Sibling effects on substance use in adolescence: social contagion and genetic relatedness

Does depression co-occur within households? The moderating effects of financial resources and job insecurity on psychological contagion

The empirically related psychopathologies of stress and depression exact an enormous economic toll and have many physical and behavioral health effects. Most studies of the effects of stress and depression focus on their causes and consequences for a single, focal individual. We examine the extent to which depression, as indicated by filling antidepressant prescriptions (SSRI and Benzodiazepines), co-occurs across spouses, constituting a negative spillover effect. To better understand the conditions that affect within-household contagion of depression, we examine whether the stress and uncertainty occasioned by job change and financial stress (net worth) increases spillover effects among spouses.

We use panel data from various Danish administrative registers from the year 2001–2015 with more than 4.5 million observations on more than 900,000 unique individuals and their spouses from Danish health registers.

Spouses in a household with their partner using antidepressants have a 62.1% higher chance of using antidepressants themselves, with the one year lagged effect being 29.3% and a two-year lagged effect of 15.1%. The effects become larger by 14.8% contemporaneously and 20% in the two-year lagged model if the focal individual changed employers. There was also a substantively unimportant effect of lower financial wealth to increase inter-spousal contagion.

Family Health Development: A Theoretical Framework

In recognition of the family as central to health, the concept of family, rather than individual, health has been an important area of research and, increasingly, clinical practice. There is a need to leverage existing theories of family health to align with our evolving understanding of Life Course Health Development, including the opportunities and constraints of the family context for promoting lifelong individual and population health. The purpose of this article is to propose an integrative model of family health development within a Life Course Health Development lens to facilitate conceptualization, research, and clinical practice. This model provides an organizing heuristic model for understanding the dynamic interactions between family structures, processes, cognitions, and behaviors across development. Potential applications of this model are discussed.

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.

Where You Lead, I Will Follow: Exploring Sibling Similarity in Brain and Behavior During Risky Decision Making

This exploratory study examined whether social learning increases similarity in adolescent siblings' behavior and neural patterns during risky decision making. Participants included 86 adolescents (43 sibling dyads; younger siblings: M_age  = 12.2 years; 22 females; older siblings: M_age  = 14.6 years; 20 females) who completed questionnaires, and a decision-making task during an fMRI scan. Younger siblings became more similar to their older siblings' risky decision making after observing their older sibling take risks). Younger siblings who reported greater modeling of their older sibling, and less differentiation from them, showed increased neural similarity to their older siblings in the ventromedial prefrontal cortex, and the right anterior insula and ventral striatum, respectively. These findings highlight siblings as salient social agents in how adolescents process risky decision making.

Older Siblings as Academic Socialization Agents for Younger Siblings: Developmental Pathways across Adolescence

The role of older siblings in younger siblings' academic socialization becomes increasingly salient during adolescence. This longitudinal study examines the developmental mechanisms through which older siblings shape younger siblings' academic outcomes and whether older siblings' peer affiliations predict younger siblings' educational aspirations and attainment. Data consisted of responses from 395 target adolescents (M_age = 12.22 years, 48.9% female; 51.6% African American, 38.5% European American) and their older siblings (M_age = 14.65 years, 50.1% female) across nine years. The findings showed that older siblings' affiliation with academically disengaged peers at 7th grade predicted younger siblings' decreased affiliation with academically engaged peers and increased affiliation with disengaged peers at 9th grade. In addition, younger siblings' affiliation with academically engaged peers predicted greater educational aspirations at 11th grade, which in turn were related to higher postsecondary educational attainment. The identification of developmental processes through which older siblings were associated with younger siblings' academic success may aid in creating supportive social environments in which adolescents can thrive.

Neural correlates of sibling closeness and association with externalizing behavior in adolescence

Sibling relationships have been linked to adolescent externalizing behaviors, but the neurobiological factors that underlie this association have not been identified. This study investigated sibling closeness and birth order as a predictor of adolescent externalizing behavior via differences in neural processes during safe decision-making. A total of 77 adolescents (range = 12–15 years, M_age = 13.45 years, 40 females) completed a computerized driving task during a functional MRI scan. Results showed that adolescents’ perceptions of sibling closeness were associated with greater neural activation in the anterior insula, ventral striatum and left ventrolateral prefrontal cortex when making safe decisions, suggesting that the quality of sibling relationships modulates adolescent neurocognition even without being present. Furthermore, moderated mediation analyses revealed that higher sibling closeness was associated with lower externalizing behavior via left anterior insula activation during safe decision-making, but only for adolescents without older siblings (i.e. eldest children) compared to adolescents who had multiple older siblings. Importantly, these findings persisted above and beyond parental and peer closeness and sibling characteristics (i.e. sex, relatedness, birth order), highlighting the significant influence of sibling relationships on adolescent externalizing behavior through the brain.

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.

Concurrent child history and contextual predictors of children's internalizing and externalizing behavior problems in foster care

This study contributes to current research on the behavior problems of children in foster care by analyzing a more comprehensive set of concurrent child history and contextual predictors. Kinship home status and sibling status (i.e., whether the sibling was a biological sibling to the foster child) were evaluated as moderators of significant associations. Data were collected at the baseline of a foster parent training intervention program prior to any intervention services using parent phone interviews (N= 310, 51.6% male, M age = 7.57 years). Two linear hierarchical regressions were used to evaluate each set of predictors' association with behavior problems as well as each individual predictor's contribution. Results indicated that as a set, the contextual variables predicted a significant and unique amount of variability in the child's internalizing and externalizing behavior scores, but the child history variables did not. Specifically, the child's placement in a non-kinship home, being in a non-ethnically matched child-parent pair, higher parent stress scores, a greater number of prior group home placements, and higher internalizing behavior scores for the child predicted higher child externalizing scores. Higher parent stress scores, higher focal sibling externalizing behavior scores, and higher externalizing behavior scores for the child predicted higher internalizing scores for the child. The association between focal sibling externalizing behavior scores and child internalizing scores was moderated by kinship home status, such that there was a stronger association between the focal sibling's externalizing score and the child's internalizing score if the child was in a kinship compared to a non-kinship home. Implications for intervention services are discussed, particularly the importance of assessing the child's foster home environment when addressing the child's behavior problems.

Siblings and Adolescent Weapon Carrying: Contributions of Genetics, Shared Environment, and Nonshared Environment

Many past studies have observed evidence of sibling similarity and influence for delinquency and substance use. However, studies of sibling similarity for adolescent weapon carrying, particularly for weapons beyond firearms, are largely absent from the literature. The present study assesses sibling similarity in weapon carrying as well as the relative contributions of genetics, shared environment, and nonshared environment. Data are obtained from the first two waves of the National Longitudinal Study of Adolescent to Adult Health and analyzed using biometrical genetic models for twins and actor-partner interdependence models for nontwins. Results indicate little, if any, contribution stemming from genetics. There is also no evidence of a significant shared environment effect. Instead, all or nearly all of the variation and similarity in weapon carrying among siblings are related to the nonshared environment, particularly gang affiliation. Implications and possible extensions of these findings are discussed.

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.

Progression in substance use initiation: A multilevel discordant monozygotic twin design

Considerable attention has been paid to the "gateway" pattern of drug use initiation in which individuals progress from tobacco and alcohol use to cannabis and other illicit drugs. The extent to which this sequence reflects a causal impact of licit substance use on illicit substance involvement remains unclear. Clarifying the mechanisms underlying substance use initiation may help inform our understanding of risk for psychopathology, as increasing research is demonstrating associations between initiation patterns and heavier involvement. This study examined patterns of substance use initiation using a discordant twin design. Participants were 3,476 monozygotic twins (37% male) from the Australian Twin Registry who reported on their ages of tobacco, alcohol, and cannabis initiation. Multilevel proportional hazard regression models were used to (a) estimate within-twin-pair and between-twin-pair contributions to associations between the ages of onset of different drugs; and (b) examine whether the magnitude of effects differed as a function of the order of substance use initiation. Finding significant effects within twin pairs would support the hypothesis that the age of initiation of a substance causally influences the age of initiation of a subsequent substance. Finding significant effects between twin pairs would support the operation of familial influences that explain variation in the ages of initiation of multiple drugs. Within-twin-pair effects for typical patterns were modest. When initiation was atypical, however, larger within-twin-pair effects were observed and causal influences were more strongly implicated. Results support the utility of examining the timing and ordering of substance use initiation within sophisticated, genetically informative designs.

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

Previous research has shown adolescent siblings are similar in their alcohol use and that this similarity is largely due to their shared environment. Using a genetically-informed sibling sample (196 full-biological pairs, 384 genetically unrelated pairs), we confirmed that the extent to which older siblings facilitate younger siblings' alcohol use (i.e., help them get alcohol) was one factor contributing to this shared environmental association. All analyses controlled for parent and peer influences. Findings were not moderated by sibling differences in genetic relatedness, gender, or ethnicity. Proximity in sibling age strengthened these associations, somewhat. Results were especially strong for sibling pairs where the older sibling was of legal drinking age. Implications for prevention and intervention are discussed.

Sibling relationships as sources of risk and resilience in the development and maintenance of internalizing and externalizing problems during childhood and adolescence

Sibling relationships are a unique and powerful context for children's development, characterized by strong positive features, such as warmth and intimacy, as well as negative qualities like intense, potentially destructive conflict. For these reasons, sibling interactions may be both a risk and a protective factor for the development and maintenance of emotional and behavioral dysfunction. We review evidence indicating that sibling interactions are linked to internalizing and externalizing symptoms and identify possible mechanisms for these associations. Sibling conflict contributes uniquely to symptomatology and may be particularly problematic when accompanied by lack of warmth, which is generally associated with decreased internalizing and externalizing problems. On the other hand, greater warmth can be associated with heightened externalizing symptoms for later-born children who may model the behavior of older siblings. Although it will be important to monitor for increased sibling collusion, several intervention studies demonstrate that it is possible to reduce conflict and increase warmth between brothers and sisters, and that improving sibling interactions can teach children social-cognitive skills that are beneficial in other relationships (e.g., friendships). Developing brief assessment tools differentiating normative from pathogenic sibling conflict would assist clinical decision making. Future intervention work could provide a more stringent test of the hypothesis that strengthening sibling relationships improves children's socio-emotional adjustment.

Risk and protective factors for sexual and dating violence victimization: a longitudinal, prospective study of Latino and African American adolescents

Teen dating violence and sexual victimization are serious public health concerns. Although research has highlighted the correlates and consequences of such abuse, little is known about early antecedents. The current study sought to identify the risk and protective factors evident in early adolescence that are associated with sexual and dating violence victimization in late adolescence. The sample involved 236 (52% female) low-income Latino (69%) and African American (31%) youth, their older sisters, and their mothers who were studied when youth were, on average, ages 13 and 18 years. The results indicated that early indicators of a risky lifestyle (e.g., getting drunk, having sex) and having deviant friends and siblings were associated with a higher likelihood of subsequent victimization. Mothers' early strictness, monitoring, and conservative sexual attitudes predicted a lower likelihood of subsequent assault and served as significant buffers given specific risks, particularly for girls and Latinos. The findings suggest that behavior and social network patterns established relatively early in life increase one's vulnerability to victimization later in life, as well as point to aspects of parenting that serve a protective function against such outcomes.

The schooling of offspring and the survival of parents

Contemporary stratification research on developed societies usually views the intergenerational transmission of educational advantage as a one-way effect from parent to child. However, parents' investment in their offspring's schooling may yield significant returns for parents themselves in later life. For instance, well-educated offspring have greater knowledge of health and technology to share with their parents and more financial means to provide for them than do their less-educated counterparts. We use data from the 1992-2006 Health and Retirement Study (HRS) to examine whether adult offspring's educational attainments are associated with parents' survival in the United States. We show that adult offspring's educational attainments have independent effects on their parents' mortality, even after controlling for parents' own socioeconomic resources. This relationship is more pronounced for deaths that are linked to behavioral factors: most notably, chronic lower respiratory disease and lung cancer. Furthermore, at least part of the association between offspring's schooling and parents' survival may be explained by parents' health behaviors, including smoking and physical activity. These findings suggest that one way to influence the health of the elderly is through their offspring. To harness the full value of schooling for health, then, a family and multigenerational perspective is needed.

Externalizing Disorders and Environmental Risk: Mechanisms of Gene-Environment Interplay and Strategies for Intervention

Though heritable, externalizing disorders have a number of robust associations with several environmental risk factors, including family, school, and peer contexts. To account for these associations, we integrate a behavioral genetic perspective with principles of a developmental cascade theory of antisocial behavior. The major environmental contexts associated with child externalizing problems are reviewed, as are the processes of gene-environment interplay underlying these associations. Throughout, we discuss implications for prevention and intervention. Three major approaches designed to reduce child externalizing behavior are reviewed. Prevention and intervention programs appear to be most successful when they target individuals or communities most at risk for developing externalizing disorders, rather than applied universally. We end by commenting on areas in need of additional research concerning environmental influences on persistent externalizing behaviors.

Alcohol and Substance Use in Adolescence and Young Adulthood: The Role of Siblings

Interpersonal relationships both within and outside the family have been a central part of alcohol and substance use research. Many studies have focused on the role of parents and peers; fewer studies have focused on siblings. This paper examined siblings' roles in ATOD use patterns and trajectories in the context of familial and non-familial factors across time. First, intraclass correlations (ICCs) were used to examine the degree to which older siblings' ATOD use was associated with younger siblings' ATOD use. Second, hierarchical regression analyses were conducted to examine the degree to which individual, parent, sibling and peer factors over time were associated with adolescents' and young adults' ATOD use. It should be noted that developmentally proximal predictors were utilized in these models and within-family replication was also examined. Results demonstrate strong associations between older and younger siblings' ATOD use. Moreover, the developmentally proximal sibling variables were predictive of younger sibling ATOD use in the context of other variables across all substances. Study findings are discussed in terms of identifying promising and potentially malleable points of intervention for future investigators.

How effective and cost-effective was the national mass media smoking cessation campaign 'Stoptober'?

BACKGROUND

A national smoking cessation campaign based on behaviour change theory and operating through both traditional and new media was launched across England during late 2012 ('Stoptober'). In addition to attempting to start a movement in which smokers would quit at the same time in response to a positive mass quitting trigger, the campaign set smokers the goal of being smoke-free for October and embodied other psychological principles in a range of tools and communications.

METHODS

Data on quit attempts were obtained from 31,566 past-year smokers during nationally representative household surveys conducted monthly between 2007 and 2012. The effectiveness of the campaign was assessed by the increase in national quit attempt rate in October relative to other months in 2012 vs. 2007-2011.

RESULTS

Relative to other months in the year, more people tried to quit in October in 2012 compared with 2007-2011 (OR=1.79, 95%CI=1.20-2.68). In 2012 there was an approximately 50% increase in quitting during October compared with other months of the same year (9.6% vs. 6.6%; OR=1.50, 95%CI=1.05-2.15), whereas in 2007-2011 the rate in October was non-significantly less than in other months of the same period (6.4% vs. 7.5%; OR=0.84, 95%CI=0.70-1.00). Stoptober is estimated to have generated an additional 350,000 quit attempts and saved 10,400 discounted life years (DLY) at less than £415 per DLY in the modal age group.

CONCLUSIONS

Designing a national public health campaign with a clear behavioural target (making a serious quit attempt) using key psychological principles can yield substantial behaviour change and public health impact.

Siblings are special: initial test of a new approach for preventing youth behavior problems

PURPOSE

A growing body of research documents the significance of siblings and sibling relationships for development, mental health, and behavioral risk across childhood and adolescence. Nonetheless, few well-designed efforts have been undertaken to promote positive and reduce negative youth outcomes by enhancing sibling relationships.

METHODS

Based on a theoretical model of sibling influences, we conducted a randomized trial of Siblings Are Special (SIBS), a group-format afterschool program for fifth graders with a younger sibling in second through fourth grades, which entailed 12 weekly afterschool sessions and three Family Nights. We tested program efficacy with a pre- and post-test design with 174 families randomly assigned to condition. In home visits at both time points, we collected data via parent questionnaires, child interviews, and observer-rated videotaped interactions and teachers rated children's behavior at school.

RESULTS

The program enhanced positive sibling relationships, appropriate strategies for parenting siblings, and child self-control, social competence, and academic performance; program exposure was also associated with reduced maternal depression and child internalizing problems. Results were robust across the sample, not qualified by sibling gender, age, family demographics, or baseline risk. No effects were found for sibling conflict, collusion, or child externalizing problems; we will examine follow-up data to determine if short-term impacts lead to reduced negative behaviors over time.

CONCLUSIONS

The breadth of the SIBS program's impact is consistent with research suggesting that siblings are an important influence on development and adjustment and supports our argument that a sibling focus should be incorporated into youth and family-oriented prevention programs.

Longitudinal associations between sibling relationship qualities and risky behavior across adolescence

This study examined the associations between sibling intimacy and conflict and youths' reports of risky behavior in a sample of adolescents ages 11-20. Participants were mothers, fathers, and sibling dyads in 393 families who were interviewed annually for 3, 4, or 5 years. Multivariate multilevel models tested longitudinal links between sibling intimacy and conflict and youths' risky behavior and whether these associations were moderated by birth order, sex, or dyad sex constellation. Controlling for parent-youth conflict, the results showed positive within-person covariation between sibling conflict and risky behavior for all youths except firstborns with younger brothers. Controlling for parent-youth intimacy, sibling intimacy was positively linked with risky behavior at the between-person level, but only in brother-brother pairs. The discussion focuses on sibling relationships as a context for adolescents' individual development and the roles of birth order, sex, and dyad sex constellation.

Similarities and differences in adolescent siblings' alcohol-related attitudes, use, and delinquency: evidence for convergent and divergent influence processes

A growing body of research indicates that siblings influence each other's risky and deviant behaviors during adolescence. Guided by research and theory on sibling similarities and differences, this study examined the operation and implications of three different influence processes--social learning, shared friends, and sibling differentiation--during adolescence. Participants included one parent and two adolescent siblings (earlier born age: M = 17.17 years, SD = 0.94; later born age: M = 14.52 years, SD = 1.27) from 326 families. Data were collected via telephone interviews. Using reports from both older and younger siblings, two-stage cluster analyses revealed three influence profiles: mutual modeling and shared friends, younger sibling admiration, and differentiation. Additional analyses revealed that mutual modeling and shared friends as well as younger sibling admiration were linked to similarities in brothers' and sisters' health-risk behaviors and attitudes, whereas differentiation processes were associated with divergence in siblings' characteristics. The discussion focuses on refining the study of sibling influence, with particular attention paid to the operation and implications of both convergent and divergent influence processes.

A sibling death in the family: common and consequential

Although a large literature analyzes the determinants of child mortality and suggests policy and medical interventions aimed at its reduction, there is little existing analysis illuminating the consequences of child mortality for other family members. In particular, there is little evidence exploring the consequences of experiencing the death of a sibling on one's own development and transition to adulthood. This article examines the prevalence and consequences of experiencing a sibling death during one's childhood using two U.S. data sets. We show that even in a rich developed country, these experiences are quite common, affecting between 5 % and 8 % of the children with one or more siblings in our two data sets. We then show that these experiences are associated with important reductions in years of schooling as well as a broad range of adult socioeconomic outcomes. Our findings also suggest that sisters are far more affected than brothers and that the cause of death is an important factor in sibling effects. Overall, our findings point to important previously unexamined consequences of child mortality, adding to the societal costs associated with childhood mortality as well as suggesting additional benefits from policy and medical innovations aimed at curbing both such deaths and subsequent effects on family members.

Members, isolates, and liaisons: meta-analysis of adolescents' network positions and their smoking behavior

Existing research finds that peer networks play an important role in adolescents' smoking behaviors. To evaluate this research, meta-analysis was utilized to investigate the relationship between social positions (e.g., group members vs. isolates vs. liaisons) in friendship networks and smoking behaviors. The results (N = 5,067, k = 8) showed that adolescents from multiple countries who are isolated in friendship networks are more likely to report smoking behaviors than those with friends (members or liaisons). The results also show that these differential odds of smoking based on network position has decreased over the past 15 years.

Similarities in adolescent siblings' substance use: testing competing pathways of influence

OBJECTIVE

An accumulating body of work indicates that siblings uniquely influence each other's alcohol and substance use behaviors during adolescence. The mechanisms underlying these associations, however, are unknown because most studies have not measured sibling influence processes. The present study addressed this gap by exploring the links between multiple influence processes and sibling similarities in alcohol and substance use.

METHOD

The sample included one parent and two adolescent siblings (earlier born age: M = 17.17 years, SD = 0.94; later born age: M = 14.52 years, SD = 1.27) from 326 families. Data were collected via telephone interviews with parents and the two siblings.

RESULTS

A series of logistic regressions revealed that, after parents' and peers' use as well as other variables including parenting was statistically controlled for, older siblings' alcohol and other substance use was positively associated with younger siblings' patterns of use. Furthermore, sibling modeling and shared friends were significant moderators of these associations. For adolescents' alcohol use, the links between sibling modeling and shared peer networks were interactive, such that the associations between modeling and similarity in alcohol use were stronger when siblings shared friends.

CONCLUSIONS

Future research should continue to investigate the ways in which siblings influence each other because such processes are emerging targets for intervention and prevention efforts.

Peer deviance, alcohol expectancies, and adolescent alcohol use: explaining shared and nonshared environmental effects using an adoptive sibling pair design

Previous research suggests adolescent alcohol use is largely influenced by environmental factors, yet little is known about the specific nature of this influence. We hypothesized that peer deviance and alcohol expectancies would be sources of environmental influence because both have been consistently and strongly correlated with adolescent alcohol use. The sample included 206 genetically related and 407 genetically unrelated sibling pairs assessed in mid-to-late adolescence. The heritability of adolescent alcohol use (e.g., frequency, quantity last 12 months) was minimal and not significantly different from zero. The associations among peer deviance, alcohol expectancies, and alcohol use were primarily due to shared environmental factors. Of special note, alcohol expectancies also significantly explained nonshared environmental influence on alcohol use. This study is one of few that have identified specific environmental variants of adolescent alcohol use while controlling for genetic influence.

Four factors for the initiation of substance use by young adulthood: a 10-year follow-up twin and sibling study of marital conflict, monitoring, siblings, and peers

This study examined genetic and environmental influences on associations among marital conflict about the child, parental monitoring, sibling relationship negativity, and peer delinquency during adolescence and initiation of illegal drug use by young adulthood. The sample comprised data collected longitudinally from same-sex sibling pairs and parents when the siblings were 10-18 years old (M = 14.5 and 12.9 years for Child 1 and Child 2, respectively) and 20-35 years old (M = 26.8 and 25.5 years for Child 1 and Child 2, respectively). Findings indicate four factors that explain the initiation of illegal drug use: two shaped by genetic influences and two shaped by environments shared by siblings. The two genetically shaped factors probably have distinct mechanisms: one a child-initiated coercive process in the family and the other parent and peer processes shaped by the child's disclosure. The environmentally influenced factors seem distinctively shaped by poor parental monitoring of both sibs and the effects of siblings on each other's deviancy.

Enhancing sibling relationships to prevent adolescent problem behaviors: theory, design and feasibility of Siblings Are Special

Siblings play a significant but neglected role in family socialization dynamics, and focusing on the sibling relationship is a non-stigmatizing point of entry into the family for prevention programming. Siblings are Special (SAS) was designed as a universal program that targets both sibling relationship and parenting mediating processes in middle childhood to prevent behavior problems in adolescence. We describe the theoretical framework underlying SAS, the SAS curriculum, and the feasibility of the program based on a study of 128 middle-childhood aged sibling dyads. Data on the quality of program implementation, program fidelity, siblings' engagement, and ratings of impact indicated the SAS program was acceptable to families and schools, that the curriculum could be implemented with high fidelity, that siblings and parents participated at high levels and were highly engaged, and that, from the perspective of group leaders, school administrators and parents, the program had a positive impact on the siblings.

Invited commentary: does the childhood environment influence the association between every x and every y in adulthood?

The conditions under which children are raised have a long-term impact on health throughout the life course. Because childhood conditions can have such a strong influence on adult risk factors for disease, failure to account for their influences could distort observed associations between adult risk factors and subsequent health outcomes. In other words, childhood conditions could confound the association between every X and Y when X is measured in adulthood. Comparisons of health outcomes between exposed and unexposed siblings have the potential to eliminate confounding effects due to vulnerability factors shared between siblings (i.e., 50% of their genes and aspects of the childhood environment that affect siblings equally). In a large, population-based study of siblings in Denmark, Søndergaard et al. (Am J Epidemiol. 2012;176(8):675-683) found that individuals with higher educational qualifications lived longer than did their siblings with lower educational qualifications. Their results provide evidence for the returns to health resulting from investment in expanded educational opportunities. However, even sibling designs are not conclusive regarding causality; they remain subject to the unmeasured confounding influences of factors that vary within families. Nonetheless, sibling-based approaches should be used more often in studies of adult risk factors to address the long-term influences of the childhood environment on health.

Sibling Relationships and Influences in Childhood and Adolescence

The authors review the literature on sibling relationships in childhood and adolescence, starting by tracing themes from foundational research and theory and then focusing on empirical research during the past 2 decades. This literature documents siblings' centrality in family life, sources of variation in sibling relationship qualities, and the significance of siblings for child and adolescent development and adjustment. Sibling influences emerge not only in the context of siblings' frequent and often emotionally intense interactions but also by virtue of siblings' role in larger family system dynamics. Although siblings are building blocks of family structure and key players in family dynamics, their role has been relatively neglected by family scholars and by those who study close relationships. Incorporating study of siblings into family research provides novel insights into the operation of families as social and socializing systems.

The third rail of family systems: sibling relationships, mental and behavioral health, and preventive intervention in childhood and adolescence

Sibling relationships are an important context for development, but are often ignored in research and preventive interventions with youth and families. In childhood and adolescence, siblings spend considerable time together, and siblings' characteristics and sibling dynamics substantially influence developmental trajectories and outcomes. This paper reviews research on sibling relationships in childhood and adolescence, focusing on sibling dynamics as part of the family system and sibling influences on adjustment problems, including internalizing and externalizing behaviors and substance use. We present a theoretical model that describes three key pathways of sibling influence: one that extends through siblings' experiences with peers and school, and two that operate largely through family relationships. We then describe the few existing preventive interventions that target sibling relationships and discuss the potential utility of integrating siblings into child and family programs.

Friends moderate the effects of pro-smoking media on college students' intentions to smoke

Exposure to prosmoking media (e.g., smoking in movies, advertising in magazines) contributes to smoking in young people. However, the extent to which the impact of exposure depends on the social context in which those exposures occur has not been investigated. This study used ecological momentary assessment to examine the moderating role of social context in the relationship between college students' exposure to prosmoking media and their smoking refusal self-efficacy and intention to smoke. College students (n = 134) carried handheld computers for 21 days, recording their exposure to all forms of prosmoking media during the assessment period. They also responded to three investigator-initiated control prompts (programmed to occur randomly) each day of the assessment. After each exposure to prosmoking media and after each control prompt, participants answered questions about smoking refusal self-efficacy and their intentions to smoke; they also indicated whether they were with friends, with family, with a romantic partner, or alone (i.e., their social context). When participants were with friends, prosmoking media exposures were associated with stronger smoking intentions and lower smoking refusal self-efficacy; these associations were not present when participants were alone. Being with family members or with a romantic partner did not moderate the impact of prosmoking media exposure on either dependent variable. These results suggest a new role for peers in the development of youth smoking.

Behavioral resilience in the post-genomic era: emerging models linking genes with environment

One of the most important deliverables of the post-genomic era has been a new and nuanced appreciation of how the environment shapes—and holds potential to alter—the expression of susceptibility genes for behavioral dimensions and disorders. This paper will consider three themes that have emerged from cutting-edge research studies that utilize newer molecular genetic approaches as well as tried-and-true genetic epidemiological methodologies, with particular reference to evolving perspectives on resilience and plasticity. These themes are: (1) evidence for replicable and robust shared environmental effects on a number of clinically relevant behaviors in childhood and adolescence; (2) evolving research on gene-environment interaction; and (3) a newer focus on differential susceptibility and plasticity. The net sum of these themes is that consideration of genetic effects on behavioral dimensions and disorders needs to be connected to thinking about the role of environment as a potent source for promoting resilience and change.

DIFFERENTIAL SUSCEPTIBILITY TO CONTEXT: A PROMISING MODEL OF THE INTERPLAY OF GENES AND THE SOCIAL ENVIRONMENT

The goal of this chapter is to demonstrate the importance of incorporating gene by environment (GxE) interactions into behavioral science theory and research. In pursuit of this aim, the chapter is organized in the following way. First, we provide a brief critique of the behavioral genetics paradigm, noting why one should be skeptical of its suggestion that genes exert large main effects, and only main effects, on social behavior. Second, we describe how the recent mapping of the human genome has facilitated molecular genetic research and the emergence of the new epigenetic paradigm that has begun to supplement and replace the simpler model of genetic determinism. Third, we turn our focus to the explosion of GxE research that has occurred in the wake of this paradigmatic shift. These studies find that genetic variation often interacts with environmental context to influence the probability of various behaviors. Importantly, in many, and perhaps most, of these studies the genetic variable, unlike the environmental variable, has little if any main effect on the outcome of interest. Rather, the influence of the genetic variable is limited to its moderation of the effect of the environmental construct. Such research does not undermine the importance of environmental factors; rather it shows how social scientific explanations of human behavior might be made more precise by incorporating genetic information. Finally, we consider various models of gene - environment interplay, paying particular attention to the differential susceptibility to context perspective. This model of GxE posits that a substantial proportion of the population is genetically predisposed to be more susceptible than others to environment influence. We argue that this model of GxE is particularly relevant to sociologists and psychologists.

Family relationships and children's stress responses

In this chapter, the theoretical and empirical associations between family relationships and children's responses to stressors are reviewed. Family relationships explored are primarily dyadic, representing the emphasis of past empirical research; these include parent-parent, parent-child, and sibling relationships. However, in recognition of the more complicated and interconnected nature of family relationships, also reviewed are associations between the broader family context and children's stress responses. Multiple measures of stress responses are considered, including both physiological and emotional responses to and recovery from stressful experiences. Overall, the studies reviewed suggest that poor-quality family environments, including those characterized by low emotional support or high conflict, are associated with dysregulated stress responses throughout childhood and adolescence. In contrast, children and adolescents in families with high emotional support or low conflict seem to be protected from developing stress regulatory problems. Limitations in this body of research as well as directions for future research are discussed.

Motor disorder and anxious and depressive symptomatology: a monozygotic co-twin control approach

The aim of this study was to investigate the relationship between poor motor ability and anxious and depressive symptomatology in child and adolescent monozygotic twins. The co-twin control design was used to explore these mental health issues in MZ twins concordant and discordant for a motor disorder, and controls. This methodology offers the unique opportunity to control for genetic effects and shared environmental influences, and permits the investigation of non-shared environmental influences. The Developmental Coordination Disorder Questionnaire was used to identify 23 sets of twins discordant for a motor disorder, 23 sets concordant for a motor disorder, and 773 sets of twins with no motor disorder from a total sample of 2122 Australian sets of twins. The Strengths and Weaknesses of ADHD Symptoms and Normal Behaviour questionnaire was used to exclude participants with high Attention Deficit Hyperactivity Disorder symptomatology. Anxious and depressive symptomatology were assessed using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) based questionnaires on Generalised Anxiety Disorder and Sad Affect. Results indicated significantly higher levels of anxious and depressive symptomatology in twins with a motor disorder in discordant pairs compared to their co-twins without a motor disorder, and controls. There were significantly higher levels of anxious symptomatology in twins with a motor disorder in discordant sets than in sets of twins concordant for a motor disorder. There were significantly higher levels of anxious symptomatology in concordant twins than in controls. Implications of these findings are discussed with emphasis on understanding and recognising the relationship between a motor disorder and anxious and depressive symptomatology in clinical practice for children and adolescents with these disorders.

The relative contributions of parents and siblings to child and adolescent development

Guided by an ecological framework, we explore how siblings' and parents' roles, relationships, and activities are intertwined in everyday life, providing unique and combined contributions to development. In a departure from past research that emphasized the separate contributions of siblings and parents to individual development, we find that examining the conjoint or interactive effects of sibling and parent influences promises to extend our understanding of the role of family in children's and adolescents' social, emotional, and cognitive development. Understood within the context of family and sociocultural characteristics, siblings' unique roles as agents of socialization are illuminated.

Mechanisms of sibling socialization in normative family development

Siblings are important sources of social influence throughout childhood and adolescence. Nevertheless, the processes by which siblings influence one another remain relatively unexplored. We highlight two theories of sibling influence-sibling deidentification and social learning-that offer insights as to how and why siblings develop similar and different attributes, attitudes, and behaviors. Recognizing the need to move past post hoc explanations, we suggest several directions for how these two influence processes can be measured directly in future work. Research on sibling influence also can be improved by integrating these theories and attending to their domains of influence.

Monozygotic twins concordant and discordant for DCD: two sides to the story

Being an identical twin does not necessarily mean having identical perceptions of family functioning, nor of the twin relationship. Using the co-twin control design, the aim of this study was to explore perceptions of family dynamics and the twin relationship in monozygotic (MZ) twins discordant and concordant for Developmental Coordination Disorder (DCD). It was hypothesized that, as has been found in twins discordant for cerebral palsy, twins without DCD would perceive family functioning as less healthy than would their co-twins with DCD. It was also hypothesized that the twin relationship would be regarded generally as mutually supportive. Questionnaire data on 866 sets of MZ twins aged 6 to 17 years were used to identify seven sets discordant, and two sets concordant for DCD. Quantitative (General Functioning Scale of the Family Assessment Device - FAD), and qualitative (semi-structured interview) measures were used to assess family dynamics and the twin relationship. In discordant sets, six of seven twins without DCD rated family functioning at a less healthy level than did their co-twins with DCD. All twins in the DCD concordant sets rated their family functioning at a healthy level. From the semi-structured interviews, emergent themes included friendship, support, minimal sibling rivalry, and minor difficulties. It was concluded that, overall, the twin relationship was regarded as close and mutually supportive, with an ambivalent polarity between the best and most difficult aspects of being an identical twin. Implications for research, policy and clinical practice are discussed.

Genetic Thinking in the Study of Social Relationships: Five Points of Entry

For nearly a generation, researchers studying human behavioral development have combined genetically informed research designs with careful measures of social relationships such as parenting, sibling relationships, peer relationships, marital processes, social class stratifications, and patterns of social engagement in the elderly. In what way have these genetically informed studies altered the construction and testing of social theories of human development? We consider five points of entry where genetic thinking is taking hold. First, genetic findings suggest an alternative scenario for explaining social data. Associations between measures of the social environment and human development may be due to genes that influence both. Second, genetic studies add to other prompts to study the early developmental origins of current social phenomena in midlife and beyond. Third, genetic analyses promise to shed light on understudied social systems, such as sibling relationships, that have an impact on human development independent of genotype. Fourth, genetic analyses anchor in neurobiology individual differences in resilience and sensitivity to both adverse and favorable social environments. Finally, genetic analyses increase the utility of laboratory simulations of human social processes and of animal models.

Genetic and environmental influences upon the CBCL/6-18 DSM-oriented scales: similarities and differences across three different computational approaches and two age ranges

Inasmuch as the newly established DSM-oriented CBCL/6-18 scales are to be increasingly employed to assess clinical/high-risk populations, it becomes important to explore their aetiology both within the normal- and the extreme range of variation in general population samples and to compare the results obtained in different age groups. We investigated by the Quantitative Maximum Likelihood, the De Fries-Fulker, and the Ordinal Maximum Likelihood methods the genetic and environmental influences upon the five DSM-oriented CBCL/6-18 scales in 796 twins aged 8-17 years belonging to the general population-based Italian Twin Registry. When children were analysed together regardless of age, most best-fitting solutions yielded genetic and non-shared environmental factors as the sole influences for DSM-oriented CBCL/6-18 behaviours, both for the normal and the extreme variations. When analyses were conducted separately for two age groups, shared environmental influences emerged consistently for Affective and Anxiety Problems in children aged 8-11. Oppositional-Defiant, Attention Deficit/Hyperactivity, and Conduct Problems appeared-with few exceptions-influenced only by genetic and non-shared environmental factors in both age groups, according to all three computational approaches. The De Fries-Fulker method appeared to be more sensitive in detecting shared environmental effects. Analysing the same set of data with different analytic approaches leads to better-balanced views on the aetiology of psychopathological behaviours in the developmental years.

The Nature and Correlates of Sibling Influence in Two-Parent African American Families

Guided by research and theory on sibling similarities and differences, this study explored the nature and correlates of two processes of sibling influence-social learning and sibling differentiation-during adolescence. Participants included two adolescent-aged siblings (M = 16.29 years for older siblings and M = 12.59 years for younger siblings, respectively) from 166 two-parent African American families. Significant nonlinear associations between these two influence dynamics and some sibling relationship qualities were discovered. For sibling differentiation, but not social learning, these links were further moderated by sex composition of the sibling dyad. Additional analyses revealed that youths' reports of social learning were generally linked to smaller differences between siblings, whereas differentiation processes were linked to greater differences in siblings' individual characteristics.