness) that is studied within and across populations, without reference to familial risk. We examine LEH prevalence in a population with known genealogical relationships to determine the potential influence of genetic heritability and shared environment.

METHODS

LEH data of 239 individuals from a single population were recorded from the Ohio State University Menegaz-Bock collection dental casts. All individuals were of known age, sex, and genealogy. Narrow-sense heritability estimates were obtained for LEH presence and count data from all unworn, fully erupted teeth (excluding third molars) using SOLAR (v.8.1.1). Age, sex, and age-sex interaction were included as covariates. Models were re-run with a household effect variable.

RESULTS

LEH persists across generations in this study population with moderate, significant heritability estimates for presence in four teeth, and count in four teeth (three teeth were significant for both). When a household effect variable was added, no residual heritability remained for LEH count on any tooth. There was no significant household effect for three of the four teeth that had significant heritability estimates for LEH presence. Age was a significant covariate. Further analyses with birth year data revealed a secular trend toward less LEH.

CONCLUSIONS

This study provides evidence for familial risk of LEH (genetic and environmental) that has consequences for the broad use of this skeletal marker of stress. These results have repercussions for archaeological assemblages, or population health studies, where genetic relatives and household groups might be heavily represented.

The ABCD study: understanding the development of risk for mental and physical health outcomes

Following in the footsteps of other large "population neuroscience" studies, the Adolescent Brain Cognitive Development℠ (ABCD) study is the largest in the U.S. assessing brain development. The study is examining approximately 11,875 youth from 21 sites from age 9 to 10 for approximately ten years into young adulthood. The ABCD Study® has completed recruitment for the baseline sample generally using a multi-stage probability sample including a stratified random sample of schools. The dataset has a wealth of measured attributes of youths and their environment, including neuroimaging, cognitive, biospecimen, behavioral, youth self-report and parent self-report metrics, and environmental measures. The initial goal of the ABCD Study was to examine risk and resiliency factors associated with the development of substance use, but the project has expanded far beyond this initial set of questions and will also greatly inform our understanding of the contributions of biospecimens (e.g., pubertal hormones), neural alterations, and environmental factors to the development of both healthy behavior and brain function as well as risk for poor mental and physical outcomes. This review outlines how the ABCD Study was designed to elucidate factors associated with the development of negative mental and physical health outcomes and will provide a selective overview of results emerging from the ABCD Study. Such emerging data includes initial validation of new instruments, important new information about the prevalence and correlates of mental health challenges in middle childhood, and promising data regarding neural correlates of both healthy and disordered behavior. In addition, we will discuss the challenges and opportunities to understanding both healthy development and the emergence of risk from ABCD Study data. Finally, we will overview the future directions of this large undertaking and the ways in which it will shape our understanding of the development of risk for poor mental and physical health outcomes.

Gene-environment interaction in chronic kidney disease among people with type 2 diabetes from The Malaysian Cohort project: a case-control study

AIM

To examine the possible gene-environment interactions between 32 single nucleotide polymorphisms and environmental factors that could modify the probability of chronic kidney disease.

METHODS

A case-control study was conducted involving 600 people with type 2 diabetes (300 chronic kidney disease cases, 300 controls) who participated in The Malaysian Cohort project. Retrospective subanalysis was performed on the chronic kidney disease cases to assess chronic kidney disease progression from the recruitment phase. We genotyped 32 single nucleotide polymorphisms using mass spectrometry. The probability of chronic kidney disease and predicted rate of newly detected chronic kidney disease progression were estimated from the significant gene-environment interaction analyses.

RESULTS

Four single nucleotide polymorphisms (eNOS rs2070744, PPARGC1A rs8192678, KCNQ1 rs2237895 and KCNQ1 rs2283228) and five environmental factors (age, sex, smoking, waist circumference and HDL) were significantly associated with chronic kidney disease. Gene-environment interaction analyses revealed significant probabilities of chronic kidney disease for sex (PPARGC1A rs8192678), smoking (eNOS rs2070744, PPARGC1A rs8192678 and KCNQ1 rs2237895), waist circumference (eNOS rs2070744, PPARGC1A rs8192678, KCNQ1 rs2237895 and KCNQ1 rs2283228) and HDL (eNOS rs2070744 and PPARGC1A rs8192678). Subanalysis indicated that the rate of newly detected chronic kidney disease progression was 133 cases per 1000 person-years (95% CI: 115, 153), with a mean follow-up period of 4.78 (SD 0.73) years. There was a significant predicted rate of newly detected chronic kidney disease progression in gene-environment interactions between KCNQ1 rs2283228 and two environmental factors (sex and BMI).

CONCLUSIONS

Our findings suggest that the gene-environment interactions of eNOS rs2070744, PPARGC1A rs8192678, KCNQ1 rs2237895 and KCNQ1 rs2283228 with specific environmental factors could modify the probability for chronic kidney disease.

Analysis of stress responses in Astyanax larvae reveals heterogeneity among different populations

Stress responses are conserved physiological and behavioral outcomes as a result of facing potentially harmful stimuli, yet in pathological states, stress becomes debilitating. Stress responses vary considerably throughout the animal kingdom, but how these responses are shaped evolutionarily is unknown. The Mexican cavefish has emerged as a powerful system for examining genetic principles underlying behavioral evolution. Here, we demonstrate that cave Astyanax have reduced behavioral and physiological measures of stress when examined at larval stages. We also find increased expression of the glucocorticoid receptor, a repressible element of the neuroendocrine stress pathway. Additionally, we examine stress in three different cave populations, and find that some, but not all, show reduced stress measures. Together, these results reveal a mechanistic system by which cave-dwelling fish reduced stress, presumably to compensate for a predator poor environment.

Personality, romantic relationships, and alcohol use disorder symptoms in adolescence and young adulthood: An evaluation of personality × social context interplay

Prior research has shown that person-level characteristics (e.g., temperament, personality) correlate and interact with social-contextual factors (e.g., parent-child relationship quality, antisocial peer affiliation) to predict adolescent substance use, but less research has examined similar processes for adult substance use problems. We addressed this gap by testing for personality × romantic partner context interplay in relation to symptoms of alcohol use disorder (AUD) at ages 24 and 29. Participants were twins in the longitudinal Minnesota Twin Family Study (N = 2,769; 52% female). Results support the corresponsive principle of personality in that we found that key personality traits in late adolescence (low constraint, negative emotionality) predicted subsequent "selection" into key social contexts in early adulthood (poorer quality romantic relationships and greater romantic partner alcohol use), which subsequently reinforced those traits and associated outcomes (including correlated AUD symptoms) through late young adulthood. There were few meaningful gender differences in these associations. There was also no support for the personality × romantic partner context interaction as a significant predictor of AUD symptoms at ages 24 or 29. Taken together with prior studies, these results suggest that such interactions may be less relevant to the development of young adult AUD compared to adolescent substance use problems.

Genomic regions influencing aggressive behavior in honey bees are defined by colony allele frequencies

For social animals, the genotypes of group members affect the social environment, and thus individual behavior, often indirectly. We used genome-wide association studies (GWAS) to determine the influence of individual vs. group genotypes on aggression in honey bees. Aggression in honey bees arises from the coordinated actions of colony members, primarily nonreproductive "soldier" bees, and thus, experiences evolutionary selection at the colony level. Here, we show that individual behavior is influenced by colony environment, which in turn, is shaped by allele frequency within colonies. Using a population with a range of aggression, we sequenced individual whole genomes and looked for genotype-behavior associations within colonies in a common environment. There were no significant correlations between individual aggression and specific alleles. By contrast, we found strong correlations between colony aggression and the frequencies of specific alleles within colonies, despite a small number of colonies. Associations at the colony level were highly significant and were very similar among both soldiers and foragers, but they covaried with one another. One strongly significant association peak, containing an ortholog of the Drosophila sensory gene dpr4 on linkage group (chromosome) 7, showed strong signals of both selection and admixture during the evolution of gentleness in a honey bee population. We thus found links between colony genetics and group behavior and also, molecular evidence for group-level selection, acting at the colony level. We conclude that group genetics dominates individual genetics in determining the fatal decision of honey bees to sting.

Cumulative Influence of Inflammatory Response Genetic Variation on Long-Term Neurobehavioral Outcomes after Pediatric Traumatic Brain Injury Relative to Orthopedic Injury: An Exploratory Polygenic Risk Score

The addition of genetic factors to prognostic models of neurobehavioral recovery following pediatric traumatic brain injury (TBI) may account for unexplained heterogeneity in outcomes. The present study examined the cumulative influence of candidate genes involved in the inflammatory response on long-term neurobehavioral recovery in children with early childhood TBI relative to children with orthopedic injuries (OI). Participants were drawn from a prospective, longitudinal study evaluating outcomes of children who sustained TBI (n = 67) or OI (n = 68) between the ages of 3 and 7 years. Parents completed ratings of child executive function and behavior at an average of 6.8 years after injury. Exploratory unweighted and weighted polygenic risk scores (PRS) were constructed from single nucleotide polymorphisms (SNPs) across candidate inflammatory response genes (i.e., angiotensin converting enzyme [ACE], brain-derived neurotrophic factor [BDNF], interleukin-1 receptor antagonist [IL1RN], and 5'-ectonucleotidase [NT5E]) that showed nominal (p ≤ 0.20) associations with outcomes in the TBI group. Linear regression models tested the PRS × injury group (TBI vs. OI) interaction term and post-hoc analyses examined the effect of PRS within each injury group. Higher inflammatory response PRS were associated with more executive dysfunction and behavior problems in children with TBI but not in children with OI. The cumulative influence of inflammatory response genes as measured by PRS explained additional variance in long-term neurobehavioral outcomes, over and above well-established predictors and single candidate SNPs tested individually. The results suggest that some of the unexplained heterogeneity in long-term neurobehavioral outcomes following pediatric TBI may be attributable to a child's genetic predisposition to a greater or lesser inflammatory response to TBI.

Bound Together: How Psychoanalysis Diminishes Inter-generational DNA Trauma

The concept of intergenerational transmission of trauma plays a fundamental role in psychoanalysis. While it is known that intergenerational trauma can be transmitted through attachment relationships, a new branch of genetics (epigenetics) has emerged to study the interaction between human behavior and changes in DNA expression. Therefore, psychoanalysis, which has proven to reduce the intergenerational transmission of trauma from a behavioral perspective, can play a positive role in regulating DNA changes caused by environmental stress. The present paper focuses on recent research suggesting a direct correlation between psychological trauma and DNA modifications. In particular, DNA changes caused by psychological trauma can be transmitted from generation to generation, validating the psychoanalytic concept of intergenerational transmission of trauma. This evidence not only supports the essential role psychoanalysis has in influencing human behavior, but also suggests that it affects not only the individuals who undergo it but their offspring, as well, via the epigenetic passage of DNA.

Family functioning and psychological distress in a sample of mental health outpatients: Implications for routine examination and screening

RATIONALE, AIMS, AND OBJECTIVES

Clinical and research evidence suggests that family functioning is an important variable in shaping psychological well-being, despite being often overlooked in the prevailing approaches to mental health. The aim of the present study is to examine the associations between psychological distress and family functioning in a sample of patients accessing a public mental health service.

METHOD

CORE-OM and FACES IV questionnaires were administered to 112 patients, and all the correlations between the scales and subscales were calculated. Descriptive statistics concerning family typologies and satisfaction with family communication or relationships were also evaluated.

RESULTS

The results showed significant associations between family functioning and psychological well-being. Positive aspects of family functioning, such as balanced cohesion and flexibility, were associated with lower distress, while negative aspects such as disengagement were associated with poorer mental health. According to the Circumplex model, most of the families were described as balanced in their functioning; however, the communication and family satisfaction scores revealed that many patients had concerns about their family relationships.

CONCLUSIONS

This study confirms that family functioning is significantly associated with psychological distress, also in the absence of clear and conspicuous signs of structural imbalances within family relationships.

Systematic Review of Polygenic Risk Scores for Type 1 and Type 2 Diabetes

Recent studies have led to considerable advances in the identification of genetic variants associated with type 1 and type 2 diabetes. An approach for converting genetic data into a predictive measure of disease susceptibility is to add the risk effects of loci into a polygenic risk score. In order to summarize the recent findings, we conducted a systematic review of studies comparing the accuracy of polygenic risk scores developed during the last two decades. We selected 15 risk scores from three databases (Scopus, Web of Science and PubMed) enrolled in this systematic review. We identified three polygenic risk scores that discriminate between type 1 diabetes patients and healthy people, one that discriminate between type 1 and type 2 diabetes, two that discriminate between type 1 and monogenic diabetes and nine polygenic risk scores that discriminate between type 2 diabetes patients and healthy people. Prediction accuracy of polygenic risk scores was assessed by comparing the area under the curve. The actual benefits, potential obstacles and possible solutions for the implementation of polygenic risk scores in clinical practice were also discussed. Develop strategies to establish the clinical validity of polygenic risk scores by creating a framework for the interpretation of findings and their translation into actual evidence, are the way to demonstrate their utility in medical practice.

Mothers' distress exposure and children's withdrawn behavior - A moderating role for the Interferon Gamma gene (IFNG)

The dysregulation of the inflammatory response, including pro-inflammatory molecules, produces neuropsychiatric symptoms and depression-like behavior, including withdrawal from the physical and social environment. Genetic variants that enhance immune reactivity may thus increase inflammatory and withdrawn reactions to stress. Here we investigated a functional polymorphism of Interferon Gamma gene (IFNG +874 T > A, rs2430561) as moderator of the relationship between mothers' distress exposure and children's withdrawn behavior at preschool age. Participants were 198 Portuguese preschool children (mean age = 57.98 months). Exposure to mother's distress was assessed using the Brief Symptom Inventory, and withdrawn behavior with the Caregiver Teacher Report Form. All children provided saliva samples for genotyping. Contrary to expecations based on prior work, the rs2430561 AA genotype-not the T variant-interacted with (high levels of) mothers' distress exposure, to increase children's withdrawn behavior. No significant main effects were detected. The polymorphism in Interferon Gamma gene showed specific environmental stressor-dependent effects on withdrawn behavior during childhood, ones which are interpreted in light of the "behavioral immune system" hypothesis, and which proved inconsistent with diathesis-stress thinking.