Sibling Facilitation Mediates the Association Between Older and Younger Sibling Alcohol Use in Late Adolescence

Sibling influences on adolescent alcohol use during the spring 2020 COVID-19 pandemic shutdown

OBJECTIVE

To examine the bidirectional associations between adolescent siblings' alcohol use before and during the onset of the COVID-19 pandemic in Spring 2020 and whether youths' stress about missed social connections (i.e., social disruption stress) moderated these associations.

METHOD

The sample consisted of 682 families (2,046 participants) with two adolescent siblings (older siblings: Mage = 15.67 years, 51% female; younger siblings: Mage = 13.14 years, 48% female) and one parent (Mage = 45.15 years; 85% female) from five Midwestern U.S. states. Siblings reported on their own drinking and social disruption stress before and during the onset of the pandemic via online surveys.

RESULTS

Accounting for younger siblings' earlier drinking and other confounders, older siblings' prepandemic drinking predicted a greater likelihood of younger siblings' drinking during the Spring 2020 pandemic shutdown. This association was not moderated by younger siblings' social disruption stress. The association between younger siblings' prepandemic drinking and older siblings' drinking during the shutdown was moderated by older siblings' social disruption stress. Specifically, younger siblings' earlier drinking was more strongly related to older siblings' drinking during the shutdown if older siblings reported more social disruption stress.

CONCLUSIONS

Siblings are important socialization agents of alcohol use during adolescence. Sibling interventions may be particularly salient during times of stress and isolation when youths' social interactions with peers may be limited. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Associations between older siblings' substance use and younger siblings' substance use intentions: Indirect effects via substance use expectations

OBJECTIVE

We examined the direct and indirect effects of older siblings' substance use behaviors (i.e., cannabis and e-cigarettes) on younger siblings' later substance use intentions via their substance use expectations.

MATERIAL AND METHODS

Data were collected from 682 families (N = 2,046) with two adolescent siblings (older siblings: M age = 15.67 years, 51% female; younger siblings: M age = 13.14 years, 48% female) and one parent (M age = 45.15 years; 85% female). Participants completed annual online surveys at two occasions. Older siblings reported on their cannabis and e-cigarette use frequencies (Time 1) and younger siblings reported on their substance use expectations (Time 1) and intentions (Time 1 and 2); parents reported on adolescents' sociodemographic characteristics and their own substance use (Time 2).

RESULTS

Structural equation modeling results suggested that older siblings' cannabis and e-cigarette use was indirectly related to younger siblings' later intentions to use these substances through their positive expectations about substances, after accounting for younger siblings' earlier intentions to use substances and control variables including parents' and friends' use. There were no significant direct relations between older siblings' cannabis or e-cigarette use and younger siblings' intentions to use them.

CONCLUSIONS

Findings indicate that older siblings are critical and unique socialization agents of younger siblings' expectations and intentions to use substances. Intervention and prevention programs that target adolescents' substance use should consider the ways in which siblings shape each other's substance use.

Birth order and health events attributable to alcohol and narcotics in midlife: A 25-year follow-up of a national Swedish birth cohort and their siblings

Higher birth order is associated with increased risks of adverse health outcomes attributable to alcohol or narcotics in adolescence, but it remains unclear whether these observed birth order effects are also present in midlife. Drawing on a national Swedish cohort born in 1953 and their siblings, we estimate associations between birth order and alcohol- or narcotics-attributable hospitalization or death with a 25-year follow-up to assess whether birth order differences are observed during this life course period. Health events attributable to alcohol or narcotics use were identified using the Swedish National Patient and Cause of Death registers, respectively. We apply Cox proportional hazards models to estimate average birth order differences in hazards for alcohol- or narcotics-attributable hospitalization or death between ages 30 and 55. We estimate birth order differences between families, and use two fixed-effects approaches to estimate birth order differences within families and within families of the same type. Bivariate results indicate increased hazards for both outcomes with higher birth order; however, these results are no longer observed after adjustment for familial background characteristics in all models. Our results thereby show limited evidence for birth order differences in midlife. This study highlights that shared factors within the family of origin may be stronger predictors of adverse health outcomes attributable to substance use among siblings during this life course period. Future research should disentangle the contributions of the social environment within the family of origin for adverse health outcomes attributable to alcohol or narcotics among siblings.

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We estimate birth order differences for alcohol or narcotics use outcomes between ages 30-55.

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Birth order differences are not observed for alcohol- or narcotics-attributable events in midlife.

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Family background characteristics may be stronger predictors of these outcomes.

Building causal knowledge in behavior genetics

Behavior genetics is a controversial science. For decades, scholars have sought to understand the role of heredity in human behavior and life-course outcomes. Recently, technological advances and the rapid expansion of genomic databases have facilitated the discovery of genes associated with human phenotypes such as educational attainment and substance use disorders. To maximize the potential of this flourishing science, and to minimize potential harms, careful analysis of what it would mean for genes to be causes of human behavior is needed. In this paper, we advance a framework for identifying instances of genetic causes, interpreting those causal relationships, and applying them to advance causal knowledge more generally in the social sciences. Central to thinking about genes as causes is counterfactual reasoning, the cornerstone of causal thinking in statistics, medicine, and philosophy. We argue that within-family genetic effects represent the product of a counterfactual comparison in the same way as average treatment effects (ATEs) from randomized controlled trials (RCTs). Both ATEs from RCTs and within-family genetic effects are shallow causes: They operate within intricate causal systems (non-unitary), produce heterogeneous effects across individuals (non-uniform), and are not mechanistically informative (non-explanatory). Despite these limitations, shallow causal knowledge can be used to improve understanding of the etiology of human behavior and to explore sources of heterogeneity and fade-out in treatment effects.

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

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

Trajectories of depressive symptoms from adolescence to emerging adulthood: The influence of parents, peers, and siblings

The primary purpose of this study was to examine whether social relationship factors are associated with trajectories of depressive symptoms from adolescence into emerging adulthood. Specifically, adolescent-parent communication with mothers and fathers, peer support, and sibling warmth and hostility were examined in relation to depressive symptoms for girls and boys. Adolescents (N = 372; M_age = 16.09; SD = .69; 55% female) from the Mid-Atlantic United States completed surveys in the spring of 2007, 2008, and 2009 and again in the fall of 2014 when they were emerging adults. Growth curve modeling results suggested that communication with mothers and fathers and peer support predicted lower levels of depressive symptoms in adolescence for girls. For boys, peer support predicted lower whereas sibling hostility predicted higher levels of depressive symptoms in adolescence. Further, adolescent-mother communication for girls and adolescent-father communication for boys predicted the decline in depressive symptoms into emerging adulthood. Both sibling warmth and hostility for girls, whereas only sibling hostility for boys, predicted less steep declines in depressive symptoms over time. Findings draw attention to differences in experiences with depressive symptoms by sex and the importance of social relationship factors in the lives of adolescents and emerging adults. Implications for intervention and prevention are discussed. (PsycINFO Database Record

Alcohol Metabolizing Polygenic Risk for Alcohol Consumption in European American College Students

OBJECTIVE

Evidence suggests that the nature and magnitude of some genetic effects on alcohol use vary by age. We tested for moderation in the effect of an alcohol metabolizing polygenic score by time across the college years.

METHOD

Participants (total n = 2,214) were drawn from three cohorts of undergraduate college students, who were assessed annually for up to 4 years starting in their freshman year. Polygenic risk scores (PRSs) were calculated from genes involved in the metabolism of alcohol, as many of these markers are among the best replicated in association studies examining alcohol use phenotypes. Linear mixed effects models were fit by maximum likelihood to test the main effects of time and the PRS on alcohol consumption, as well as moderation of the PRS effect on alcohol consumption by time.

RESULTS

In the main effects model, the fixed effects for time and the PRS were positively associated with alcohol consumption. The interaction term testing moderation of the PRS effect by time reached statistical significance and remained statistically significant after other relevant interaction effects were controlled for. The main effect of the PRS accounted for 0.2% of the variance in alcohol consumption, whereas the interaction of PRS effect and time accounted for 0.05%.

CONCLUSIONS

Alcohol metabolizing genetic effects on alcohol use appear to be more influential in later years of college than in earlier years. Shifting environmental contexts, such as increased access to alcohol as individuals approach the legal age to purchase alcohol, may account for this association.

Parents' Social Comparisons of Siblings and Youth Problem Behavior: A Moderated Mediation Model

Parents compare their children to one another; those comparisons may have implications for the way mothers and fathers treat their children, as well as their children's behavior. Data were collected annually for three years with parents, firstborns, and secondborns from 385 families (Time 1 age: firstborns, 15.71, SD = 1.07, 52% female; secondborns, 13.18, SD = 1.29, 50% female). Parents' beliefs that one child was better behaved predicted differences in siblings' reports of parent-child conflict. Additionally, for siblings close in age, mothers' comparisons at Time 1 predicted youth's problem behavior at Time 3 through siblings' differential conflict with mothers. The results support and extend tenets from Social Comparison and Expectancy Value theories in regards to social comparison within families.

Sibling Influences on Risky Behaviors from Adolescence to Young Adulthood: Vertical Socialization or Bidirectional Effects?

This study built on research on sibling influences to assess potential bidirectional effects of older and younger siblings' risky behaviors on one another's risky behaviors; our longitudinal design allowed us to test these effects when siblings were at about the same chronological age, at different points in time. We also tested whether the strength and/or direction of effects of siblings' risky behaviors changed from middle adolescence to young adulthood. Reports of risky behaviors (i.e., deviant behaviors and excessive alcohol use) were provided by firstborn and secondborn siblings from up to 201 families on five occasions spanning 10 years. In general, accounting for known covariates, multilevel models revealed bidirectional sibling effects and some evidence that secondborns' risky behaviors were stronger and more consistent predictors of firstborns' behaviors than the reverse. Sibling influence generally declined with age and sibling effects were not moderated by gender constellation. Findings indicate that both older and younger siblings are important socializers of risk behaviors across adolescence and continue to shape each other's alcohol use into early adulthood.

Mothers', fathers', and siblings' perceptions of parents' differential treatment of siblings: Links with family relationship qualities

A family systems perspective directs attention to the potentially different experiences and perspectives of family members. This study examined parents' differential treatment (PDT) of siblings, discrepancies between parent and youth reports of PDT, and their links with relationships between adolescents and their mothers and fathers across three years. Participants were first- (Time 1 M age = 15.71, SD = 1.07) and secondborn (Time 1 M age = 13.18, SD = 1.29) siblings from 381, predominately white, working and middle class families. Analyses revealed that siblings' perceptions of being favored predicted less conflict with and greater warmth from both mothers and fathers, primarily for secondborn adolescents. Larger discrepancies between maternal and youth reports of differential affection were linked to more maternal conflict and less warmth for firstborns. These findings may suggest a hierarchy within families: parents may serve as referents for firstborns and firstborns as referents for secondborns.

The Developmental Unfolding of Sibling Influences on Alcohol Use over Time

Research has long demonstrated that siblings are similar in their alcohol use, however much of this work relies on cross-sectional samples or samples of adolescents alone and/or exclusive focus on older siblings' impact on younger siblings. Using a three time-point design from early adolescence to early adulthood (M ages = 14.9, 18.3, and 22.4 years, respectively; 55% female; 54% European ancestry, 38% Asian ancestry), we evaluated the prospective older and younger sibling influences on alcohol use across time (N = 613 sibling pairs; 35% sisters, 26% brothers, 39% mixed-gender; average age difference = 2.34 years; 34% full-biological siblings, 46% genetically-unrelated adopted siblings, 20% pairs where one child was the biological offspring of parents and the other was adopted). The results from both the traditional and random-intercept cross-lagged panel analyses showed that older siblings' alcohol use predicted younger siblings' alcohol use across each developmental transition and across a variety of sibling contexts (e.g., gender composition, age difference, genetic relatedness). On the other hand, younger siblings' alcohol use only predicted older siblings' alcohol use when siblings were close in age (1.5 years or less) and under conditions of high sibling companionship. These results add to a body of literature illustrating how both older and younger siblings are important socializing agents of adolescent and early adult alcohol use. Assessing or co-treating siblings for alcohol problems may be an important add-on to existing adolescent and early adult alcohol prevention and intervention programs.

Parental supply of alcohol and alcohol consumption in adolescence: prospective cohort study

BACKGROUND

Parents are a major supplier of alcohol to adolescents, yet there is limited research examining the impact of this on adolescent alcohol use. This study investigates associations between parental supply of alcohol, supply from other sources, and adolescent drinking, adjusting for child, parent, family and peer variables.

METHOD

A cohort of 1927 adolescents was surveyed annually from 2010 to 2014. Measures include: consumption of whole drinks; binge drinking (>4 standard drinks on any occasion); parental supply of alcohol; supply from other sources; child, parent, family and peer covariates.

RESULTS

After adjustment, adolescents supplied alcohol by parents had higher odds of drinking whole beverages [odds ratio (OR) 1.80, 95% confidence interval (CI) 1.33-2.45] than those not supplied by parents. However, parental supply was not associated with bingeing, and those supplied alcohol by parents typically consumed fewer drinks per occasion (incidence rate ratio 0.86, 95% CI 0.77-0.96) than adolescents supplied only from other sources. Adolescents obtaining alcohol from non-parental sources had increased odds of drinking whole beverages (OR 2.53, 95% CI 1.86-3.45) and bingeing (OR 3.51, 95% CI 2.53-4.87).

CONCLUSIONS

Parental supply of alcohol to adolescents was associated with increased risk of drinking, but not bingeing. These parentally-supplied children also consumed fewer drinks on a typical drinking occasion. Adolescents supplied alcohol from non-parental sources had greater odds of drinking and bingeing. Further follow-up is necessary to determine whether these patterns continue, and to examine alcohol-related harm trajectories. Parents should be advised that supply of alcohol may increase children's drinking.

Contextual influences on early drinking: Characteristics of drinking and nondrinking days

Research characterizing the adolescent drinking context is limited, often relies on samples of current drinkers reporting on recent/last or typical drinking experiences, and provides little information about the context of very early use. The present study uses repeated monthly assessments to describe the context of drinking days and matched nondrinking days to determine the unique risk associated with different drinking-related characteristics. Additionally, we used latent class analysis to empirically identify key configurations of drinking-related characteristics and both family- and nonfamily-related environmental characteristics (social context, physical location, source of alcohol). Data included 688 days (344 drinking days, 344 nondrinking days) from 164 middle-school students enrolled in a prospective study on drinking initiation and progression (62% female; 26% non-White, 11% Hispanic). Results supported 4 patterns: (a) heavier drinking occurring in a peer context, lighter drinking occurring in (b) a family context or (c) a peer context, and (d) drinking alcohol obtained at home without permission. Latent classes varied as a function of gender, age, peer norms, and parenting behaviors as well as alcohol type and perceived alcohol availability. Findings indicated that highly endorsed contexts were not necessarily the riskiest ones, and simply targeting an oft-reported source of alcohol, physical location, or social context may not be an effective strategy for reducing underage drinking. Additionally, although greater monitoring and anticipated parent reaction to drinking are typically protective against adolescent drinking, we found they were associated with parent-sanctioned drinking, suggesting the role of parenting practices must be considered in the context of drinking pattern. (PsycINFO Database Record

The role of siblings in adoption outcomes and experiences from adolescence to emerging adulthood

In many families, siblings play important roles in shaping each other's outcomes and experiences across development. In adoptive families, siblings may affect adoptees' feelings about adoption and birth family contact. Among "target adoptees" (i.e., 1 participating adopted individual within adoptive families) with siblings who may have also been adopted or the biological children of the adoptive parents, we examined how adoption experiences and individual adjustment from adolescence into emerging adulthood were associated with sibling relationship dynamics. We present 3 studies using longitudinal, mixed method data within the same overarching sample of adoptive families. Study 1 was a follow-up to Berge et al.'s (2006) study of adolescent adoptees and their adopted siblings with birth family contact; we found evidence of changes in the status of contact collectively experienced by 26 adopted sibling pairs when target adoptees were emerging adults. In Study 2, we found that target adoptees (n = 91) with siblings (adopted or not) who were more involved with target adoptees' birth family contact demonstrated more favorable behavioral outcomes than target adoptees who had uninvolved siblings. Finally in Study 3, for target adoptees with siblings who were also adopted (n = 51), results showed that target adoptees felt more positively about their own adoption when siblings expressed similar positive feelings about individual adoption experiences. Implications of our findings are discussed in terms of the enduring contributions of sibling relationships from childhood into adulthood and the unique ways in which adoptive siblings are important in shaping one another's experiences of adoption.

Social Risk Factors of Black and White Adolescents' Substance Use: The Differential Role of Siblings and Best Friends

Efforts to understand peer influence among adolescents have established the robust relationship between having substance using peers and future substance use. Still, research suggests that peer influence affects different types of adolescents in different ways. Black adolescents may be less susceptible to friends compared to white adolescents and possess stronger family-orientation, suggesting that siblings may affect deviance of Black adolescents whereas friends will have a minimal impact. This study used data from the first two waves of the National Longitudinal Study of Adolescent to Adult Health to evaluate the relative strength of best friend and siblings' influence as risk factors for Black and White adolescents' alcohol and cigarette use. Approximately 182 Black sibling pairs (37 % male) and 657 white sibling pairs (46 % male) that ranged in ages from 11 to 19 were in the longitudinal analyses for the current study. The findings demonstrated that sibling and best friends' substance use explained white adolescents' cigarette and alcohol use, whereas Black adolescents' cigarette and alcohol use was predominantly explained by siblings' substance use. Ultimately, the results indicated the nuanced role that two types of peers have in explaining variation in substance use across Black and White adolescents.

Understanding sibling influence on adolescents' alcohol use: Social and cognitive pathways

Research indicates that older siblings uniquely influence their younger brothers' and sisters' substance use behaviors during adolescence; however, the underlying mechanisms of socialization are rarely examined. The present study investigated whether social and/or cognitive pathways mediated the association between adolescent siblings' alcohol use and whether these pathways were moderated by the gender composition of the sibling dyad. Participants included one parent and two adolescent siblings (M age=14.52 and 17.17years) from 326 families. Data were collected via telephone interviews. Path analysis demonstrated that the association between older and younger siblings' alcohol use was mediated via social and cognitive pathways. Specifically, older siblings' drinking was positively related to the frequency of siblings' co-use as well as more positive expectations about alcohol, which in turn were positively associated with younger siblings' alcohol use. Identifying the ways in which siblings influence each other's substance use and health is critical because they are emerging and effective targets of intervention and prevention.

Parent involvement, sibling companionship, and adolescent substance use: A longitudinal, genetically informed design

A large literature shows that parent and sibling relationship factors are associated with an increased likelihood of adolescent substance use. Less is known about the etiology of these associations. Using a genetically informed sibling design, we examined the prospective associations between parent involvement, sibling companionship, and adolescent substance use at 2 points in mid- and late-adolescence. Adolescents were adopted (n = 568) or the biological offspring of both parents (n = 412). Cross-lagged panel results showed that higher levels of parent involvement in early adolescence were associated with lower levels of substance use later in adolescence. Results did not significantly differ across adoption status, suggesting this association cannot be due to passive gene-environment correlation. Adolescent substance use at Time 1 was not significantly associated with parent involvement at Time 2, suggesting this association does not appear to be solely due to evocative (i.e., "child-driven") effects either. Together, results support a protective influence of parent involvement on subsequent adolescent substance use that is environmental in nature. The cross-paths between sibling companionship and adolescent substance use were significant and negative in direction (i.e., protective) for sisters, but positive for brothers (in line with a social contagion hypothesis). These effects were consistent across genetically related and unrelated pairs, and thus appear to be environmentally mediated. For mixed gender siblings, results were consistent with environmentally driven, protective influence hypothesis for genetically unrelated pairs, but in line with a genetically influenced, social contagion hypothesis for genetically related pairs. Implications are discussed.