Peer Victimization and Selective Attention in Adolescence: Evidence from a Monozygotic Twin Difference Design

Peer victimization impacts 13% of adolescents worldwide (Currie et al. 2012). Despite its prevalence and associated adverse outcomes, global cognitive processes that could be affected by peer victimization have not been thoroughly investigated. Using a monozygotic (MZ) twin difference design that rigorously controls for the influence of genetic and familial level confounders, we examined the relation between peer victimization exposure and selective attention processes during an affective go/no go task. Twins who experienced more severe peer victimization were biased towards detecting goal relevant stimuli during the task. Our findings suggest an environmentally salient relation between peer victimization and goal oriented selective attention. Future work should investigate how this process might serve to enhance or buffer risk of peer victimization exposure for developing later adverse outcomes.

Longitudinal Research at the Interface of Affective Neuroscience, Developmental Psychopathology, Health and Behavioral Genetics: Findings from the Wisconsin Twin Project

The Wisconsin Twin Project comprises multiple longitudinal studies that span infancy to early adulthood. We summarize recent papers that show how twin designs with deep phenotyping, including biological measures, can inform questions about phenotypic structure, etiology, comorbidity, heterogeneity, and gene-environment interplay of temperamental constructs and mental and physical health conditions of children and adolescents. The general framework for investigations begins with rich characterization of early temperament and follows with study of experiences and exposures across childhood and adolescence. Many studies incorporate neuroimaging and hormone assays.

Socioemotional dispositions of children and adolescents predict general and specific second-order factors of psychopathology in early adulthood: A 12-year prospective study

We previously hypothesized that the ubiquitous, but patterned correlations among all dimensions of psychopathology reflect a hierarchy of progressively more nonspecific causal influences, with a general factor of psychopathology-also dubbed the p factor-reflecting the most transdiagnostic causal influences. We further hypothesized that the general factor is a manifestation of individual differences in 1 or more trait-like dispositions, particularly negative emotionality, that are nonspecifically associated with risk for essentially every dimension of psychopathology. We tested the hypothesis that this and other dispositions measured in childhood/adolescence significantly predict general and specific second-order dimensions of psychopathology in early adulthood. The latent general factor of psychopathology itself was correlated over time from 10-17 to 23-31 years of age even though it was defined by different informants and different dimensions of symptoms. Using a measure of dispositions that minimizes item contamination with psychopathology symptoms, parent-rated negative emotionality in childhood and adolescence predicted the general factor of psychopathology based on self-reported symptoms in early adulthood, whereas parent-rated daring predicted the specific adult externalizing psychopathology factor after correction for multiple tests. In addition, youth-rated negative emotionality and daring predicted specific adult externalizing psychopathology. These results over a span of 12 years suggests that the general factor is relatively stable over time and that associations of dispositional traits with second-order dimensions of psychopathology are enduring, sometimes across informants. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Parent-Offspring Transmission of Internalizing and Sensory over-Responsivity Symptoms in Adolescence

Reactions to sensory experiences are an overlooked correlate of affective regulation, despite the importance of bodily states on psychological processes. Children who display sensory over-responsivity (i.e., adverse reactions to typical sensations) are at greater risk for developing affective disorders. We extended this literature to adolescents and their middle-aged parents. Participants in a birth record-based study of families of adolescent twins (N = 506 families; 1012 adolescents; 53% female) completed a subset of items from the Adult Sensory Profile. We derived adolescent self-reported internalizing disorder symptoms and parent affective diagnoses from structured diagnostic interviews. Structural equation models tested the relationship between parent sensory over-responsivity symptoms and affective diagnoses and their adolescent offspring's sensory over-responsivity and internalizing symptoms. Adolescent sensory over-responsivity symptoms were correlated with internalizing disorder symptoms. Parents with a diagnosis of anxiety or depression (mothers only) reported more frequent SOR symptoms than parents without a diagnosis. Parent depression was significantly related to adolescent sensory over-responsivity symptoms, over and above parent sensory over-responsivity symptoms (β = 0.26, p < 0.001 for mothers; β = 0.13, p = 0.004 for fathers). Father alcohol abuse/dependency also predicted offspring sensory over-responsivity symptoms. Offspring of parents with affective disorders were at additional risk for sensory dysregulation via parents' influence on offspring internalizing problems.

Co-occurrence of Sensory Overresponsivity with Obsessive-Compulsive Symptoms in Childhood and Early Adolescence

OBJECTIVE

Sensory overresponsivity (SOR) is characterized by challenges in integrating and responding to everyday sensory experiences. Obsessive-compulsive disorder (OCD) is characterized by intrusive thoughts, ritualistic behaviors, and sensory phenomena. There is some evidence that individuals with co-occurring symptoms of SOR and OCD experience more severe anxiety than those with symptoms of OCD alone, but most studies employed small numbers of participants (typically with an OCD diagnosis) assessed at a single time point. Our 2-fold objective was to replicate previous research showing an association between OCD symptoms and SOR symptoms concurrently and to extend these analyses longitudinally in a large, birth-register-based sample.

METHOD

Twins (N = 1613) and their primary caregivers participated in a multimodal, multimethod, longitudinal study. Primary caregivers completed the SOR inventory for their offspring at the age of 8 years, and twins completed the adult sensory profile at the age of 13 years. Parents completed the OCD module of the Diagnostic Interview Schedule for Children-IV when twins were 8 years; twins completed the same module at 13 years. Linear regression models tested for the concurrent and longitudinal associations between SOR and OCD controlling for socioeconomic status.

RESULTS

Concurrently, participants' likelihood of exhibiting OCD symptoms increased with each symptom of tactile or auditory overresponsivity at 8 years and 13 years (odds ratio = 1.1-2.7). However, SOR measured at age 8 years was unrelated to adolescent OCD symptoms at 13 years and vice versa.

CONCLUSION

SOR symptoms, although significantly related to concurrent OCD symptoms, do not appear to precede OCD symptoms, suggesting that SOR symptoms may reflect another type of OCD sensory phenomenon rather than a comorbid condition.

White matter microstructure correlates of general and specific second-order factors of psychopathology

Increasing data indicate that prevalent forms of psychopathology can be organized into second-order dimensions based on their correlations, including a general factor of psychopathology that explains the common variance among all disorders and specific second-order externalizing and internalizing factors. Nevertheless, most existing studies on the neural correlates of psychopathology employ case-control designs that treat diagnoses as independent categories, ignoring the highly correlated nature of psychopathology. Thus, for instance, although perturbations in white matter microstructure have been identified across a range of mental disorders, nearly all such studies used case-control designs, leaving it unclear whether observed relations reflect disorder-specific characteristics or transdiagnostic associations. Using a representative sample of 410 young adult twins oversampled for psychopathology risk, we tested the hypothesis that some previously observed relations between white matter microstructure properties in major tracts and specific disorders are related to second-order factors of psychopathology. We examined fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD). White matter correlates of all second-order factors were identified after controlling for multiple statistical tests, including the general factor (FA in the body of the corpus callosum), specific internalizing (AD in the fornix), and specific externalizing (AD in the splenium of the corpus callosum, sagittal stratum, anterior corona radiata, and internal capsule). These findings suggest that some features of white matter within specific tracts may be transdiagnostically associated multiple forms of psychopathology through second-order factors of psychopathology rather with than individual mental disorders.

Measuring longitudinal cognition: Individual tests versus composites

Introduction

Longitudinal cohort studies of cognitive aging must confront several sources of within-person variability in scores. In this article, we compare several neuropsychological measures in terms of longitudinal error variance and relationships with biomarker-assessed brain amyloidosis (Aβ).

Methods

Analyses used data from the Wisconsin Registry for Alzheimer's Prevention. We quantified within-person longitudinal variability and age-related trajectories for several global and domain-specific composites and their constituent scores. For a subset with cerebrospinal fluid or amyloid positron emission tomography measures, we examined how Aβ modified cognitive trajectories.

Results

Global and theoretically derived composites exhibited lower intraindividual variability and stronger age × Aβ interactions than did empirically derived composites or raw scores from single tests. For example, the theoretical executive function outperformed other executive function scores on both metrics.

Discussion

These results reinforce the need for careful selection of cognitive outcomes in study design, and support the emerging consensus favoring composites over single-test measures.

•

Identifying early cognitive change requires tests with low error variance.

•

In a middle-aged sample, composites were less noisy than single tests.

•

Global and theory-driven composites outperformed data-driven composites.

Sex Differences in the Genetic and Environmental Influences on Self-Reported Non-aggressive and Aggressive Conduct Disorder Symptoms in Early and Middle Adolescence

Decades of research into the etiology of conduct disorder (CD) has yet to yield a consensus on the existence of sex differences in underlying genetic and environmental influences. This may be partly due to the failure of many previous studies to make a distinction between non-aggressive and aggressive CD symptoms or test for potential developmental changes in sex differences in the etiology of conduct problems. To address these gaps, we fit a series of univariate and bivariate biometric sex-difference models to self-reported non-aggressive and aggressive CD symptoms in a community-based sample of twins (N = 1548, ages 9-17 year), grouped into ages 9-13 and 14-17 years. Relative model fit was evaluated using the Bayesian Information Criterion (BIC), which favors parsimony, and by Chi square difference tests. The univariate sex-scalar model provided the best fit to the data for both non-aggressive and aggressive CD symptoms at ages 9-13 and 14-17 years. Thus, the same genetic and environmental factors influenced CD symptoms in both sexes, but the total variability was lower in females than males. At both ages, the heritability of non-aggressive CD symptoms was lower than heritability of aggressive CD symptoms, and shared environmental effects were only observed for non-aggressive CD symptoms. However, estimates for genetic and environmental factors could be not be constrained to be equal across age groups for either CD subtype, suggesting substantive developmental changes in the relative influence of genetic and environmental factors on individual differences in CD symptoms. For both subtypes, the heritability was larger, and shared environmental effect smaller, in the older age group than the younger age group. A bivariate quantitative sex differences model provided the best fit to the data at ages 9-13 years. Covariation between non-aggressive and aggressive CD symptoms was due to overlapping shared and non-shared environmental factors in males and females but the overall covariation was greater in males than females. In contrast, at ages 14-17 years, the sex-scalar bivariate model provided the best fit to the data, and covariation between non-aggressive and aggressive CD symptoms was due to overlapping genetic and non-shared environmental factors. Thus, the etiology of self-reported conduct disorder varied substantially by symptom type and age. However, quantitative sex differences were only apparent when the covariation between the two subtypes was considered.

Brooding, Inattention, and Impulsivity as Predictors of Adolescent Suicidal Ideation

Although suicide remains a leading cause of death for adolescents, risk factors beyond diagnoses and suicide attempt history remain unclear. We examined whether cognitive style and temperament impact risk for an early, yet still clinically relevant and distressing, form of suicidality: active suicidal ideation. We used binary logistic regression to test whether brooding, inattention, and impulsivity predicted significantly increased risk for suicidal ideation in a sample of 134 twins, 46 of whom endorsed active suicidal ideation (i.e., probands), as well as probands' cotwins and matched controls. When comparing probands with controls and controlling for depression diagnoses, brooding (B = 0.73, Odds Ratio [OR] = 2.07, p = 0.021), inattention (B = 1.09, OR = 2.98, p < 0.001), and impulsivity (B = 0.91, OR = 2.47, p = 0.001) differentiated probands from controls, individually. We compared probands with their cotwins using the same approach, which allowed us to account for variance in suicidal ideation risk related to twins' shared, familial characteristics (e.g., prenatal environment, neighborhood); inattention was the only significant predictor of suicidal ideation risk (B = 0.66, OR = 1.93, p = 0.020). We then fit a logistic regression model that included all three predictors. Only inattention predicted significantly increased likelihood of suicidal ideation in proband versus controls and proband versus cotwin comparisons (B = 0.88, OR = 2.40, p = 0.024 and B = 0.67, OR = 1.96, p = 0.045, respectively). These results highlight the potential utility of examining novel, more proximal risk factors for suicidal ideation in addition to more established distal factors, like suicide attempt history and psychiatric diagnoses.

Measuring the hierarchical general factor model of psychopathology in young adults

There is evidence that models of psychopathology specifying a general factor and specific second-order factors fit better than competing structural models. Nonetheless, additional tests are needed to examine the generality and boundaries of the general factor model. In a selected second wave of a cohort study, first-order dimensions of psychopathology symptoms in 499 23- to 31-year-old twins were analyzed. Using confirmatory factor analysis, a bifactor model specifying a general factor and specific internalizing and externalizing factors fit better than competing models. Factor loadings in this model were sex invariant despite greater variances in the specific internalizing factor among females and greater variances in the general and specific externalizing factors among males. The bifactor structure was robust to the exclusion of any single first-order dimension of psychopathology. Furthermore, the results were essentially unchanged when all overlapping symptoms that define multiple disorders were excluded from symptom dimensions. Furthermore, the best-fitting bifactor model also emerged in exploratory structural equation modeling with freely estimated cross-loadings. The general factor of psychopathology was robust across variations in measurement and analysis.

Infant stranger fear trajectories predict anxious behaviors and diurnal cortisol rhythm during childhood

Although a robust literature has linked stable, high levels of fear across childhood to increased risk for anxiety problems, less is known about alternative pathways to anxiety. We tested two putatively normative developmental pathways of early fearfulness for their distinct associations with behavioral (anxiety-related behaviors and symptoms) and biological (diurnal cortisol) markers of anxiety risk in middle childhood in a community-based sample (n = 107). Steeper increases in fear from 6 to 36 months predicted more parent-reported anxiety symptoms at age 8 years. In addition, children who exhibited steep increases in fear during infancy were overrepresented among children with diagnoses of separation anxiety disorder at age 8 years. Finally, we showed that steeper increases in fearfulness in infancy predicted flatter slopes of diurnal cortisol at age 8 years for girls. Thus, differences in stranger fear across infancy may indicate varying degrees of risk for anxious behaviors in later childhood.

Genetic and Environmental Contributions to Associations between Infant Fussy Temperament and Antisocial Behavior in Childhood and Adolescence

Previous research suggests that fussy temperament in infancy predicts risk for later antisocial behavior (ASB) in childhood and adolescence. It remains unclear, however, to what extent infant fussiness is related to later ASB through causal processes or if they both reflect the same family risk factors for ASB. The current study used two approaches, the comparison of siblings and bivariate biometric modeling, to reduce familial confounding and examine genetic and environmental influences on associations between fussiness in the first 2 years of life and ASB in childhood and late adolescence. Analyses were conducted on data from a prospective cohort (9237 at 4-9 years and 7034 at 14-17 years) who are the offspring of a nationally representative sample of US women. In the full sample, fussiness predicted both child and adolescent ASB to small but significant extents, controlling for a wide range of measured child and family-level covariates. When siblings who differed in their fussiness were compared, fussiness predicted ASB in childhood, but not ASB during adolescence. Furthermore, results from a bivariate Cholesky model suggested that even the association of fussiness with childhood ASB found when comparing siblings is attributable to familial factors. That is, although families with infants who are higher in fussiness also tend to have children and adolescents who engage in greater ASB, the hypothesis that infant fussiness has an environmentally mediated impact on the development of future ASB was not strongly supported.

Partial replication of two rumination-related candidate gene studies

Two recent papers associated candidate genes with brooding rumination, a possible cognitive endophenotype for depression, in children ages 8-14 years. Stone et al. reported that BDNF val66met polymorphism predicted brooding in adolescence. Woody et al. reported that children carrying at least one copy of a CRHR1 TAT haplotype reported less brooding than their peers in the presence of maternal depression. We attempted to replicate and extend these findings in a sample of twins aged 12-16 years. We analyzed the BDNF val66met (rs6265) polymorphism and two (rs242924 and rs7209436) out of three single nucleotide polymorphisms (SNPs) that Woody et al. used to create a CRHR1 haplotype. We controlled for maternal history of depression and clustering within families. Unlike Stone et al., we found higher brooding among BDNF Met carriers. This main effect was qualified by an interaction with pubertal status, with the effect driven by more physically mature participants. Similar to Woody et al., we found an interaction between CRHR1 SNPs and maternal depression, with the homozygous minor genotype acting as a protective factor against brooding in the presence of maternal depression. Findings provide partial support for the influence of candidate genes in two environmentally sensitive systems on brooding.

Prospective association of childhood receptive vocabulary and conduct problems with self-reported adolescent delinquency: tests of mediation and moderation in sibling-comparison analyses

Associations among receptive vocabulary measured at 4-9 years, mother-reported childhood conduct problems at 4-9 years, and self-reported adolescent delinquency at 14-17 years were assessed using data from a prospective study of the offspring of a large U.S. nationally representative sample of women. A novel quasi-experimental strategy was used to rule out family-level confounding by estimating path-analytic associations within families in a sibling comparison design. This allowed simultaneous tests of the direct and indirect effects of receptive vocabulary and childhood conduct problems, and of their joint moderation, on adolescent delinquency without family-level environmental confounding. The significant association of receptive vocabulary with later adolescent delinquency was indirect, mediated by childhood conduct problems. Furthermore, a significant interaction between receptive vocabulary and childhood conduct problems reflected a steeper slope for the predictive association between childhood conduct problems and adolescent delinquency when receptive vocabulary scores were higher. These findings of significant indirect association were qualitatively identical in both population-level and within-family analyses, suggesting that they are not the result of family-level confounds.

Comparing Alternative Biometric Models with and without Gene-by-Measured Environment Interaction in Behavior Genetic Designs: Statistical Operating Characteristics

To extend Purcell's well known ACE model in testing gene by measured environment interactions (GxM) in behavior genetic designs, Rathouz et al. considered a broader class of models for quantifying and testing such interactions. Only a sub-group of these extended models have been investigated for their statistical operating characteristics by Van Hulle et al. due to lack of closed form likelihood. With an estimation procedure developed using numerical techniques in a companion paper, we study statistical operating characteristics of these extended models, especially those with non-linear effects. Type I error analysis shows the likelihood ratio test for GxM to be conservative in testing models extended from the bivariate Cholesky model, and to be liberal for models extended from the bivariate correlated factors model. Parameter estimation for all models is very good, with little bias exhibited for most models and parameters. Comparisons among alternative models under various simulated conditions show that it is relatively more difficult to confirm the existence of gene by environment interactions versus to detect non-linear effects which exclude such interactions.

Genetic and Environmental Contributions to Covariation Between DHEA and Testosterone in Adolescent Twins

Although several studies have shown that pubertal tempo and timing are shaped by genetic and environmental factors, few studies consider to what extent endocrine triggers of puberty are shaped by genetic and environmental factors. Doing so moves the field from examining correlated developmentally-sensitive biomarkers toward understanding what drives those associations. Two puberty related hormones, dehydroepiandrosterone and testosterone, were assayed from salivary samples in 118 MZ (62 % female), 111 same sex DZ (46 % female) and 103 opposite-sex DZ twin pairs, aged 12-16 years (M = 13.1, SD = 1.3). Pubertal status was assessed with a composite of mother- and self-reports. We used biometric models to estimate the genetic and environmental influences on the variance and covariance in testosterone and DHEA, with and without controlling for their association with puberty, and to test for sex differences. In males, the variance in testosterone and pubertal status was due to shared and non-shared environmental factors; variation in DHEA was due to genetic and non-shared environmental factors. In females, variance in testosterone was due to genetic and non-shared environmental factors; genetic, shared, and non-shared environmental factors contributed equally to variation in DHEA. In males, the testosterone-DHEA covariance was primarily due to shared environmental factors that overlapped with puberty as well as shared and non-shared environmental covariation specific to testosterone and DHEA. In females, the testosterone-DHEA covariance was due to genetic factors overlapping with pubertal status, and shared and non-shared environmental covariation specific to testosterone and DHEA.

Relative influence of genetics and shared environment on child mental health symptoms depends on comorbidity

Background

Comorbidity among childhood mental health symptoms is common in clinical and community samples and should be accounted for when investigating etiology. We therefore aimed to uncover latent classes of mental health symptoms in middle childhood in a community sample, and to determine the latent genetic and environmental influences on those classes.

Methods

The sample comprised representative cohorts of twins. A questionnaire-based assessment of mental health symptoms was used in latent class analyses. Data on 3223 twins (1578 boys and 1645 girls) with a mean age of 7.5 years were analyzed. The sample was predominantly non-Hispanic Caucasian (92.1%).

Results

Latent class models delineated groups of children according to symptom profiles–not necessarily clinical groups but groups representing the general population, most with scores in the normative range. The best-fitting models suggested 9 classes for both girls and boys. Eight of the classes were very similar across sexes; these classes ranged from a “Low Symptom” class to a “Moderately Internalizing & Severely Externalizing” class. In addition, a “Moderately Anxious” class was identified for girls but not boys, and a “Severely Impulsive & Inattentive” class was identified for boys but not girls. Sex-combined analyses implicated moderate genetic influences for all classes. Shared environmental influences were moderate for the “Low Symptom” and “Moderately Internalizing & Severely Externalizing” classes, and small to zero for other classes.

Conclusions

We conclude that symptom classes are largely similar across sexes in middle childhood. Heritability was moderate for all classes, but shared environment played a greater role for classes in which no one type of symptom predominated.

A sibling-comparison study of smoking during pregnancy and childhood psychological traits

Prenatal exposure to substances of abuse is associated with numerous psychological problems in offspring, but quasi-experimental studies controlling for co-occurring risk factors suggest that familial factors (e.g., genetic and environmental effects shared among siblings) confound many associations with maternal smoking during pregnancy (SDP). Few of the quasi-experimental studies in this area have explored normative psychological traits in early childhood or developmental changes across the lifespan, however. The current study used multilevel growth curve models with a large, nationally-representative sample in the United States to investigate for potential effects of SDP on the developmental trajectories of cognitive functioning, temperament/personality, and disruptive behavior across childhood, while accounting for shared familial confounds by comparing differentially exposed siblings and statistically controlling for offspring-specific covariates. Maternal SDP predicted the intercept (but not change over time) for all cognitive and externalizing outcomes. Accounting for familial confounds, however, attenuated the association between SDP exposure and all outcomes, except the intercept (age 5) for reading recognition. These findings, which are commensurate with previous quasi-experimental research on more severe indices of adolescent and adult problems, suggest that the associations between SDP and developmental traits in childhood are due primarily to confounding factors and not a causal association.

Effects of multiple maternal relationship transitions on offspring antisocial behavior in childhood and adolescence: a cousin-comparison analysis

Previous studies of the association between multiple parental relationship transitions (i.e., when a parent begins or terminates an intimate relationship involving cohabitation) and offspring antisocial behavior have varied in their efforts to rule out confounding influences, such as parental antisocial behavior and low income. They also have been limited in the representativeness of their samples. Thus, it remains unclear to what degree parents' multiple relationship transitions have independent effects on children's antisocial behavior. Analyses were conducted using data on 8,652 6-9-year-old, 6,911 10-13-year-old, and 6,495 14-17-year-old offspring of a nationally representative sample of U.S. women. Cousin-comparisons were used in combination with statistical covariates to evaluate the associations between maternal relationship transitions and offspring antisocial behavior in childhood and adolescence. Cousin-comparisons suggested that associations between maternal relationship transitions and antisocial behavior in childhood and early adolescence are largely explained by confounding factors. In contrast, the associations between maternal relationship transitions and offspring delinquency in late adolescence were robust to measured and unmeasured confounds. The present findings suggest that interventions aimed at reducing exposure to parental relationship transitions or addressing the psychosocial consequences of exposure to parental relationship transitions could reduce risk for offspring delinquency in late adolescence.

Genetic and Environmental Influences on Rumination, Distraction, and Depressed Mood in Adolescence

Rumination is an established cognitive vulnerability for depression. Despite substantial work on the environmental origins of rumination, the heritability of rumination has not been examined and it is not known whether rumination accounts for some of the genetic vulnerability associated with depression. 756 adolescent twins ages 12-14 years completed the Response Styles Questionnaire and multiple measures of depressive symptoms. Brooding correlated positively and distraction correlated negatively with concurrent depressive symptoms. Estimated heritabilites were 54% for depression, 21% for brooding, 37% for reflection, and 30% for distraction. Bivariate genetic analyses suggested that (1) individual differences in distraction share both genetic and environmental sources of variation with depression; and (2) although the heritable influences on brooding are small, these heritable influences account for the majority of the relationship between brooding and depression (h2 = .62).

Language ability predicts the development of behavior problems in children

Prior studies have suggested, but not fully established, that language ability is important for regulating attention and behavior. Language ability may have implications for understanding attention-deficit hyperactivity disorder (ADHD) and conduct disorders, as well as subclinical problems. This article reports findings from two longitudinal studies to test (a) whether language ability has an independent effect on behavior problems, and (b) the direction of effect between language ability and behavior problems. In Study 1 (N = 585), language ability was measured annually from ages 7 to 13 years by language subtests of standardized academic achievement tests administered at the children's schools. Inattentive-hyperactive (I-H) and externalizing (EXT) problems were reported annually by teachers and mothers. In Study 2 (N = 11,506), language ability (receptive vocabulary) and mother-rated I-H and EXT problems were measured biannually from ages 4 to 12 years. Analyses in both studies showed that language ability predicted within-individual variability in the development of I-H and EXT problems over and above the effects of sex, ethnicity, socioeconomic status (SES), and performance in other academic and intellectual domains (e.g., math, reading comprehension, reading recognition, and short-term memory [STM]). Even after controls for prior levels of behavior problems, language ability predicted later behavior problems more strongly than behavior problems predicted later language ability, suggesting that the direction of effect may be from language ability to behavior problems. The findings suggest that language ability may be a useful target for the prevention or even treatment of attention deficits and EXT problems in children.

Early concern and disregard for others as predictors of antisocial behavior

BACKGROUND

Prediction of antisocial behavior is important, given its adverse impact on both the individuals engaging in antisocial behavior and society. Additional research identifying early predictors of future antisocial behavior, or antisocial propensity, is needed. The present study tested the hypothesis that both concern for others and active disregard for others in distress in toddlers and young children predict antisocial behavior during middle childhood and adolescence.

METHODS

A representative sample of same-sex twins (N=956) recruited in Colorado was examined. Mother-rated and researcher-observed concern and disregard for others assessed at age 14-36 months were examined as predictors of parent- (age 4-12), teacher- (age 7-12), and self-reported (age 17) antisocial behavior.

RESULTS

  Observed disregard for others predicted antisocial behavior assessed by three different informants (parents, teachers, and self), including antisocial behavior assessed 14 years later. It also predicted a higher order antisocial behavior factor (β=.58, p<.01) after controlling for observed concern for others. Mother-rated disregard for others predicted parent-reported antisocial behavior. Contrary to predictions, neither mother-rated nor observed concern for others inversely predicted antisocial behavior. RESULTS of twin analyses suggested that the covariation between observed disregard for others and antisocial behavior was due to shared environmental influences.

CONCLUSIONS

Disregard for others in toddlerhood/early childhood is a strong predictor of antisocial behavior in middle childhood and adolescence. The results suggest the potential need for early assessment of disregard for others and the development of potential interventions.

The role of language in concern and disregard for others in the first years of life

We examined the associations between language skills and concern and disregard for others in young children assessed longitudinally at ages 14, 20, 24, and 36 months, testing the hypothesis that language skills have a specific role (distinct from that of general cognitive ability) in the development of concern and disregard for others. We found that higher language skills predicted higher concern for others and lower disregard for others even after controlling for general cognitive ability, whereas the association between general cognitive ability and concern/disregard for others was not significant after controlling for language skills. Language skills at 14 months predicted concern for others at 36 months, and results suggested that the relations between language skills and concern and disregard for others begin early in development. Gender differences in concern and disregard for others were at least partially explained by differences in language skills. These results support the specific role of language skills in concern and disregard for others.

Familial confounding of the association between maternal smoking during pregnancy and offspring substance use and problems

CONTEXT

Previous epidemiological, animal, and human cognitive neuroscience research suggests that maternal smoking during pregnancy (SDP) causes increased risk of substance use/problems in offspring.

OBJECTIVE

To determine the extent to which the association between SDP and offspring substance use/problems depends on confounded familial background factors by using a quasi-experimental design.

DESIGN

We used 2 separate samples from the United States and Sweden. The analyses prospectively predicted multiple indices of substance use and problems while controlling for statistical covariates and comparing differentially exposed siblings to minimize confounding.

SETTING

Offspring of a representative sample of women in the United States (sample 1) and the total Swedish population born during the period from January 1, 1983, to December 31, 1995 (sample 2).

PATIENTS OR OTHER PARTICIPANTS

Adolescent offspring of the women in the National Longitudinal Survey of Youth 1979 (n = 6904) and all offspring born in Sweden during the 13-year period (n = 1,187,360).

MAIN OUTCOME MEASURES

Self-reported adolescent alcohol, cigarette, and marijuana use and early onset (before 14 years of age) of each substance (sample 1) and substance-related convictions and hospitalizations for an alcohol- or other drug-related problem (sample 2).

RESULTS

The same pattern emerged for each index of substance use/problems across the 2 samples. At the population level, maternal SDP predicted every measure of offspring substance use/problems in both samples, ranging from adolescent alcohol use (hazard ratio [HR](moderate), 1.32 [95% CI, 1.22-1.43]; HR(high), 1.33 [1.17-1.53]) to a narcotics-related conviction (HR(moderate), 2.23 [2.14-2.31]; HR(high), 2.97 [2.86-3.09]). When comparing differentially exposed siblings to minimize genetic and environmental confounds, however, the association between SDP and each measure of substance use/problems was minimal and not statistically significant.

CONCLUSIONS

The association between maternal SDP and offspring substance use/problems is likely due to familial background factors, not a causal influence, because siblings have similar rates of substance use and problems regardless of their specific exposure to SDP.

Operating characteristics of alternative statistical methods for detecting gene-by-measured environment interaction in the presence of gene-environment correlation in twin and sibling studies

It is likely that all complex behaviors and diseases result from interactions between genetic vulnerabilities and environmental factors. Accurately identifying such gene-environment interactions is of critical importance for genetic research on health and behavior. In a previous article we proposed a set of models for testing alternative relationships between a phenotype (P) and a putative moderator (M) in twin studies. These include the traditional bivariate Cholesky model, an extension of that model that allows for interactions between M and the underling influences on P, and a model in which M has a non-linear main effect on P. Here we use simulations to evaluate the type I error rates, power, and performance of the Bayesian Information Criterion under a variety of data generating mechanisms and samples sizes (n = 2,000 and n = 500 twin pairs). In testing the extension of the Cholesky model, false positive rates consistently fell short of the nominal Type I error rates ([Formula: see text]). With adequate sample size (n = 2,000 pairs), the correct model had the lowest BIC value in nearly all simulated datasets. With lower sample sizes, models specifying non-linear main effects were more difficult to distinguish from models containing interaction effects. In addition, we provide an illustration of our approach by examining possible interactions between birthweight and the genetic and environmental influences on child and adolescent anxiety using previously collected data. We found a significant interaction between birthweight and the genetic and environmental influences on anxiety. However, the interaction was accounted for by non-linear main effects of birthweight on anxiety, verifying that interaction effects need to be tested against alternative models.

Genetic and environmental influences on individual differences in cortisol level and circadian rhythm in middle childhood

Individuals differ widely in cortisol output over the day, but the etiology of these individual differences remains poorly understood. Twin studies are useful for quantifying genetic and environmental influences on the variation in cortisol output, lending insight into underlying influences on the components of Hypothalamic-Pituitary-Adrenal (HPA) axis functioning. Salivary cortisol was assayed on 446 twin pairs (157 monozygotic, 289 dizygotic; ages 7-8). Parents helped youth collect saliva 30 min after waking, mid-afternoon, and 30 min prior to bedtime across 3 consecutive days. We used hierarchical linear modeling to extract predicted cortisol levels and to distinguish cortisol's diurnal rhythm using a slopes-as-outcome piecewise growth curve model; two slopes captured the morning-to-afternoon and afternoon-to-evening rhythm, respectively. Separate genetic models were then fit to cortisol level at waking, mid-afternoon, and evening as well as the diurnal rhythm across morning-to-afternoon and afternoon-to-evening hours. Three results from these analyses are striking. First, morning-to-afternoon cortisol level showed the highest additive genetic variance (heritability), consistent with prior research. Second, cortisol's diurnal rhythm had an additive genetic component, particularly across the morning-to-afternoon hours. In contrast, additive genetic variation did not significantly contribute to variation in afternoon-to-evening slope. Third, the majority of variance in cortisol concentration was associated with shared family environments. In summary, both genetic and environmental factors influence cortisol's circadian rhythm, and they do so differentially across the day.

Wisconsin Twin Panel: Current Directions and Findings

The Wisconsin Twin Panel is based on the population of all twins born in the state of Wisconsin, United States. Our research focus is the etiology and developmental course of early emotions, temperament, childhood anxiety and impulsivity, the autism spectrum, auditory and tactile sensory sensitivity, and related psychobiological and behavioral phenotypes. We employ a range of research methods including structured interviews with caregivers, observer ratings, child self-report, home-based behavioral batteries, biological measures of basal and reactive cortisol, palm prints, birth records, genotyping, cognitive testing, and questionnaires. Reported results highlight the utility of employing multiple modes of assessment when studying child development and psychopathology.

Is sensory over-responsivity distinguishable from childhood behavior problems? A phenotypic and genetic analysis

BACKGROUND

Although impaired sensory processing accompanies various clinical conditions, the question of its status as an independent disorder remains open. Our goal was to delineate the comorbidity (or lack thereof) between childhood psychopathology and sensory over-responsivity (SOR) in middle childhood using phenotypic and behavior-genetic analyses.

METHOD

Participants (N = 970) were drawn from the Wisconsin Twin Project, a population-based sample of twins and their families. Mothers completed a sensory responsivity checklist when their offspring were on average 7 years old, followed by a diagnostic interview (Diagnostic Interview Schedule for Children; DISC) within 6-12 months. We examined the incidence of DISC diagnoses - attention deficit hyperactivity disorder, conduct disorder, oppositional defiant disorder, agoraphobia, general anxiety, obsessive-compulsive disorder, panic disorder, separation anxiety, social phobia, specific phobia, depression, enuresis, trichtollomaniatics, selective mutism, and pica - among children with SOR, and vice versa. Children with autism or pervasive developmental disorders were excluded from the present study. In addition, we examined parent-reported physical health diagnoses among nondiagnosed children and three groups of children with SOR and/or DISC diagnoses. Biometric models explored common underlying genetic and environmental influences on symptoms of SOR and psychopathology.

RESULTS

A majority of individuals who screened positive for SOR did not qualify for a DISC diagnosis (58.2%), and vice versa (68.3%). Children who screened positive for SOR only and typical children had similar rates of physical health problems. Turning to a dimensional approach, multivariate twin models demonstrated that modest covariation between SOR and DISC symptoms could be entirely accounted for by common underlying genetic effects.

CONCLUSIONS

Our results suggest that SOR occurs independently of recognized childhood psychiatric diagnoses but is also a relatively frequent comorbid condition with recognized diagnoses. Genetic sources of this comorbidity are implicated.

A quasi-experimental analysis of the influence of neighborhood disadvantage on child and adolescent conduct problems

A quasi-experimental comparison of cousins differentially exposed to levels of neighborhood disadvantage (ND) was used with extensive measured covariates to test the hypothesis that neighborhood risk has independent effects on youth conduct problems (CPs). Multilevel analyses were based on mother-rated ND and both mother-reported CPs across 4-13 years (n = 7,077) and youth-reported CPs across 10-13 years (n = 4,524) from the Children of the National Longitudinal Survey of Youth. ND was robustly related to CPs reported by both informants when controlling for both measured risk factors that are correlated with ND and unmeasured confounds. These findings are consistent with the hypothesis that ND has influence on conduct problems.

Shared genetic influences on negative emotionality and major depression/conduct disorder comorbidity

OBJECTIVE

To investigate whether genetic contributions to major depressive disorder and conduct disorder comorbidity are shared with genetic influences on negative emotionality.

METHOD

Primary caregivers of 2,022 same- and opposite-sex twin pairs 6 to 18 years of age comprised a population-based sample. Participants were randomly selected across five regions in Tennessee, with stratification by age and geographic location. Face-to-face structured interviews were conducted with the primary caregiver of a representative sample of twins.

RESULTS

After accounting for genetic influences on negative emotionality, genetic influences on major depressive disorder/conduct disorder comorbidity were nonsignficant, but only in male twins. Specifically, 19% of the variance in the two disorders was accounted for by genetic factors shared with negative emotionality in male twins. Although the full hypothesis could not be tested in female twins, 10% to 11% of the variance in the two disorders was also accounted for by genetic factors shared with negative emotionality. Common shared environmental and nonshared environmental influences were found for major depressive disorder/conduct disorder comorbidity in male and female twins.

CONCLUSIONS

Negative emotionality represents an important dispositional trait that may explain genetic influences on major depressive disorder/conduct disorder comorbidity, at least for boys. Models of major depressive disorder/conduct disorder comorbidity must simultaneously measure common and specific genetic and environmental factors for a full understanding of this phenomenon. Gender differences require specific research attention in dispositional factors and developmental progression.

Deriving childhood temperament measures from emotion-eliciting behavioral episodes: scale construction and initial validation

The authors describe the development and initial validation of a home-based version of the Laboratory Temperament Assessment Battery (Lab-TAB), which was designed to assess childhood temperament with a comprehensive series of emotion-eliciting behavioral episodes. This article provides researchers with general guidelines for assessing specific behaviors using the Lab-TAB and for forming behavioral composites that correspond to commonly researched temperament dimensions. We used mother ratings and independent postvisit observer ratings to provide validity evidence in a community sample of 4.5-year-old children. 12 Lab-TAB behavioral episodes were employed, yielding 24 within-episode temperament components that collapsed into 9 higher level composites (Anger, Sadness, Fear, Shyness, Positive Expression, Approach, Active Engagement, Persistence, and Inhibitory Control). These dimensions of temperament are similar to those found in questionnaire-based assessments. Correlations among the 9 composites were low to moderate, suggesting relative independence. As expected, agreement between Lab-TAB measures and postvisit observer ratings was stronger than agreement between the Lab-TAB and mother questionnaire. However, for Active Engagement and Shyness, mother ratings did predict child behavior in the Lab-TAB quite well. Findings demonstrate the feasibility of emotion-eliciting temperament assessment methodologies, suggest appropriate methods for data aggregation into trait-level constructs and set some expectations for associations between Lab-TAB dimensions and the degree of cross-method convergence between the Lab-TAB and other commonly used temperament assessments.

Higher-order genetic and environmental structure of prevalent forms of child and adolescent psychopathology

CONTEXT

It is necessary to understand the etiologic structure of child and adolescent psychopathology to advance theory and guide future research.

OBJECTIVE

To test alternative models of the higher-order structure of etiologic effects on 11 dimensions of child and adolescent psychopathology using confirmatory factor analyses of genetic and environmental covariances.

DESIGN

Representative sample of twins.

SETTING

Home interviews.

PARTICIPANTS

A total of 1571 pairs of 9- to 17-year-old twins.

MAIN OUTCOME MEASURES

Structured assessments of psychopathology using adult caregivers and youth as informants.

RESULTS

The best-fitting genetic model revealed that most genetic factors nonspecifically influence risk for either all 11 symptom dimensions or for dimensions of psychopathology within 1 of 2 broad domains. With some notable exceptions, dimension-specific genetic influences accounted for modest amounts of variance.

CONCLUSIONS

To inform theory and guide molecular genetic studies, an etiologic model is offered in which 3 patterns of pleiotropy are hypothesized to be the principal modes of genetic risk transmission for common forms of child and adolescent psychopathology. Some common environmental influences were found, but consistent with a "generalist genes, specialist environments" model, there was little sharing of environmental influences. This implies that prevalent dimensions of child and adolescent psychopathology mostly share their genetic liabilities but are differentiated by nonshared experiences.

Associations between father absence and age of first sexual intercourse

Children raised without a biological father in the household have earlier average ages of first sexual intercourse than children raised in father-present households. Competing theoretical perspectives have attributed this either to effects of father absence on socialization and physical maturation or to nonrandom selection of children predisposed for early sexual intercourse into father-absent households. Genetically informative analyses of the children of sister dyads (N = 1,382, aged 14-21 years) support the selection hypothesis: This association seems attributable to confounded risks, most likely genetic in origin, which correlated both with likelihood of father absence and early sexual behavior. This holds implications for environmental theories of maturation and suggests that previous research may have inadvertently overestimated the role of family structure in reproductive maturation.

Developmental structure of genetic influences on antisocial behavior across childhood and adolescence

It is necessary to determine if causal influences on developing antisocial behavior change with age to guide both research and theory on its origins. The extent to which the same genetic factors influence antisocial behavior across 4-17 years of age was estimated using 2,482 sibling pairs of varying genetic relatedness. Assessments of antisocial behavior by mothers (4-9 years), mothers and youth (10-13 years), and youth (14-17 years) reflected the changing validity of informants across development. Genetic influences on antisocial behavior at 14-17 years were entirely shared with those on antisocial behavior at 10-13 years according to both informants. Genetic influences on antisocial behavior at 14-17 years were distinct from those at 4-9 years, however. These age differences in genetic influences cannot be fully distinguished from informant differences across age, but the present findings indicate that youth reported to be persistently antisocial during childhood and adolescence are influenced by one set of genetic factors influencing parent-report conduct problems in childhood and a second set of genetic influences on youth-reported delinquency that come into play around the time of the pubertal transition.

Maternal age at childbirth and offspring disruptive behaviors: testing the causal hypothesis

BACKGROUND

Recent studies suggest that the association between maternal age at childbearing (MAC) and children's disruptive behaviors is the result of family factors that are confounded with both variables, rather than a casual effect of environmental factors specifically related to MAC. These studies, however, relied on restricted samples and did not use the strongest approach to test causal influences.

METHODS

Using data on 9,171 4-9-year-old and 6,592 10-13-year-old offspring of women from a nationally representative sample of US households, we conducted sibling-comparison analyses. The analyses ruled out all genetic factors that could confound the association, as well as all environmental confounds that differ between unrelated nuclear families, providing a strong test of the causal hypothesis that the environments of children born at different maternal ages influence mother- and self-reported disruptive behaviors.

RESULTS

When these genetic and environmental confounds were ruled out as alternative explanations, the relation between environments within nuclear families specifically associated with MAC and disruptive behaviors was robust, with the association being stronger for second- and third-born children.

CONCLUSIONS

Environmental factors specifically associated with early MAC within nuclear families account for increased risk of offspring disruptive behaviors, especially in later-born children.

A quasi-experimental analysis of the association between family income and offspring conduct problems

The study presents a quasi-experimental analysis of data on 9,194 offspring (ages 4-11 years old) of women from a nationally representative U.S. sample of households to test the causal hypotheses about the association between family income and childhood conduct problems (CPs). Comparison of unrelated individuals in the sample indicated a robust inverse association, with the relation being larger at higher levels of income and for male offspring, even when statistical covariates were included to account for measured confounds that distinguish different families. Offspring also were compared to their siblings and cousins who were exposed to different levels of family income in childhood to rule out unmeasured environmental and genetic factors confounded with family income as explanations for the association. In these within-family analyses, boys exposed to lower family income still exhibited significantly higher levels of CPs. When considered in the context of previous studies using different designs, these results support the inference that family income influences CPs, particularly in males, through causal environmental processes specifically related to earnings within the nuclear family.

Are oppositional-defiant and hyperactive-inattentive symptoms developmental precursors to conduct problems in late childhood?: genetic and environmental links

Inattentive-hyperactive and oppositional behavior have been hypothesized to be developmental precursors to conduct problems. We tested these hypotheses using a longitudinal sample of 6,466 offspring of women selected from nationally representative US households. Conduct problems across 8-13 years were robustly predicted by conduct problems at 4-7 years, but also were independently predicted to a small extent by both inattentive-hyperactive and oppositional behaviors at 4-7 years. Longitudinal multivariate behavior genetic analyses revealed that the genetic and environmental factors that influence conduct problems at both 4-7 and 8-13 years also influence the putative precursors at 4-7 years. After genetic and environmental influences on conduct problems at 4-7 years were taken into account, however, inattentive-hyperactive and oppositional behavior at 4-7 years shared causal influences with conduct problems 8-13 years to a negligible extent. These findings suggest that after early conduct problems are controlled, little is gained in terms of prediction or understanding genetic and environmental influences on later child conduct problems by treating early inattentive-hyperactive and oppositional behavior as developmental precursors to later conduct problems.

Temperament and parenting during the first year of life predict future child conduct problems

Predictive associations between parenting and temperament during the first year of life and child conduct problems were assessed longitudinally in 1,863 offspring of a representative sample of women. Maternal ratings of infant fussiness, activity level, predictability, and positive affect each independently predicted maternal ratings of conduct problems during ages 4-13 years. Furthermore, a significant interaction indicated that infants who were both low in fussiness and high in predictability were at very low risk for future conduct problems. Fussiness was a stronger predictor of conduct problems in boys whereas fearfulness was a stronger predictor in girls. Conduct problems also were robustly predicted by low levels of early mother-report cognitive stimulation when infant temperament was controlled. Interviewer-rated maternal responsiveness was a robust predictor of conduct problems, but only among infants low in fearfulness. Spanking during infancy predicted slightly more severe conduct problems, but the prediction was moderated by infant fussiness and positive affect. Thus, individual differences in risk for mother-rated conduct problems across childhood are already partly evident in maternal ratings of temperament during the first year of life and are predicted by early parenting and parenting-by-temperament interactions.

Specification, testing, and interpretation of gene-by-measured-environment interaction models in the presence of gene-environment correlation

Purcell (Twin Res 5:554-571, 2002) proposed a bivariate biometric model for testing and quantifying the interaction between latent genetic influences and measured environments in the presence of gene-environment correlation. Purcell's model extends the Cholesky model to include gene-environment interaction. We examine a number of closely related alternative models that do not involve gene-environment interaction but which may fit the data as well as Purcell's model. Because failure to consider these alternatives could lead to spurious detection of gene-environment interaction, we propose alternative models for testing gene-environment interaction in the presence of gene-environment correlation, including one based on the correlated factors model. In addition, we note mathematical errors in the calculation of effect size via variance components in Purcell's model. We propose a statistical method for deriving and interpreting variance decompositions that are true to the fitted model.

Sex differences in the causes of self-reported adolescent delinquency

Sex differences in the causes of self-reported adolescent delinquency were examined in full and half siblings born to a nationally representative sample of women in the United States. Qualitative sex differences in the genes that influence delinquency were not detected. Similarly, the proportions of variance in both aggressive and nonaggressive delinquency attributable to genetic and environmental influences did not differ significantly between girls and boys. Nonetheless, total variance in delinquency was greater among boys, and a scalar sex-differences model suggested that genetic and environmental influences on delinquency have less effect on population variation in delinquency among girls. Similarly, a test of the polygenic multiple threshold model suggested that girls require greater causal liability for the expression of delinquency than boys.

Association of dopamine transporter genotype with disruptive behavior disorders in an eight-year longitudinal study of children and adolescents

Associations between dopamine transporter (DAT1) variable number tandem repeats (VNTR), genotypes, and disruptive behavior were examined in an 8-year longitudinal study of children (n = 183). Half of the children met criteria for attention-deficit/hyperactivity disorder (ADHD) at 4-6 years and half were non-referred comparison children. Consistent with several studies, the non-additive association for the 10-repeat allele was significant for hyperactivity-impulsivity (HI) symptoms. However, consistent with other studies, exploratory analyses of the non-additive association of the 9-repeat allele of DAT1 with HI and oppositional defiant disorder (ODD) symptoms also were significant. The inconsistent association between DAT1 and child behavior problems in this and other samples may reflect joint influence of the 10-repeat and 9-repeat alleles.

Wisconsin Twin Panel: current directions and findings

The Wisconsin Twin Panel is based on the population of all twins born in the state of Wisconsin, United States. Our research focus is the etiology and developmental course of early emotions, temperament, childhood anxiety and impulsivity, the autism spectrum, auditory and tactile sensory sensitivity, and related psychobiological and behavioral phenotypes. We employ a range of research methods including structured interviews with caregivers, observer ratings, child self-report, home-based behavioral batteries, biological measures of basal and reactive cortisol, palm prints, birth records, genotyping, cognitive testing, and questionnaires. Reported results highlight the utility of employing multiple modes of assessment when studying child development and psychopathology.