Parental criticism and externalizing behavior problems in adolescents: the role of environment and genotype-environment correlation

Disentangling genetic and environmental influences on early language development: The interplay of genetic propensity for negative emotionality and surgency, and parenting behavior effects on early language skills in an adoption study

Parenting and children's temperament are important influences on language development. However, temperament may reflect prior parenting, and parenting effects may reflect genes common to parents and children. In 561 U.S. adoptees (57% male) and their birth and rearing parents (70% and 92% White, 13% and 4% African American, and 7% and 2% Latinx, respectively), this study demonstrated how genetic propensity for temperament affects language development, and how this relates to parenting. Genetic propensity for negative emotionality inversely predicted language at 27 months (β = -.15) and evoked greater maternal warmth (β = .12), whereas propensity for surgency positively predicted language at 4.5 years (β = .20), especially when warmth was low. Parental warmth (β = .15) and sensitivity (β = .19) further contributed to language development, controlling for common gene effects.

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.

Polygenic scores: prediction versus explanation

During the past decade, polygenic scores have become a fast-growing area of research in the behavioural sciences. The ability to directly assess people's genetic propensities has transformed research by making it possible to add genetic predictors of traits to any study. The value of polygenic scores in the behavioural sciences rests on using inherited DNA differences to predict, from birth, common disorders and complex traits in unrelated individuals in the population. This predictive power of polygenic scores does not require knowing anything about the processes that lie between genes and behaviour. It also does not mandate disentangling the extent to which the prediction is due to assortative mating, genotype-environment correlation, or even population stratification. Although bottom-up explanation from genes to brain to behaviour will remain the long-term goal of the behavioural sciences, prediction is also a worthy achievement because it has immediate practical utility for identifying individuals at risk and is the necessary first step towards explanation. A high priority for research must be to increase the predictive power of polygenic scores to be able to use them as an early warning system to prevent problems.

Multiomic biological approaches to the study of child abuse and neglect

Childhood maltreatment, occurring in up to 20-30% of the population, remains far too common, and incorporates a range of active and passive factors, from abuse, to neglect, to the impacts of broader structural and systemic adversity. Despite the effects of childhood maltreatment and adversity on a wide range of adult physical and psychological negative outcomes, not all individuals respond similarly. Understanding the differential biological mechanisms contributing to risk vs. resilience in the face of developmental adversity is critical to improving preventions, treatments, and policy recommendations. This review begins by providing an overview of childhood abuse, neglect, maltreatment, threat, and toxic stress, and the effects of these forms of adversity on the developing body, brain, and behavior. It then examines examples from the current literature of genomic, epigenomic, transcriptomic, and proteomic discoveries and biomarkers that may help to understand risk and resilience in the aftermath of trauma, predictors of traumatic exposure risk, and potential targets for intervention and prevention. While the majority of genetic, epigenetic, and gene expression analyses to date have focused on targeted genes and hypotheses, large-scale consortia are now well-positioned to better understand interactions of environment and biology with much more statistical power. Ongoing and future work aimed at understanding the biology of childhood adversity and its effects will help to provide targets for intervention and prevention, as well as identify paths for how science, health care, and policy can combine efforts to protect and promote the psychological and physiological wellbeing of future generations.

Vicious cycle of emotional maltreatment and bullying perpetration/victimization among early adolescents: Depressive symptoms as a mediator

RATIONALE

Emotional maltreatment and bullying (including both bullying perpetration and bullying victimization) are two prevalent and highly related problems among children and adolescents worldwide. The adverse consequences of emotional maltreatment and bullying behoove researchers to identify their causal mechanisms.

OBJECTIVE

We examined the reciprocal relations between emotional maltreatment and bullying perpetration/victimization and whether depressive symptoms functioned as mediator of the relations, after separating within-person effects from between-person effects.

METHODS

A total of 4273 Chinese early adolescents (45.2% girls; M_age = 9.90 years, SD = 0.73) participated in a five-wave longitudinal study with 6-month intervals.

RESULTS

Results from random intercept cross-lagged panel modeling showed: (a) emotional maltreatment and bullying perpetration were bidirectionally related; (b) bullying victimization directly predicted emotional maltreatment, but not vice versa; (c) emotional maltreatment indirectly predicted bullying perpetration/victimization via depressive symptoms; and (d) bullying victimization indirectly predicted emotional maltreatment via depressive symptoms.

CONCLUSIONS

These findings provided evidence for bidirectional spillover effects in the family and peer domains, demonstrating that early adolescents may become trapped in a vicious cycle of negative relationships, directly or indirectly, via their depressive symptoms. To prevent a downward spiral, findings suggested that bullying interventions need to address family and peer relationships as well as individual psychological well-being simultaneously to be most effective.

Mapping Pathways by Which Genetic Risk Influences Adolescent Externalizing Behavior: The Interplay Between Externalizing Polygenic Risk Scores, Parental Knowledge, and Peer Substance Use

Genetic predispositions and environmental influences both play an important role in adolescent externalizing behavior; however, they are not always independent. To elucidate gene-environment interplay, we examined the interrelationships between externalizing polygenic risk scores, parental knowledge, and peer substance use in impacting adolescent externalizing behavior across two time-points in a high-risk longitudinal sample of 1,200 adolescents (764 European and 436 African ancestry; Mage = 12.99) from the Collaborative Study on the Genetics of Alcoholism. Results from multivariate path analysis indicated that externalizing polygenic scores were directly associated with adolescent externalizing behavior but also indirectly via peer substance use, in the European ancestry sample. No significant polygenic association nor indirect effects of genetic risk were observed in the African ancestry group, likely due to more limited power. Our findings underscore the importance of gene-environment interplay and suggest peer substance use may be a mechanism through which genetic risk influences adolescent externalizing behavior.

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.

Genetics of Perceived Family Interaction From 12 to 17 Years of Age

We analyzed how the effects of genetic and environmental factors on the perceptions of family interaction change from early to late adolescence. The data were collected by postal surveys on Finnish twins (N = 4808) at 12, 14 and 17 years of age and analyzed using genetic twin modeling. Additive genetic factors explained a modest share of the variation in perceived relational support (a² = 0.30 in boys and 0.18 in girls) and relational tensions (a² = 0.13 and 0.14, respectively) at 12 years of age, with the proportions becoming larger through 17 years of age (a² = 0.53 in boys and 0.49 in girls for relational support; a² = 0.35 in boys and 0.33 in girls for relational tensions). Simultaneously, the role of environment shared by co-twins decreased. These findings suggest that the associations between perceived family interaction and other factors in adulthood should be interpreted with caution, because they partly reflect genetic background, whereas in childhood, they may provide more reliable information on parental characteristics.

Revisiting the Children-of-Twins Design: Improving Existing Models for the Exploration of Intergenerational Associations

Datasets comprising twins and their children can be a useful tool for understanding the nature of intergenerational associations between parent and offspring phenotypes. In the present article we explore structural equation models previously used to analyse Children-of-Twins data, highlighting some limitations and considerations. We then present new variants of these models, showing that extending the models to include multiple offspring per parent addresses several of the limitations discussed. Accompanying the updated models, we provide power calculations and demonstrate with application to simulated data. We then apply to intergenerational analyses of height and weight, using a sub-study of the Norwegian Mother and Child Cohort (MoBa); the Intergenerational Transmission of Risk (IToR) project, wherein all kinships in the MoBa data have been identified (a children-of-twins-and-siblings study). Finally, we consider how to interpret the findings of these models and discuss future directions.

A Comparative Study of Behavior Problems among Left-Behind Children, Migrant Children and Local Children

This study aims to estimate the prevalence of behavioral problems among left-behind children, migrant children and local children in China, and to compare the risks of behavioral problems among the three types of children. Data on 4479 children aged 6–16 used in this study were from a survey conducted in China in 2017. The school-age version of the Children Behavior Checklist was used to measure children’s behavioral problems. Descriptive analysis, correlation analysis, and logistic regressions were conducted. The prevalence of behavioral problems was 18.80% and 13.59% for left-behind children and migrant children, respectively, both of which were higher than that of local children. Logistic regression analysis showed that after adjustments for individual and environmental variables, the likelihood of total, internalizing and externalizing behavior problems for left-behind children and migrant children were higher than those for local children; left-behind children had a higher likelihood of internalizing problems than externalizing problems, while migrant children had a higher prevalence of externalizing problems. Left-behind children had a higher prevalence of each specific syndrome than migrant and local children. Both individual and environmental factors were associated with child behavioral problems, and family migration may contribute to the increased risks. Left-behind and migrant children were more vulnerable than local children to behavioral problems.

Shared genetic influences do not explain the association between parent-offspring relationship quality and offspring internalizing problems: results from a Children-of-Twins study

BACKGROUND

Associations between parenting and child outcomes are often interpreted as reflecting causal, social influences. However, such associations may be confounded by genes common to children and their biological parents. To the extent that these shared genes influence behaviours in both generations, a passive genetic mechanism may explain links between them. Here we aim to quantify the relative importance of passive genetic v. social mechanisms in the intergenerational association between parent-offspring relationship quality and offspring internalizing problems in adolescence.

METHODS

We used a Children-of-Twins (CoT) design with data from the parent-based Twin and Offspring Study of Sweden (TOSS) sample [909 adult twin pairs and their offspring; offspring mean age 15.75 (2.42) years], and the child-based Swedish Twin Study of CHild and Adolescent Development (TCHAD) sample [1120 adolescent twin pairs; mean age 13.67 (0.47) years]. A composite of parent-report measures (closeness, conflict, disagreements, expressions of affection) indexed parent-offspring relationship quality in TOSS, and offspring self-reported internalizing symptoms were assessed using the Child Behavior Checklist (CBCL) in both samples.

RESULTS

A social transmission mechanism explained the intergenerational association [r = 0.21 (0.16-0.25)] in our best-fitting model. A passive genetic transmission pathway was not found to be significant, indicating that parental genetic influences on parent-offspring relationship quality and offspring genetic influences on their internalizing problems were non-overlapping.

CONCLUSION

These results indicate that this intergenerational association is a product of social interactions between children and parents, within which bidirectional effects are highly plausible. Results from genetically informative studies of parenting-related effects should be used to help refine early parenting interventions aimed at reducing risk for psychopathology.

The influence of perceived parenting styles on socio-emotional development from pre-puberty into puberty

The relative impact of parenting on socio-emotional development of children has rarely been examined in a longitudinal context. This study examined the association between perceived parenting styles and socio-emotional functioning from childhood to adolescence. We hypothesized that optimal parenting associated with improvement in socio-emotional functioning from childhood into early adulthood, especially for those with more behavioral problems in childhood. Children between ages 7 and 9 years were recruited for the Singapore Cohort Study of Risk Factors for Myopia (SCORM). Nine years later, 700 out of 1052 subjects were followed up (67%). During childhood, parents completed the Child Behavior Checklist (CBCL), while young adults completed the Youth Self-Report (YSR) and Parental Bonding Instrument (PBI). Perceived optimal parental care resulted in less internalizing and externalizing problems in early adulthood in comparison to non-optimal parental care styles. Perceived optimal paternal parenting, but not maternal parenting, in interaction with childhood externalizing problems predicted externalizing symptoms in early adulthood. No significant interactions were found between perceived parenting styles and internalizing problems. In conclusion, perceived parental care associates with the quality of socio-emotional development, while optimal parenting by the father is especially important for children with more externalizing problems in childhood.

Affiliation with substance-using peers: Examining gene-environment correlations among parent monitoring, polygenic risk, and children's impulsivity

Parental monitoring can buffer the effect of deviant peers on adolescents' substance use by reducing affiliation with substance-using peers. However, children's genetic predispositions may evoke poorer monitoring, contributing to negative child outcomes. We examined evocative genotype-environment correlations underlying children's genetic predisposition for behavioral undercontrol and parental monitoring in early adolescence via children's impulsivity in middle childhood, and the influence of parental monitoring on affiliation with substance-using peers a year and a half later (n = 359). Genetic predisposition for behavioral undercontrol was captured using a polygenic risk score, and a portion of passive rGE was controlled by including parents' polygenic risk scores. Children's polygenic risk predicted poorer parental monitoring via greater children's impulsivity, indicating evocative rGE, controlling for a portion of passive rGE. Poorer parental monitoring predicted greater children's affiliation with substance-using peers a year and a half later. Results are discussed with respect to gene-environment correlations within developmental cascades.

Roles of Response Inhibition and Gene-Environment Interplay in Pathways to Adolescents' Externalizing Problems

This study used two waves of data to investigate pathways through which adolescents' response inhibition related to later externalizing problems. A polygenic risk score indexed genetic risk for poor response inhibition. Adolescents' performance on a response inhibition task mediated the relation between adolescents' polygenic risk scores and mother's inconsistent parenting (i.e., evocative rGE), even after controlling for mothers' genetic risk (i.e., passive rGE). Mothers' inconsistent parenting subsequently prospectively predicted adolescents' externalizing problems. Adolescents' response inhibition also prospectively predicted later externalizing behaviors. These findings were subgroup-specific, with greater risk for non-Hispanic Caucasian boys with substance-disordered parents. Results suggest that poor response inhibition may increase risk for adolescents' externalizing problems both directly and by evoking certain environmental conditions.

Associations between the parent-child relationship and adolescent self-worth: a genetically informed study of twin parents and their adolescent children

BACKGROUND

Low self-worth during adolescence predicts a range of emotional and behavioural problems. As such, identifying potential sources of influence on self-worth is important. Aspects of the parent-child relationship are often associated with adolescent self-worth but to date it is unclear whether such associations may be attributable to familial confounding (e.g. genetic relatedness). We set out to clarify the nature of relationships between parental expressed affection and adolescent self-worth, and parent-child closeness and adolescent self-worth.

METHODS

We used data from the Twin and Offspring Study in Sweden, a children-of-twins sample comprising 909 adult twin pairs with adolescent children. Using these data we were able to apply structural equation models with which we could examine whether associations remained after accounting for genetic transmission.

RESULTS

Results demonstrated that parent-child closeness and parental-expressed affection were both phenotypically associated with adolescent self-worth. Associations could not be attributed to genetic relatedness between parent and child.

CONCLUSIONS

Parent-child closeness and parental affection are associated with adolescent self-worth above and beyond effects attributable to genetic relatedness. Data were cross-sectional, so the direction of effects cannot be confirmed but findings support the notion that positive parent-child relationships increase adolescent self-worth.

Parent- and child-driven effects during the transition to adolescence: a longitudinal, genetic analysis of the home environment

Theoretical models of child development typically consider the home environment as a product of bidirectional effects, with parent‐ and child‐driven processes operating interdependently. However, the developmental structure of these processes during the transition from childhood to adolescence has not been well studied. In this study we used longitudinal genetic analyses of data from 6646 UK‐representative twin pairs (aged 9–16 years) to investigate stability and change in parenting and household chaos in the context of parent–child bidirectional effects. Stability in the home environment was modest, arising mainly from parent‐driven processes and family‐wide influences. In contrast, change over time was more influenced by child‐driven processes, indicated by significant age‐specific genetic influences. Interpretations of these results and their implications for researchers are discussed.

Polygenic score × intervention moderation: an application of discrete-time survival analysis to modeling the timing of first tobacco use among urban youth

The present study examines the interaction between a polygenic score and an elementary school-based universal preventive intervention trial. The polygenic score reflects the contribution of multiple genes and has been shown in prior research to be predictive of smoking cessation and tobacco use (Uhl et al., 2014). Using data from a longitudinal preventive intervention study, we examined age of first tobacco use from sixth grade to age 18. Genetic data were collected during emerging adulthood and were genotyped using the Affymetrix 6.0 microarray. The polygenic score was computed using these data. Discrete-time survival analysis was employed to test for intervention main and interaction effects with the polygenic score. We found a main effect of the intervention, with the intervention participants reporting their first cigarette smoked at an age significantly later than controls. We also found an Intervention × Polygenic Score interaction, with participants at the higher end of the polygenic score benefitting the most from the intervention in terms of delayed age of first use. These results are consistent with Belsky and colleagues' (e.g., Belsky, Bakermans-Kranenburg, & van IJzendoorn, 2007; Belsky & Pleuss, 2009, 2013; Ellis, Boyce, Belsky, Bakermans-Kranenburg, & van IJzendoorn, 2011) differential susceptibility hypothesis and the concept of "for better or worse," wherein the expression of genetic variants are optimally realized in the context of an enriched environment, such as provided by a preventive intervention.

Adolescent age moderates genetic and environmental influences on parent-adolescent positivity and negativity: Implications for genotype-environment correlation

We examined how genotype-environment correlation processes differ as a function of adolescent age. We tested whether adolescent age moderates genetic and environmental influences on positivity and negativity in mother-adolescent and father-adolescent relationships using parallel samples of twin parents from the Twin and Offspring Study in Sweden and twin/sibling adolescents from the Nonshared Environment in Adolescent Development Study. We inferred differences in the role of passive and nonpassive genotype-environment correlation based on biometric moderation findings. The findings indicated that nonpassive gene-environment correlation played a stronger role for positivity in mother- and father-adolescent relationships in families with older adolescents than in families with younger adolescents, and that passive gene-environment correlation played a stronger role for positivity in the mother-adolescent relationship in families with younger adolescents than in families with older adolescents. Implications of these findings for the timing and targeting of interventions on family relationships are discussed.

The etiology of the association between child antisocial behavior and maternal negativity varies across aggressive and non-aggressive rule-breaking forms of antisocial behavior

There is a robust association between negative parenting and child antisocial behavior problems. However, the etiology of this association remains unclear. Extant literature has reported strikingly different conclusions across studies, with some highlighting genetic mediation and others highlighting environmental mediation. One possible reason for these discrepancies across studies may be the failure to differentiate between aggressive and non-aggressive (rule-breaking) dimensions of childhood antisocial behavior, given their notably different etiologies and developmental trajectories (Burt 2012). The current study sought to examine the phenotypic and etiologic associations of maternal negativity with aggressive and rule-breaking antisocial behavior, respectively. Participants included 824 mothers and their twin children between the ages of 6 and 10. Our results highlighted clear etiologic distinctions in the associations of aggression and rule-breaking with maternal negativity. Aggression was associated with maternal negativity via both genetic and environmental factors, whereas the association between non-aggressive rule-breaking and maternal negativity was entirely environmental in origin. These findings provide additional support for the presence of meaningful distinctions between aggressive and non-aggressive forms of antisocial behavior, and highlight the complex relationship between parenting and child outcome.

Genetic Influences on Peer and Family Relationships Across Adolescent Development: Introduction to the Special Issue

Nearly all aspects of human development are influenced by genetic and environmental factors, which conjointly shape development through several gene-environment interplay mechanisms. More recently, researchers have begun to examine the influence of genetic factors on peer and family relationships across the pre-adolescent and adolescent time periods. This article introduces the special issue by providing a critical overview of behavior genetic methodology and existing research demonstrating gene-environment processes operating on the link between peer and family relationships and adolescent adjustment. The overview is followed by a summary of new research studies, which use genetically informed samples to examine how peer and family environment work together with genetic factors to influence behavioral outcomes across adolescence. The studies in this special issue provide further evidence of gene-environment interplay through innovative behavior genetic methodological approaches across international samples. Results from the quantitative models indicate environmental moderation of genetic risk for coercive adolescent-parent relationships and deviant peer affiliation. The molecular genetics studies provide support for a gene-environment interaction differential susceptibility model for dopamine regulation genes across positive and negative peer and family environments. Overall, the findings from the studies in this special issue demonstrate the importance of considering how genes and environments work in concert to shape developmental outcomes during adolescence.

Parental criticism is an environmental influence on adolescent somatic symptoms

Previous studies have suggested that parental criticism leads to more somatic symptoms in adolescent children. However, this research has not assessed the direction of causation or whether genetic and/or environmental influences explain the association between parental criticism and adolescent somatic symptoms. As such, it is impossible to understand the mechanisms that underlie this association. The current study uses the Extended Children of Twins design to examine whether parents' genes, adolescents' genes, and/or environmental factors explain the relationship between parental criticism and adolescent somatic symptoms. Participants came from 2 twin samples, including the Twin and Offspring Study in Sweden (N = 868 pairs of adult twins and each twin's adolescent child) and from the Twin Study of Child and Adolescent Development (N = 690 pairs of twin children and their parents). Findings showed that environmental influences account for the association between parental criticism and adolescent somatic symptoms. This suggests that parents' critical behaviors exert a direct environmental effect on somatic symptoms in adolescent children. Results support the use of intervention programs focused on parental criticism to help reduce adolescents' somatic symptoms.

Parental knowledge is an environmental influence on adolescent externalizing

BACKGROUND

There is evidence both that parental monitoring is an environmental influence serving to diminish adolescent externalizing problems and that this association may be driven by adolescents' characteristics via genetic and/or environmental mechanisms, such that adolescents with fewer problems tell their parents more, and therefore appear to be better monitored. Without information on how parents' and children's genes and environments influence correlated parent and child behaviors, it is impossible to clarify the mechanisms underlying this association.

METHOD

The present study used the Extended Children of Twins model to distinguish types of gene-environment correlation and direct environmental effects underlying associations between parental knowledge and adolescent (age 11-22 years) externalizing behavior with a Swedish sample of 909 twin parents and their adolescent offspring and a US-based sample of 405 White adolescent siblings and their parents.

RESULTS

Results suggest that more parental knowledge is associated with less adolescent externalizing via a direct environmental influence independent of any genetic influences. There was no evidence of a child-driven explanation of the association between parental knowledge and adolescent externalizing problems.

CONCLUSIONS

In this sample of adolescents, parental knowledge exerted an environmental influence on adolescent externalizing after accounting for genetic influences of parents and adolescents. Because the association between parenting and child development originates in the parent, treatment for adolescent externalizing must not only include parents but should also focus on altering their parental style. Thus, findings suggest that teaching parents better knowledge-related monitoring strategies is likely to help reduce externalizing problems in adolescents.

Gene-environment interplay between parent-child relationship problems and externalizing disorders in adolescence and young adulthood

BACKGROUND

Previous studies have shown that genetic risk for externalizing (EXT) disorders is greater in the context of adverse family environments during adolescence, but it is unclear whether these effects are long lasting. The current study evaluated developmental changes in gene-environment interplay in the concurrent and prospective associations between parent-child relationship problems and EXT at ages 18 and 25 years.

METHOD

The sample included 1382 twin pairs (48% male) from the Minnesota Twin Family Study, participating in assessments at ages 18 years (mean = 17.8, s.d. = 0.69 years) and 25 years (mean = 25.0, s.d. = 0.90 years). Perceptions of parent-child relationship problems were assessed using questionnaires. Structured interviews were used to assess symptoms of adult antisocial behavior and nicotine, alcohol and illicit drug dependence.

RESULTS

We detected a gene-environment interaction at age 18 years, such that the genetic influence on EXT was greater in the context of more parent-child relationship problems. This moderation effect was not present at age 25 years, nor did parent-relationship problems at age 18 years moderate genetic influence on EXT at age 25 years. Rather, common genetic influences accounted for this longitudinal association.

CONCLUSIONS

Gene-environment interaction evident in the relationship between adolescent parent-child relationship problems and EXT is both proximal and developmentally limited. Common genetic influence, rather than a gene-environment interaction, accounts for the long-term association between parent-child relationship problems at age 18 years and EXT at age 25 years. These results are consistent with a relatively pervasive importance of gene-environmental correlation in the transition from late adolescence to young adulthood.

Child-evoked maternal negativity from 9 to 27 months: Evidence of gene-environment correlation and its moderation by marital distress

Past research has documented pervasive genetic influences on emotional and behavioral disturbance across the life span and on liability to adult psychiatric disorder. Increasingly, interest is turning to mechanisms of gene-environment interplay in attempting to understand the earliest manifestations of genetic risk. We report findings from a prospective adoption study, which aimed to test the role of evocative gene-environment correlation in early development. Included in the study were 561 infants adopted at birth and studied between 9 and 27 months, along with their adoptive parents and birth mothers. Birth mother psychiatric diagnoses and symptoms scales were used as indicators of genetic influence, and multiple self-report measures were used to index adoptive mother parental negativity. We hypothesized that birth mother psychopathology would be associated with greater adoptive parent negativity and that such evocative effects would be amplified under conditions of high adoptive family adversity. The findings suggested that genetic factors associated with birth mother externalizing psychopathology may evoke negative reactions in adoptive mothers in the first year of life, but only when the adoptive family environment is characterized by marital problems. Maternal negativity mediated the effects of genetic risk on child adjustment at 27 months. The results underscore the importance of genetically influenced evocative processes in early development.

Understanding the relative contributions of direct environmental effects and passive genotype-environment correlations in the association between familial risk factors and child disruptive behavior disorders

BACKGROUND

Previous work reports an association between familial risk factors stemming from parental characteristics and offspring disruptive behavior disorders (DBDs). This association may reflect (a) the direct effects of familial environment and (b) a passive gene-environment correlation (r(GE)), wherein the parents provide both the genes and the environment. The current study examined the contributions of direct environmental influences and passive r(GE) by comparing the effects of familial risk factors on child DBDs in genetically related (biological) and non-related (adoptive) families.

METHOD

Participants were 402 adoptive and 204 biological families. Familial environment was defined as maternal and paternal maladaptive parenting and antisociality, marital conflict and divorce; offspring DBDs included attention deficit hyperactivity disorder (ADHD), conduct disorder (CD) and oppositional defiant disorder (ODD). Mixed-level regressions estimated the main effects of familial environment, adoption status and the familial environment by adoption status interaction term, which tested for the presence of passive r(GE).

RESULTS

There was a main effect of maternal and paternal maladaptive parenting and marital discord on child DBDs, indicating a direct environmental effect. There was no direct environmental effect of maternal or paternal antisociality, but maternal and paternal antisociality had stronger associations with child DBDs in biological families than adoptive families, indicating the presence of a passive r(GE).

CONCLUSIONS

Many familial risk factors affected children equally across genetically related and non-related families, providing evidence for direct environmental effects. The relationship of parental antisociality and offspring DBDs was best explained by a passive r(GE), where a general vulnerability toward externalizing psychopathology is passed down by the parents to the children.

Behavioral Genetic Approaches and Family Theory

Family theories have been founded on research that cannot discriminate genetic and environmental influences and, consequently, most theories do not have highly developed models of gene-environment interplay in families. Behavioral genetic approaches, which can identify gene-environment interplay, have typically not been driven by family theories and have lacked adequate measurement of family processes. In this article, the authors describe behavioral genetic mechanisms and methods using representative examples of research on family processes, highlighting the advantages of an integrated approach. New directions in research and theory driven by an integrated approach are discussed.

Adoptive parent hostility and children's peer behavior problems: examining the role of genetically informed child attributes on adoptive parent behavior

Socially disruptive behavior during peer interactions in early childhood is detrimental to children's social, emotional, and academic development. Few studies have investigated the developmental underpinnings of children's socially disruptive behavior using genetically sensitive research designs that allow examination of parent-on-child and child-on-parent (evocative genotype-environment correlation [rGE]) effects when examining family process and child outcome associations. Using an adoption-at-birth design, the present study controlled for passive genotype-environment correlation and directly examined evocative rGE while examining the associations between family processes and children's peer behavior. Specifically, the present study examined the evocative effect of genetic influences underlying toddler low social motivation on mother-child and father-child hostility and the subsequent influence of parent hostility on disruptive peer behavior during the preschool period. Participants were 316 linked triads of birth mothers, adoptive parents, and adopted children. Path analysis showed that birth mother low behavioral motivation predicted toddler low social motivation, which predicted both adoptive mother-child and father-child hostility, suggesting the presence of an evocative genotype-environment association. In addition, both mother-child and father-child hostility predicted children's later disruptive peer behavior. Results highlight the importance of considering genetically influenced child attributes on parental hostility that in turn links to later child social behavior. Implications for intervention programs focusing on early family processes and the precursors of disrupted child social development are discussed.

Gene-environment correlation underlying the association between parental negativity and adolescent externalizing problems

Studies of adolescent or parent-based twins suggest that gene-environment correlation (rGE) is an important mechanism underlying parent-adolescent relationships. However, information on how parents' and children's genes and environments influence correlated parent and child behaviors is needed to distinguish types of rGE. The present study used the novel Extended Children of Twins model to distinguish types of rGE underlying associations between negative parenting and adolescent (age 11-22 years) externalizing problems with a Swedish sample of 909 twin parents and their adolescent offspring and a U.S.-based sample of 405 adolescent siblings and their parents. Results suggest that evocative rGE, not passive rGE or direct environmental effects of parenting on adolescent externalizing, explains associations between maternal and paternal negativity and adolescent externalizing problems.

Biological and rearing mother influences on child ADHD symptoms: revisiting the developmental interface between nature and nurture

BACKGROUND

Families of children with attention deficit hyperactivity disorder (ADHD) report more negative family relationships than families of children without ADHD. Questions remain as to the role of genetic factors underlying associations between family relationships and children's ADHD symptoms, and the role of children's ADHD symptoms as an evocative influence on the quality of relationships experienced within such families. Utilizing the attributes of two genetically sensitive research designs, the present study examined associations between biologically related and nonbiologically related maternal ADHD symptoms, parenting practices, child impulsivity/activation, and child ADHD symptoms. The combined attributes of the study designs permit assessment of associations while controlling for passive genotype-environment correlation and directly examining evocative genotype-environment correlation (rGE); two relatively under examined confounds of past research in this area.

METHODS

A cross-sectional adoption-at-conception design (Cardiff IVF Study; C-IVF) and a longitudinal adoption-at-birth design (Early Growth and Development Study; EGDS) were used. The C-IVF sample included 160 mothers and children (age 5-8 years). The EGDS sample included 320 linked sets of adopted children (age 6 years), adoptive-, and biologically related mothers. Questionnaires were used to assess maternal ADHD symptoms, parenting practices, child impulsivity/activation, and child ADHD symptoms. A cross-rater approach was used across measures of maternal behavior (mother reports) and child ADHD symptoms (father reports).

RESULTS

Significant associations were revealed between rearing mother ADHD symptoms, hostile parenting behavior, and child ADHD symptoms in both samples. Because both samples consisted of genetically unrelated mothers and children, passive rGE was removed as a possible explanatory factor underlying these associations. Further, path analysis revealed evidence for evocative rGE processes in the longitudinal adoption-at-birth study (EGDS) from biologically related maternal ADHD symptoms to biologically unrelated maternal hostile parenting through early disrupted child behavior (impulsivity/activation), with maternal hostile parenting and disrupted child behavior associated with later child ADHD symptoms, controlling for concurrent adoptive mother ADHD symptoms.

CONCLUSIONS

Results highlight the importance of genetically influenced child ADHD-related temperamental attributes on genetically unrelated maternal hostility that in turn links to later child ADHD symptoms. Implications for intervention programs focusing on early family processes and the precursors of child ADHD symptoms are discussed.

Genes of experience: explaining the heritability of putative environmental variables through their association with behavioural and emotional traits

An increasing body of evidence shows that many ‘environmental’ measures are heritable, indicating genetic involvement in environmental exposure (or gene–environment correlation). In the present study we attempt to clarify why three such ‘environmental’ measures (maternal negativity, paternal negativity and negative life events) are consistently found to be heritable. Through multivariate genetic analysis of a sample of adolescent twins from the UK we show that the heritability of these putative environmental measures can be explained via their association with five behavioural phenotypes: oppositionality, delinquency, physical aggression, depression and anxiety. This is consistent with the notion that being genetically susceptible to certain behavioural difficulties could lead to exposure to certain life events, and this may account for the reported heritability of ‘environmental’ measures. Results are discussed in the context of possible active, evocative and passive gene–environment correlations.

Transactions between child social wariness and observed structured parenting: evidence from a prospective adoption study

This investigation examined the mutual influences between structured parenting and child social wariness during toddlerhood using a longitudinal adoption design. The sample consisted of 361 adoption-linked families, each including an adopted child, adoptive parents, and a birth mother. Heightened social wariness in children at age 18 months predicted reduced levels of observed structured parenting (i.e., less directive parenting with fewer commands and requests) in adoptive mothers at age 27 months. Adoptive fathers' lower structured parenting at age 18 months predicted subsequent elevation in child social wariness. Birth mothers' history of fear-related anxiety disorders was not associated with child social wariness. Findings highlight the role of dynamic family transactions in the development of social wariness during toddlerhood.

Psychological differences between smokers who spontaneously quit during pregnancy and those who do not: a review of observational studies and directions for future research

INTRODUCTION

Although remarkable interindividual differences among pregnant smokers' decision/ability to quit have been documented, the psychological factors that may account for these differences have received less attention and comprised the primary aim of this review.

METHODS

We searched the medical and behavioral sciences literature from 1996 to November 2011 using PubMed and PsycINFO(®). Fifty-one articles were identified based on titles or abstracts. These articles were reviewed in full and searched for quantitative observational studies of population-based or clinical samples, with the main topic of comparing smokers who quit spontaneously during pregnancy with those who did not, utilizing multivariable analyses.

RESULTS

The eight pertinent studies reviewed herein included four longitudinal studies and four cross-sectional analyses. Amidst significant variability among measures used, social support, depressive symptoms, and anxiety appeared unrelated to smoking cessation during pregnancy. Furthermore, when severity of nicotine dependence was controlled, maternal history of attention-deficit/hyperactivity disorder, depression, bipolar disorder, and schizophrenia all showed no independent relationship with smoking cessation during pregnancy, whereas maternal history of conduct disorder did. Secure attachment, prosocial personality, self-esteem, and perceived parenting competence were additional predictors of cessation during pregnancy.

CONCLUSIONS

A greater understanding of psychological factors that differentiate smokers who spontaneously quit during pregnancy from those who do not is crucial to the design of more effective prenatal smoking cessation interventions and also may elucidate causal mechanisms that underlie the well-established link between maternal smoking during pregnancy and offspring behavioral problems. Directions for future research and public health and policy implications are discussed.

Additional evidence against shared environmental contributions to attention-deficit/hyperactivity problems

A recent meta-analysis "Burt (Psychol Bull 135:608-637, 2009)" indicated that shared environmental influences (C) do not contribute to Attention-Deficit/Hyperactivity Disorder (ADHD). Unfortunately, the meta-analysis relied almost exclusively on classical twin studies. Although useful in many ways, some of the assumptions of the classical twin model (e.g., dominant genetic and shared environmental influences do not simultaneously influence the phenotype) can artifactually decrease estimates of C. There is thus a need to confirm that dominant genetic influences are not suppressing estimates of C on ADHD. The current study sought to do just this via the use of a nuclear twin family model, which allows researchers to simultaneously model and estimate dominant genetic and shared environmental influences. We examined two independent samples of child twins: 312 pairs from the Michigan State University Twin Registry and 854 pairs from the PrE School Twin Study in Sweden. Shared environmental influences were found to be statistically indistinguishable from zero and to account for less than 5 % of the variance. We conclude that the presence of dominant genetic influences does not account for the absence of C on ADHD.