Obstetrical and neonatal complications, prematurity, and childhood effortful control development: A longitudinal twin study.

Premature infants may be at risk for lower effortful control, and subsequent lower academic achievement, peer competence, and emotional and physical wellness throughout the lifespan. However, because prematurity is related to obstetrical and neonatal complications, it is unclear what may drive the effect. Effortful control also has a strong heritable component; therefore, environmental factors during pregnancy and the neonatal period may interact with genetic factors to predict effortful control development. In this study, we aimed to dissect the influences of genetics, prematurity, and neonatal and obstetrical complications on the development of effortful control from 12 months to 10 years using a twin cohort. This study used data from the Arizona Twin Project, an ongoing longitudinal study of approximately 350 pairs of twins. Twins were primarily Hispanic/Latinx (23.8%-27.1%) and non-Hispanic/Latinx White (53.2%-57.8%), and families ranged in socioeconomic status with around one third falling below or near the poverty line. Of the twins, 62.6% were born prematurely. Effortful control was assessed via parent report at six waves. There was not a significant relationship between gestational age and effortful control regardless of whether obstetrical and neonatal complications were controlled for. Biometric twin modeling revealed that the attentional focusing subdomain of effortful control was highly heritable. Gestational age did not moderate genetic and environmental estimates. Our findings help inform the risk assessment of prematurity and provide evidence for the differing etiology of each subdomain of effortful control and the strong role of genetics in effortful control development. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

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

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

Cascading Influences of Caregiver Experiences of Discrimination and Adolescent Antisocial Behavior.

OBJECTIVE: Although a growing body of work has found that parents' experiences of racial and socioeconomic (SES) based discrimination are directly related to their children's behavior problems , more work is needed to understand possible pathways by which these factors are related and to identify potential targets for prevention and/or intervention. METHOD: Using a large (N = 572), longitudinal sample of low-income families from diverse racial backgrounds, the current study explored whether caregivers' experiences of racial and SES discrimination during their children's middle childhood (i.e. ages 7.5-9.5) predicted youth-reported antisocial behavior during adolescence and potential factors mediating these associations (e.g. caregiver depressive symptoms and positive parenting practices). RESULTS: We found that higher levels of caregiver experiences of discrimination at child ages 7.5-9.5 predicted higher levels of caregiver depressive symptoms at child age 10.5, which were related to lower levels of caregiver endorsement of positive parenting practices at child age 14.5, which in turn, predicted higher levels of youth-reported antisocial behavior at age 16. CONCLUSION: The findings highlight the adverse effects of racism and discrimination in American society. Second, the findings underscore the need to develop interventions which mitigate racism and discrimination among perpetrators and alleviate depressive symptoms among caregivers.

Alcohol Use Disorder Polygenic Risk Scores and Trajectories of Early Adolescent Externalizing Behaviors: Examining the Role of Parenting and Family Conflict in the Racially/Ethnically Diverse ABCD Sample.

This study examined the independent and interactive effects of alcohol use disorder genome-wide polygenic scores (AUD-PGS) and parenting and family conflict on early adolescent externalizing behaviors. Data were drawn from White (N = 6181, 46.9% female), Black/African American (N = 1784, 50.1% female), and Hispanic/Latinx (N = 2410, 48.0% female) youth from the adolescent brain cognitive development Study (ABCD). Parents reported on youth externalizing behaviors at baseline (T1, age 9/10), 1-year (T2, age 10/11) and 2-year (T3, age 11/12) assessments. Youth reported on parenting and family environment at T1 and provided saliva or blood samples for genotyping. Results from latent growth models indicated that in general externalizing behaviors decreased from T1 to T3. Across all groups, higher family conflict was associated with more externalizing behaviors at T1, and we did not find significant associations between parental monitoring and early adolescent externalizing behaviors. Parental acceptance was associated with lower externalizing behaviors among White and Hispanic youth, but not among Black youth. Results indicated no significant main effect of AUD-PGS nor interaction effect between AUD-PGS and family variables on early adolescent externalizing behaviors. Post hoc exploratory analysis uncovered an interaction between AUD-PGS and parental acceptance such that AUD-PGS was positively associated with externalizing rule-breaking behaviors among Hispanic youth, but only when parental acceptance was very low. Findings highlight the important role of family conflict and parental acceptance in externalizing behaviors among early adolescents, and emphasize the need to examine other developmental pathways underlying genetic risk for AUD across diverse populations.

How pubertal timing and self-regulation predict adolescent sexual activity in resource-poor environments.

Studies found support for a link between pubertal timing and self-regulation in low-resource environments. This link could potentially explain a link between pubertal timing and early risk behavior. This study builds on this body of research by examining the mediated effect of pubertal timing on sexual activity through self-regulation in 728 adolescents and their families in a group with poor resources and a group with adequate resources. Income-to-Needs (ITN) was measured at age 7.5 to establish two groups (low-ITN and Medium/High-ITN). Pubertal timing was measured at age 10.5, self-regulation was assessed at age 14 and operationalized with effortful control, and sexual activity was assessed at age 16. Structural equation modeling was employed to test the hypothesized model in both groups. The link between pubertal timing and sexual activity mediated by effortful control was only significant in the low-ITN group. Specifically, more advanced pubertal maturity was associated with lower levels of adolescents' effortful control, which in turn was associated with more sexual activity at age 16. Findings were partially replicated with a drug use index replacing sexual activity. This study shows a different operating link from pubertal timing to effortful control and subsequent risk behavior in resource-poor environments. Implications are discussed.

Concordance in parent-child and sibling actigraphy-measured sleep: Evidence among early adolescent twins and primary caregivers.

STUDY OBJECTIVES: Growing evidence suggests concordance between parent and youth sleep. However, no known study has simultaneously examined concordance among siblings' sleep patterns. This study investigated daily and average concordance in (1) parent-youth and (2) sibling actigraphy-measured sleep, as well as the degree to which sibling concordance varied by sleeping arrangements. METHODS: 516 twin siblings (Mage = 10.74, 51% female; 30% monozygotic (MZ) twin pairs, 37% same-sex dizygotic pairs (DZ-ss), 33% opposite-sex DZ pairs (DZ-os)) and their primary caregivers (Mage = 40.59, 95% female) wore wrist-based accelerometers for 7 consecutive nights to measure sleep duration, efficiency, midpoint time, and latency. Primary caregivers also reported on demographics, youth pubertal status, and room-sharing. Two-level multilevel models were estimated to examine daily and average concordance in parent-youth and sibling sleep. RESULTS: Daily concordance was observed between parent and youth sleep duration and midpoint; average concordance was found for sleep duration, midpoint, and latency. Within sibling dyads, daily and average concordance was evident across all sleep parameters (duration, efficiency, midpoint, latency), with generally stronger concordance patterns for MZ than DZ twin pairs, and for twins who shared a room with their co-twin. CONCLUSIONS: This is the first known study to document concordance among parent-youth and siblings' actigraphy-measured sleep within the same study (i.e., triad). Our findings can help inform the development of family-level interventions targeting daily and overall sleep hygiene.

Novel measures of family orientation and childhood self-regulation: A genetically informed twin study.

There is a dearth of research examining the relation between culture and childhood self-regulation in family psychology. Family orientation refers to the emphasis on providing support, respect, and obligation to the family system, and it is important for children's functioning, yet existing literature on related constructs often relies on parent-reported measures. Additionally, twin research has neglected the role of culture in the genetic and environmental contributions to children's self-regulation. Using observational and self-reported data from children, parents, and teachers, this study (a) proposed novel coding schemes and factor analytic approaches to capture family orientation, (b) examined associations between family orientation and self-regulation, and (c) tested whether family orientation moderated the heritability of self-regulation in middle childhood. Twin children (N = 710; Mage = 8.38 years, SD = 0.66; 49.1% female; 28.3% Hispanic/Latino/x, 58.5% White) were drawn from the Arizona Twin Project, which recruited children from birth records at 12 months of age. Family orientation values were indexed by parent-reported familism, and family orientation behaviors comprised coded measures of children's family orientation and experimenter ratings of caregiver and child behavior. Self-regulation was assessed using multiple task-based assessments of executive function and parent- and teacher-reported effortful control. Net of covariates, higher family orientation behaviors positively predicted nearly all measures of children's self-regulation, and associations were consistent across sex, family socioeconomic status, and race/ethnicity. There was no evidence that family orientation values nor behaviors moderated the heritability of children's self-regulation. This study highlights the complex nature of cultural variation within the family and its importance for children's self-regulatory abilities. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The Interdependent Nature of Mother's and Children's Temperament and Eating Behaviors on Weight.

OBJECTIVES: The family environment is an important contextual factor for parent and child weight within families. Using an Actor-Partner Interdependence Model, the current study examined (1) the effect of child and mother temperament (i.e., negative affectivity, effortful control, and impulsivity) on mother and child weight, (2) the effect of mother eating behaviors on mother and child weight, and (3) how temperament might moderate the relationships between mother eating behaviors and mother and child weight. METHODS: The sample consisted of 220 mother-child dyads with children between 4 and 6 years of age (66.8% classified as low-, 25.9% middle-, and 5.5% high-income). Mothers completed questionnaires on their own temperament and eating behaviors as well as child temperament. Weight measures were assessed in the laboratory for both mother and child. RESULTS: Mother's negative affectivity and impulsivity were negatively related to mother's weight while children's impulsivity was positively related to children's and mother's weight. Mother's eating behaviors were also positively related to mother's weight. The interaction between child impulsivity and mother eating behaviors was significant; the association of mother eating behaviors with mother weight depended on child impulsivity. Specifically, when children had higher impulsivity, mothers had the highest weight. When children had average or lower impulsivity, mother weight was higher with higher endorsement of unhealthy eating behaviors. CONCLUSIONS: Findings suggest that after adjusting for the interdependent nature of temperament traits and weight, child impulsivity is an important factor associated with current weight for both mothers and children. Results also provide important implications for the impact children can have on their mothers.

The role of early intervention for adolescent mental health and polydrug use: Cascading mediation through childhood growth in the general psychopathology (p) factor.

This study is a secondary data analysis that extends knowledge about the effects of the early childhood Family Check-Up (FCU) intervention to trajectories of general psychopathology problems (p factor) across early and middle childhood, and effects on adolescent psychopathology and polydrug use. The Early Steps Multisite study (ClinicalTrials.gov Identifier NCT00538252) is a randomized controlled trial of the FCU and consists of a large, racially and ethnically diverse sample of children who grew up in low-income households in Pittsburgh, Pennsylvania; Eugene, Oregon; and Charlottesville, Virginia (n = 731; 49% female; 27.6% African American, 46.7% European American, 13.3% Hispanic/Latinx). To represent a comorbid presentation of internalizing and externalizing problems, we fit a bifactor model that included a general psychopathology (p) factor at eight ages in early childhood (ages 2-4), middle childhood (ages 7.5-10.5), and adolescence (age 14). Latent growth curve modeling was conducted to examine trajectories of the p factor across ages within the developmental periods of early and middle childhood. The effects of FCU on the reductions in growth in the childhood p factor had cascading effects on adolescent p factor (i.e., within-domain effect) and polydrug use (i.e., across-domain effect). Findings underscore the utility of the early FCU in preventing a host of maladaptive adolescent outcomes across diverse settings and populations. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Family processes and structure: Longitudinal influences on adolescent disruptive and internalizing behaviors.

Objective: The present study revisits the assumption in American culture, based in "family privilege," that children fare better in two-parent households by longitudinally examining associations between family structure, process, and adolescent behavior. Background: Societal assumptions and cross-sectional research suggest that there is a difference in child adjustment across varying family structures. Relatedly, the family process literature emphasizes the importance of parent-child relationship quality in addition to family structure on child adjustment. Method: We utilized a longitudinal, prospective design that assessed family structures on nine occasions covering a 12-year period beginning when the target child was 2 years of age for a large (N = 714), ethnically and racially diverse sample of low-income families. We examined the relation between self-reported, teacher-reported, and primary caregiver-reported adolescent disruptive and internalizing problem behavior across family structures and parent-child relationship quality. Results: Across seven identified family structures, adolescent behavior did not differ after accounting for middle-childhood adjustment and relevant contextual factors. However, consistent with family process models of child adjustment, positive parent-child relationship quality predicted lower rates of adolescent maladaptive behavior. Conclusion: These findings serve to combat stigma related to family structures that deviate from married parents raising their children and highlight the need for interventions designed to foster positive parent-child relationships. Implications: Policy makers and practitioners should aim to support efforts to foster positive parent-child relationships across types of family structures and refrain from promoting or discouraging the formations of specific family structure types.

Are Daily Well-Being and Emotional Reactivity to Stressors Modifiable in Midlife?: Evidence from a Randomized Controlled Trial of an Online Social Intelligence Training Program.

The complex set of challenges that middle-aged adults encounter emphasizes a need for mental health interventions that promote resilience and positive outcomes. The present study evaluated whether an online, self-guided social intelligence training (SIT) program (8 h) improved midlife adults' daily well-being and emotion regulation in the context of their own naturalistic everyday environment. A randomized controlled trial was conducted with 230 midlife adults allocated into either a SIT program or an attentional control (AC) condition that focused on healthy lifestyle education. Intent-to-treat analyses examined two bursts of 14-day daily surveys that participants completed pre- and post-treatment. Multilevel models evaluated pre-to post-treatment changes in mean positive and negative affect, as well as daily emotional reactivity to stressors and responsiveness to uplifts. Compared to the AC group, those in the SIT program reported improvements (i.e., decreases) in mean negative affect, positive emotional reactivity to daily stressors (i.e., smaller decreases in positive affect on stressor days), and negative emotional responsiveness to uplifts (i.e., lower negative affect on days without uplifts). Our discussion considers potential mechanisms underlying these improvements, highlights downstream effects on midlife functioning, and elaborates on how online delivery of the SIT program increases its potential for positive outcomes across adulthood. ClinicalTrials.gov Identifier: NCT03824353.

A Polygenic Risk Score Enhances Risk Prediction for Adolescents' Antisocial Behavior over the Combined Effect of 22 Extra-familial, Familial, and Individual Risk Factors in the Context of the Family Check-Up.

Possessing informative tools to predict who is most at risk for antisocial behavior in adolescence is important to help identify families most in need of early intervention. Polygenic risk scores (PRSs) have been shown to predict antisocial behavior, but it remains unclear whether PRSs provide additional benefit above more conventional tools to early risk detection for antisocial behavior. This study examined the utility of a PRS in predicting adolescents' antisocial behavior after accounting for a broad index of children's contextual and individual risk factors for antisocial behavior. Participants were drawn from a longitudinal family-based prevention study (N = 463; Ncontrol = 224; 48.8% girls; 45.1% White; 30.2% Black; 12.7% Hispanic/Latino, 10.4% biracial; 0.2% Native American). Participants were recruited from US-based Women, Infants, and Children Nutritional Supplement programs. A risk tolerance PRS was created from a genome-wide association study. We created a robust measure capturing additive effects of 22 conventional measures of a risk of antisocial behavior assessed at child age 2 (before intervention). A latent variable capturing antisocial behavior (ages 10.5-16) was created. After accounting for intervention status and the conventional risk index, the risk tolerance PRS predicted independent variance in antisocial behavior. A PRS-by-conventional risk interaction showed that the conventional risk measure only predicted antisocial behavior at high levels of the PRS. Thus, the risk tolerance PRS provides unique predictive information above conventional screening tools and, when combined with them, identified a higher-risk subgroup of children. Integrating PRSs could facilitate risk identification and, ultimately, prevention screening, particularly in settings unable to serve all individuals in need.

Genetic and environmental links between executive functioning and effortful control in middle childhood.

There is a need to understand the components of self-regulation, given its link to nearly every domain of functioning across the life span. This study examined the etiological underpinnings of covariance between measures of executive functioning (EF) and effortful control (EC) in middle childhood. The extent that genetic and environmental factors explain the association between EF and EC is unknown. Families were drawn from a longitudinal twin study (N = 894 twins; Mage = 8.87 years, SD = 1.10; 51.4% female; 46.8% non-Hispanic White, 28% Latino/a/x) and twins completed EF tasks during a home visit (Flanker Task, Continuous Performance Task, and Digit Span Backward) and primary caregivers (93.8% mothers) reported on their twins' EC (Attentional Focusing and Inhibitory Control). Univariate twin models showed additive genetic and nonshared environmental influences on the Flanker Task, Continuous Performance Task, Digit Span Backward, and parent-reported Inhibitory Control, and dominant genetic influences were implicated in parent-reported Attentional Focusing. Bivariate twin models revealed that additive genetic influences explained the small covariance between EF and EC. Executive attention could explain the genetic covariance between measures of EF and EC. This study suggests that EF and EC tap into the same underlying self-regulation construct, with weak correlations between constructs being attributed to measurement, rather than conceptual, differences. Elucidating the overlap between EF and EC can bring researchers closer to understanding how best to foster adaptive self-regulation. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A gene-environment cascade theoretical framework of developmental psychopathology.

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

Childhood inhibition predicts adolescent social anxiety: Findings from a longitudinal twin study.

An enduring issue in the study of mental health is identifying developmental processes that explain how childhood characteristics progress to maladaptive forms. We examine the role that behavioral inhibition (BI) has on social anxiety (SA) during adolescence in 868 families of twins assessed at ages 8, 13, and 15 years. Multimodal assessments of BI and SA were completed at each phase, with additional measures (e.g., parenting stress) for parents and twins. Analyses were conducted in several steps: first, we used a cross-lagged panel model to demonstrate bidirectional paths between BI and SA; second a biometric Cholesky decomposition showed that both genetic and environmental influences on childhood BI also affect adolescent SA; next, multilevel phenotypic models tested moderation effects between BI and SA. We tested seven potential moderators of the BI to SA prediction in individual models and included only those that emerged as significant in a final conditional model examining predictors of SA. Though several main effects emerged as significant, only parenting stress had a significant interaction with BI to predict SA, highlighting the importance of environmental moderators in models examining temperamental effects on later psychological symptoms. This comprehensive assessment continues to build the prototype for such developmental psychopathology models.

Developmental genetic effects on externalizing behavior and alcohol use: Examination across two longitudinal samples.

Externalizing behavior in early adolescence is associated with alcohol use in adolescence and early adulthood and these behaviors often emerge as part of a developmental sequence. This pattern can be the result of heterotypic continuity, in which different behaviors emerge over time based on an underlying shared etiology. In particular, there is largely a shared genetic etiology underlying externalizing and substance use behaviors. We examined whether polygenic risk for alcohol use disorder predicted (1) externalizing behavior in early adolescence and alcohol use in adolescence in the Early Steps Multisite sample and (2) externalizing behavior in adolescence and alcohol use in early adulthood in the Project Alliance 1 (PAL1) sample. We examined associations separately for African Americans and European Americans. When examining European Americans in the Early Steps sample, greater polygenic risk was associated with externalizing behavior in early adolescence. In European Americans in PAL1, we found greater polygenic risk was associated with alcohol use in early adulthood. Effects were largely absent in African Americans in both samples. Results imply that genetic predisposition for alcohol use disorder may increase risk for externalizing and alcohol use as these behaviors emerge developmentally.

Does stress predict the development of internalizing symptoms in middle childhood? An examination of additive, mediated, and moderated effects of early family stress, daily interpersonal stress, and physiological stress.

Early life stress, daily life experiences, and the stress responsive hypothalamic-pituitary-adrenal (HPA) axis have each been examined as predictors of the development of psychopathology. Rarely have researchers attempted to understand the covariation or interaction among these stress domains using a longitudinal design in the prediction of symptoms of internalizing psychopathology, particularly during childhood. This study examined early family stress, daily interpersonal stress, indicators of diurnal cortisol, and internalizing symptoms in a racially/ethnically and socioeconomically diverse sample of twins (N = 970 children; Mage at outcome = 9.73; 52% female; 23.7% Hispanic/Latino, 58.8% White; 30% below middle class; Lemery-Chalfant et al., 2019). An additive model of stress, a stress mediation model, and a stress sensitization framework model each delineated potential pathways linking stress and internalizing symptoms. Supporting additive pathways, multilevel models showed that all 3 stress indicators uniquely predicted internalizing symptoms. There was a significant indirect path from early family stress to 9 year internalizing symptoms through interpersonal stress, supporting stress mediation. Family stress moderated the association between interpersonal stress and internalizing symptoms, though not in the direction that would support stress sensitization. Child stress, including daily interpersonal stress and HPA axis activity, and internalizing symptoms are prevalent and family stress is a significant precursor to child internalizing symptoms across child development. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Early Life Socioeconomic Differences in Associations between Childhood Sleep and Academic Performance.

Poor sleep can negatively impact children's academic performance. However, it is unknown whether early-life socioeconomic status (SES) moderates later sleep and academics. We tested associations between actigraphy-based sleep duration and midpoint time, and parent-reported sleep problems with objective and subjective measures of academic performance. We also examined whether relations varied by early and concurrent SES. Children (n=707; 52% female; M age=8.44 years; 28.7% Hispanic/Latinx; 29.7% at/below poverty line) were assessed at 12 months for SES and eight years for SES, sleep, and academics. There were no main effects of sleep on academics. More sleep problems predicted lower Applied Problems performance for low SES children (b=-.73, p<.05) and better performance for high SES children (b=.69, p<.05). For high SES children, greater sleep problems (b=-.11, p<.05) and longer sleep duration (b=-.11, p<.05) predicted lower academic achievement. However, most associations were consistent across SES, illustrating the complex interplay between sleep, academic outcomes, and SES.

The onset of pubertal development and actigraphy-assessed sleep during middle childhood: Racial, gender, and genetic effects.

OBJECTIVE: This study (1) examined pubertal development in relation to actigraphy-assessed sleep in twin children, and tested whether associations differed by child race and gender, (2) modeled genetic and environmental influences on pubertal development and sleep indicators, and (3) examined genetic and environmental influences on the covariation of puberty and sleep. DESIGN: The classic twin design was used to examine genetic and environmental contributions to puberty and sleep and their associations. SETTING: Data were collected from community-dwelling urban and rural families of twins in the southwestern U.S. PARTICIPANTS: The racially and socioeconomically diverse sample included 596 twin children (Mage = 8.41, SD = 0.69; 51.7% female; 66.3% white; 33.7% Hispanic; 170 monozygotic, 236 same-sex dizygotic, 188 opposite-sex dizygotic). MEASUREMENTS: Pubertal development was assessed via parent report. Children wore actigraph watches for 7 nights (M = 6.81, SD = 0.67) to capture sleep duration, efficiency, midpoint, onset latency, and duration variability. RESULTS: In contrast to extant literature with older youth, more advanced pubertal development was associated with longer sleep durations in Hispanic and white girls and higher sleep efficiency in white girls, though Hispanic girls demonstrated later sleep midpoints. Pubertal development was moderately heritable and there was a genetic influence on the covariance between puberty and sleep indicators. CONCLUSIONS: This was the first study to examine the genetic and environmental influences on the covariation between puberty and sleep, and found genetic underpinnings between pubertal development and actigraphy-assessed sleep duration and efficiency, though sleep and puberty were almost entirely independent in twins at this age.

Indirect Associations between Middle-Childhood Externalizing Behaviors and Adolescent Substance Use through Late-Childhood Exposure to Violence.

Longitudinal research to understand individual risk factors in childhood associated with exposure to violence and substance use is needed to inform prevention efforts. The present study tested indirect associations between age 8.5 externalizing behaviors and age 16 substance use through age 9.5 violence victimization and witnessing. Participants were 650 racially diverse (48.6% European American, 28.1% African American, 13.3% multiracial, and 10.0% other), predominantly socioeconomically disadvantaged youth (49% female). Externalizing behaviors were associated with higher levels of violence victimization and witnessing. The indirect path from externalizing behaviors to substance use was significant through victimization but not witnessing violence. Interventions aimed at reducing early externalizing behaviors may reduce risk for violence victimization, which may, in turn, reduce risk for adolescent substance use.