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.

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).

Unique and interactive effects of threat and deprivation on latent trait cortisol among emerging adults.

Though considerable work supports the Dimensional Model of Adversity and Psychopathology, prior research has not tested whether the dimensions-threat (e.g., abuse) and deprivation (e.g., neglect)-are uniquely related to salivary trait indicators of hypothalamic pituitary adrenal (HPA) axis activity. We examined the unique and interactive effects of threat and deprivation on latent trait cortisol (LTC)-and whether these effects were modified by co-occurring adversities. Emerging adults (n = 90; Mage = 19.36 years; 99.88% cisgender women) provided salivary cortisol samples four times a day (waking, 30 min and 45 min postwaking, bedtime) over three 3-day measurement waves over 13 weeks. Contextual life stress interviews assessed early adversity. Though the effects varied according to the conceptualization of early adversity, overall, threat-but not deprivation, nor other co-occurring adversities-was uniquely associated with the across-wave LTC. Specifically, the incidence and frequency of threat were each negatively related to the across-wave LTC. Threat severity was also associated with the across-wave LTC, but only among those with no deprivation. Finally, the effects of threat were modified by other co-occurring adversities. Findings suggest that threat has unique implications for individual differences in HPA axis activity among emerging adults, and that co-occurring adversities modify such effects.

Contextualizing Bicultural Competence Across Youths' Adaptation From High School to College: Prospective Associations With Mental Health and Substance Use.

Bicultural competence, the ability to navigate bicultural demands, is a salient developmental competency for youth of color linked with positive adjustment. This study investigated how discrimination experiences informed developmental trajectories of behavioral and affective bicultural competence across youth's adaptation from high school to college, and how these biculturalism trajectories predicted later adjustment (i.e., internalizing symptoms and binge drinking). Data were collected between 2016 through 2020 and included 206 U.S. Latino youth (Mage=17.59, 64% female, 85% Mexican origin, 11% first and 62% second generation immigrants). Linear latent growth analyses revealed that youth who experienced greater time-varying discrimination demonstrated lower concurrent behavioral and affective bicultural competence. Higher behavioral bicultural competence intercepts were associated with fewer internalizing symptoms in the third college year. No other significant associations emerged for internalizing symptoms or binge drinking. These findings have implications for mental health equity among Latino youth during a critical period of psychopathology onset.

Within-person reciprocal links between stress, sleep, and depressive symptoms across Latino/a adolescents' transition to and through college.

Evidence suggests bidirectional relations between stress, sleep, and depressive symptoms in adolescence and young adulthood. Less research has disaggregated within- and between-person variance in these associations over time or within Latino/a college students. This study examined longitudinal, within-person reciprocal relations between stress, sleep, and depressive symptoms among 181 Latino/a adolescents (M age = 18.10; SD = 0.41, 35% male) transitioning to college. Participants were assessed in their senior year of high school and annually until their fourth year of college. A random intercept cross-lagged panel model (RI-CLPM) was used to parse out within- and between-person sources of variance. Results indicated overall (between-person) relations among depressive symptoms and school/college stress and sleep problems. There were reciprocal within-person links between stress and sleep problems across the first two years of college. Within-person increases in depressive symptoms during the second year of college predicted more stress than usual in the third year, which predicted increased depressive symptoms in the fourth year. More sleep problems than usual in the third year of college predicted higher stress in the fourth year. Findings provide evidence for within-person cross-lagged relations among various domains of adjustment during college and may inform future prevention efforts for incoming Latino/a college students targeting mental health and sleep problems.

Latent Profiles of Sleep Patterns in Early Adolescence: Associations With Behavioral Health Risk.

PURPOSE: The present study characterized sleep profiles in a national longitudinal sample of early adolescents and examined whether profiles predicted later behavioral problems. METHODS: Three waves of data (2016-2021) were obtained from the Adolescent Behavior and Cognitive Development study, including 3,326 participants with both weekday and weekend sleep data measured by Fitbit wearables (age range 10.58-13.67 years; 49.3% female). Latent profile analysis was utilized to identify sleep profiles using multiple sleep indicators (duration, latency, efficiency, wake minutes, wake counts, and midpoint). We then explored whether demographic predictors predicted profile membership and tested the latent sleep profiles' predictive utility of internalizing and externalizing symptoms. RESULTS: Four profiles were identified: average sleep (40.39%), high duration & high wakefulness (28.58%), high efficiency, low duration &low wakefulness (16.86%), and low duration & low efficiency (14.17%). Participants with older age, males, higher body mass index, and advanced pubertal status were more likely to be classified in the low duration & low efficiency profile than the average group. Participants with lower income, minority identification, older age, and higher body mass index were more likely to be classified in the high efficiency, low duration &low wakefulness than the average group. Participants with lower parental education and males were more likely to be in the high sleep duration & high wakefulness than the average group. The low duration & low efficiency group had the highest attention problems, social problems, and rule-breaking behaviors. DISCUSSION: Our findings highlight unique sleep patterns in early adolescence and their prospective links with internalizing and externalizing problems.

The Influence of Pubertal Development on Early Adolescent Sleep and Changes in Family Functioning.

Pubertal development has been separately linked to adolescents' sleep problems and larger family functioning, but research connecting these inter-related processes remains sparse. This study aimed to examine how pubertal status and tempo were related to early adolescents' sleep and their family functioning. Using longitudinal data from the Adolescent Brain and Cognitive Development study, the study's sample (N = 4682) was 49.2% female, was an average of 9.94 years old at baseline, and was 60.1% white. Analyses in the current study modeled the indirect associations between pubertal change and changes in family conflict via adolescent sleep duration and variability of duration. The results suggested that pubertal status and tempo predicted shorter adolescent sleep durations and greater variability in those durations, which predicted residual increases in family conflict. The findings highlight the role of adolescents' pubertal changes in their sleep and how such changes can negatively affect family functioning.

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.

Associations between COVID-19 sleep patterns, depressive symptoms, loneliness, and academic engagement: a latent profile analysis.

Background: The COVID-19 pandemic has had important implications for college students' socioemotional and academic well-being. Sleep problems were common during this time, which may have further impacted well-being. Methods: Five hundred and fifty-two college students (Mage = 19.81; 58% female; 42% White) completed a survey in Fall 2021 reflecting on behaviors/emotions (sleep, depressive symptoms, loneliness, academic engagement) experienced during the first peak of COVID-19 and over the past month. Latent profile analysis was conducted to identify subgroups of sleepers during peak-COVID in relation to well-being during and after the initial peak. Results: Four sleep profiles were identified: Optimal (49%), High Latency/Medicated (23%), Average/Fair (16%), Low-Duration (12%). During peak-COVID, depression and loneliness were highest in High Latency/Medicated and Low-Duration subgroups; academic engagement was highest for Optimal sleepers. Following peak-COVID, academic engagement was highest for Average/Fair sleepers. Conclusions: Findings highlight heterogeneity in students' sleep patterns during the initial peak of COVID-19 and their relation to well-being during and post-peak-pandemic.

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).

Stress and diurnal cortisol among Latino/a college students: A multi-risk model approach.

The transition to college is a time of increased opportunity and stress spanning multiple domains. Adolescents who encounter significant stress during this transition may be vulnerable to adverse outcomes due to a "wear and tear" of the hypothalamic pituitary adrenal (HPA) axis. Latino/a students may be particularly at-risk for heightened stress exposure due to experiences of both minority-specific and general life stress. Despite this, little is known regarding the cumulative impact of multiple stressors on Latino/a students' HPA axis functioning. The present study employed a "multi-risk model" approach to examine additive, common, and cumulative effects of multiple stress forms (general, academic, social, financial, bicultural, ethnic/racial discrimination) on diurnal cortisol in a sample of first-year Latino/a college students (N = 196; 64.4% female; Mage = 18.95). Results indicated that no stress forms were additively associated with the cortisol awakening response (CAR), but general stress was associated with a flatter diurnal cortisol slope (DCS) and bicultural stress was linked with a steeper DCS. A college stress latent factor was associated with a lower CAR, whereas a latent factor of discrimination was not associated with diurnal cortisol. Cumulative risk was linked with a lower CAR. Findings highlight the physiological correlates of various stressors experienced by Latino/a college students.

Ethnic-Racial Identity Developmental Trajectories Across the Transition to College.

There is limited longitudinal research examining multiple ethnic-racial identity (ERI) components from adolescence into young adulthood. The current study modeled Latino adolescents' ERI trajectories across the college transition (N = 206; Mage = 18.10 years, SD = 0.41; 65.0% female). Longitudinal data from a survey administered on five occasions across 3 years were analyzed using multilevel growth modeling. Prior to college, Latino heritage culture orientation was positively associated with ERI exploration and resolution. ERI exploration increased over time. ERI resolution was high with no average change; Latino heritage culture orientation predicted variability in resolution over time. Before college, male-identifying youth reported higher ERI public regard from teachers/professors compared to female-identifying youth. Public regard increased to a greater extent for female compared to male adolescents. The findings join evidence for lifespan and intersectional models of ERI development.

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).

Family dynamics and adjustment across Latino/a students' transition to college: Disentangling within- and between-person reciprocal associations.

Latino/a adolescents are increasingly represented in higher education. Whereas previous work suggests that positive aspects of the family can promote adjustment during the college transition, less is known regarding the longitudinal, reciprocal nature of these associations. The current study examined changes in parenting, family dynamics, and adjustment across the transition from high school to college among 207 Latino/a young adults (Mage = 18.10; 65.0% female identifying) in the Southwestern United States and investigated within- and between-person reciprocal relations using standard and random-intercept cross-lagged panel models. Participants self-reported on parental support, parental monitoring, family communication, depressive symptoms, and alcohol use during their senior year of high school (Time 1; spring/summer 2017), first semester of college (Time 2; fall 2017), and second semester of college (Time 3; spring/summer 2018). Parental support, family communication, depressive symptoms, and alcohol use increased across the initial transition from high school to college, whereas parental monitoring decreased across time. Reciprocal effects were largely between-person driven. Family communication in high school was concurrently and prospectively related to fewer depressive symptoms. Higher parental monitoring during the first semester of college was related to less alcohol use within and across semesters. In addition, students who experienced within-person increases in depressive symptoms during the first semester of college perceived less parental support than usual the next semester. Study findings point to the importance of developmental timing and further highlight the role that family plays during Latino/a students' transition to college. Implications for family-based prevention efforts are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Individual differences in latent trait cortisol (LTC): Implications for the onset and course of future depressive symptoms.

Research suggests that various indicators of hypothalamic pituitary adrenal (HPA) axis activity prospectively predict depression, but few studies have evaluated whether trait indicators of HPA axis activity are related to depression. Further, no prior study has examined links between trait cortisol and psychopathology using a trait indicator that captures HPA axis activity over multiple time points. Here we examined whether we could construct an across-wave latent trait cortisol (LTC) factor using cortisol samples collected over 13 weeks, and whether the across-wave LTC prospectively predicted new depressive symptom onsets and symptom duration. Emerging adults (n = 85; M age = 19.37 years) provided salivary cortisol samples four times a day (waking, 30 min and 45 min post-waking and bedtime) over three 3-day measurement waves separated by 6 weeks. Diagnostic interviews at 3 timepoints (baseline, 1- and 2.5 years post-baseline) assessed lifetime and current depressive symptoms. Results indicated that the across-wave LTC predicted new onsets of depressive symptoms and longer symptom duration. Follow-up tests revealed that the link between the across-wave LTC and new onsets was not significant after adjusting for past depressive symptoms. These findings suggest that an indicator of individual differences in HPA axis regulation has implications for depressive symptom onsets and course.

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).

Bicultural competence and academic adjustment across Latino youth adaptation from high school to college.

This study investigated the association between bicultural competence and academic adjustment (i.e., engagement, efficacy, achievement) among 193 Latino youth (65.3% female; 89.1% U.S.-born) followed from their senior high school year (Mage  = 17.58 years, SD = 0.53) to their fifth college semester (2016-2019). Latent growth analyses revealed that youth's overall bicultural competence trajectory was moderately high and stable across this period. Youth who maintained or increased bicultural competence levels over time (slopes) demonstrated greater self-efficacy. Youth with greater high school bicultural competence (intercepts) demonstrated higher engagement but lower achievement. No other associations emerged. This study highlights that the promoting influence of bicultural competence may not extend to all indicators of academic adjustment but may depend upon the contexts and demands they navigate.

Reciprocal associations of perceived discrimination, internalizing symptoms, and academic achievement in Latino students across the college transition.

OBJECTIVE: Despite growing evidence that perceived discrimination negatively impacts underrepresented ethnic-racial college students, there is a lack of longitudinal studies with multiple sources of discrimination as Latinos transition from high school (HS) to college. This study examined changes in peer, adult, and everyday discrimination across the college transition and tested concurrent, prospective, and reciprocal associations between these sources of discrimination, internalizing symptoms, and grade point average (GPA). METHOD: Latino adolescents (N = 209; Mage at Time 1 = 18.10; 64.4% female; 85.1% Mexican descent) reported on discrimination experiences and internalizing symptoms during their final year of high school and first college semester. Participants' GPA was obtained from institutional records. Longitudinal data were analyzed using cross-lagged panel models. RESULTS: Adult discrimination remained stable while peer and everyday discrimination decreased from high school to college. All sources of discrimination were concurrently associated with internalizing symptoms, but not GPA, in high school and college. There were positive bidirectional associations between everyday discrimination and internalizing symptoms across the college transition. Adult discrimination during high school predicted increased discrimination from adults and peers in college. First-generation college students reported higher everyday and peer discrimination in college. CONCLUSIONS: Latino students' experiences of everyday and ethnic-racial discrimination in school may be more closely tied to psychological rather than academic adjustment in the first semester of college. First-generation college students and those who experienced higher adult discrimination or internalizing symptoms in high school appear to be more susceptible to increased perceptions of discrimination during the college transition. (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.