Peer network drinking predicts increased alcohol use from adolescence to early adulthood after controlling for genetic and shared environmental selection

Research consistently links adolescents' and young adults' drinking with their peers' alcohol intake. In interpreting this correlation, 2 essential questions are often overlooked. First, which peers are more important, best friends or broader social networks? Second, do peers cause increased drinking, or do young people select friends whose drinking habits match their own? The present study combines social network analyses with family (twin and sibling) designs to answer these questions via data from the National Longitudinal Study of Adolescent Health. Analysis of peer nomination data from 134 schools (n = 82,629) and 1,846 twin and sibling pairs shows that peer network substance use predicts changes in drinking from adolescence into young adult life even after controlling for genetic and shared environmental selection, as well as best friend substance use. This effect was particularly strong for high-intensity friendships. Although the peer-adolescent drinking correlation is partially explained by selection, the present finding offers powerful evidence that peers also cause increased drinking. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

遗传、环境和青少年的吸烟饮酒行为：芬兰双生子研究的回溯与前瞻

本文介绍的两个“芬兰双生子（Finn Twin）”研究是对10个出生组的青少年双生子及其家庭的长期跟踪研究。本文概述了这两个项目对遗传与环境的关联和互动对吸烟饮酒行为影响的研究。这些研究的结果提示个体差异对吸烟饮酒行为的长期变动的影响受到兄弟姐妹互动、同伴互动以及父母教养方式的调节。环境对吸烟饮酒的影响主要表现在学校、居住社区与家庭环境的差异上。环境与遗传影响的程度和持久度有城乡差异。遗传的影响受居住社区的制约。多阶段模型的分析揭示了遗传与环境的互动对这些行为的演变（从试吸试饮到发展到滥用）的动态的影响,遗传似乎对吸烟饮酒的共同轨迹更有影响。这些结果对今后本项目对这约1万对芬兰成年双生子的分子遗传学研究提供了有益的线索     

Adolescents'' alcohol use related to perceived norms

A questionnaire survey was carried out among 898 Norwegian adolescents age twelve to twenty. The study focused on the relation between adolescents' alcohol use on one side and estimated drinking norms (peers' drinking) together with attributed opinion norms (parents' and friends' acceptance of adolescents' alcohol use) on the other. On average, 5% of students in 7th, 8th, and 9th grade reported weekly alcohol use. They overestimated the number of fellow students using alcohol every week seven-fold. Students' estimates were significantly related to self-reported alcohol use. Even in high-school (10th, 11th and 12th grade) where 29% reported weekly alcohol use, students overestimated number of weekly drinkers among friends and fellow students by two-fold. Contrary to the results from a previous study conducted in Norway, in this study opinions attributed to both friends and parents about adolescents' alcohol use were significantly related to the students' own alcohol use. Estimated behavior norms and attributed opinion norms explained 46% of the observed variance in students' self-reported frequency of drinking. In a health promotion context, these results point to the importance of correcting student misconceptions about how often friends and fellow students drink alcohol.     

Parental monitoring moderates the importance of genetic and environmental influences on adolescent smoking

Although there is a substantial literature on the role of parenting in adolescent substance use, most parenting effects have been small in magnitude and studied outside the context of genetically informative designs, raising debate and controversy about the influence that parents have on their children (D. C. Rowe, 1994). Using a genetically informative twin-family design, the authors studied the role of parental monitoring on adolescent smoking at age 14. Although monitoring had only small main effects, consistent with the literature, there were dramatic moderation effects associated with parental monitoring: At high levels of parental monitoring, environmental influences were predominant in the etiology of adolescent smoking, but at low levels of parental monitoring, genetic influences assumed far greater importance. These analyses demonstrate that the etiology of adolescent smoking varies dramatically as a function of parenting.     

Influences of Parental and Best Friends' Smoking and Drinking on Adolescent Use: A Longitudinal Study1

Many studies have dealt with the relative impact of parents and peers on adolescent substance use. However, only a few studies have explored the role of adolescents themselves in social relationships. Homogeneity in behavioral patterns within friendships can also be generated by selective association. Acknowledgment of selection processes might shed new light on the debate on the influences of parents and friends. This paper examines the impact of parental and best friends' smoking and drinking on adolescents' use, using data (N= 1,063) from a 3-wave, 5-year longitudinal study. The results show that friends' smoking did not affect adolescent smoking over time. Only in early adolescence did friends' drinking exert an influence on subjects' alcohol use. On the other hand, parental use had a small but significant impact on their offspring. Furthermore, support was found for processes of selective association.     

Pubertal timing and substance use: associations between and within families across late adolescence

In the present study, between-family analyses of data from adolescent twin girls offer new evidence that early menarche is associated with earlier initiation and greater frequency of smoking and drinking. The role of personality factors and peer relationships in that association was investigated, and little support was found for their involvement. Novel within-family analyses replicating associations of substance use with pubertal timing in contrasts of twin sisters selected for extreme discordance for age at menarche are reported. Within-family replications demonstrated that the association of pubertal timing with substance use cannot be explained solely by between-family confounds. Within-family analyses demonstrated contextual modulation of the influence of pubertal timing: Its impact on drinking frequency is apparent only among girls in urban settings. Sibling comparisons illustrate a promising analytic tool for studying diverse developmental outcomes.     

Alcohol Use in Adolescent Twins and Affiliation with Substance Using Peers

Affiliation with substance using peers is one of the strongest predictors of adolescent alcohol use. This association is typically interpreted causally: peers who drink incite their friends to drink. This association may be complicated by uncontrolled genetic and environmental confounds because teens with familial predispositions for adolescent substance use may be more likely to select into social networks where drinking is common. We test this alternative hypothesis using a sample of 1,820 twin and sibling pairs, and their same-sex best friends, from three waves of the National Longitudinal Study of Adolescent Health. Across all three waves, peer report of substance use did not influence adolescent alcohol use when genetic and shared environmental predispositions for drinking were considered. The association between alcohol use and peer behavior may be a spurious association attributable to a shared genetic liability to drink alcohol and associate with peers who drink alcohol.     

Conjoint developmental trajectories of young adult alcohol and tobacco use

Developmental and etiological advances have set the stage for considering trajectories of problem behavior across the life course, but little work thus far addresses co-occurring problem behavior trajectories. Although recent work characterizes drinking and smoking trajectories, none has explored the course of concurrent drinking and smoking. Using panel data from the Monitoring the Future Project (N=32,087), the authors applied growth mixture modeling to 4 waves of heavy drinking and smoking in a young-adult sample. The authors extracted a single latent group membership factor from heavy drinking and smoking. Associations between trajectory classes and risk factors were relatively unique to the substance being predicted. The association of smoking with alcohol expectancies and delinquency appeared to exist by virtue of smoking's comorbidity with drinking.     

Binge Drinking Among College Athletes and Non-Athletes

Concerns about incidence, forms, and consequences of alcohol use among college students lack examinations of the lifestyles and predictors of college student athletes. This article, using a sample of student-athletes and non-athletes from four Southern universities, identifies the lifestyle predictors for each population, identifying patterns and sets of predictors of binge drinking behavior. Findings indicate that for both samples, binge drinking behavior is explained by sex, drinking in bars, number of male friends who drink, and cigarette smoking. Student-athletes' binge drinking is explained further by residing on campus. Non-athlete binge drinking is related to race and amount of study time per week. Implications for these findings are also discussed.     

Preliminary Evidence for Associations of CHRM2 with Substance Use and Disinhibition in Adolescence

Evidence for shared heritable influences across domains of substance use suggests that some genetic variants influence broad risk for externalizing behaviors. Theories of externalizing psychopathology also suggest that genetic liability for substance use manifests as temperamental risk factors, particularly those related to behavioral disinhibition, during adolescence. The cholinergic muscarinic receptor 2 gene (CHRM2) is a promising candidate for studying genetic influences on broad-based risk for externalizing traits. This study examined a candidate CHRM2 polymorphism (rs1455858) in relation to substance use and personality measures of disinhibition in a sample of high-risk adolescents (n?=?124). Bivariate analyses and structural equation modeling (SEM) evaluated associations of rs1455858 with measures of drug involvement (alcohol, tobacco and marijuana) and disinhibition (indexed by impulsivity and sensation seeking scores). Bivariate analyses showed significant associations of CHRM2 with several behavioral phenotypes. In SEM analyses CHRM2 related significantly to latent measures of substance use and disinhibition; additionally, disinhibition mediated the association of CHRM2 with substance use. These results suggest that CHRM2 variants are potentially relevant for adolescent substance use and that temperamental risk factors could contribute to these associations.     

Adolescents' use of tobacco and alcohol: correlations with habits of parents and friends

Correlations for use of tobacco and alcohol of a Finnish sample of 321 adolescents (164 boys, 157 girls; age range 12-16 years) and those of their mothers, fathers, and best friends showed adolescents' use of both tobacco and alcohol correlated more with use by their friends than with parental use. The r for tobacco smoking was higher with maternal than with paternal smoking.     

How intelligence and education contribute to substance use: Hints from the Minnesota Twin family study

In old and even middle age, there are associations between physical health and both intelligence and education. This may occur because intelligence and/or education exert effects on lifestyle choices that, in turn, affect later health. Substance use is one aspect of lifestyle choice in young adulthood that could play such a role. The effects of intelligence and/or education on substance use could be direct and environmental, or indirect due to the presence of confounding genetic and shared family influences. We used the Minnesota Twin Family Study to distinguish these effects in males and females at age 24. In contrast to prevailing expectations, there were moderately negative direct nonshared environmental effects of both IQ and education on both smoking and drinking in both males and females. That is, controlling for family background effects in the form of both genetic and shared environmental influences, both higher IQ and greater education were associated with greater alcohol and nicotine use. These effects were accounted for by alcohol and nicotine use at age 17. Our results suggest that genetic and family-culture variables confound the associations between intelligence and education and substance use in young adults, rendering them indirect. Further research is needed to understand the roles of IQ and education in alcohol and nicotine use and their relative impacts on physical health throughout the lifespan.     

Self-Control,Opportunity, and Substance Use

We examine the effect of self-control and opportunity on adolescent substance use. When theorizing about the role of opportunity, we believe the “sanction potential” of a given situation should be considered. Our results suggest the effect of self-control on substance use does not depend on the availability of substances in the home (high sanction potential), but friends’ substance use (low sanction potential) conditions the effect of self-control on adolescents’ smoking, drinking, and marijuana use. Therefore, adolescents with low self-control are more likely to use substances only when they are presented with attractive opportunities that are unlikely to lead to sanctions.     

Latent growth curve analyses of peer and parent influences on smoking progression among early adolescents.

Social influences on smoking uptake were examined in latent growth curve analyses of data from 1,320 youths assessed 5 times during 6th to 9th grade. Initial smoking stage predicted increases in number of friends who smoked, indicating selection; however, initial number of friends who smoked did not predict smoking stage progression, indicating no significant effect of socialization. Associations over time among smoking stage progression, affiliation with friends who smoke, and parenting behaviors were significant, suggesting dynamic, reciprocal relationships. Parental involvement, monitoring, and expectations provided direct protective effects against smoking progression as well as indirect effects, by limiting increases in number of friends who smoke. These results are consistent with the peer selection hypothesis, confirm the powerful association over time of social influences with smoking, and provide the first evidence that parenting behavior may protect against smoking progression by limiting increases in number of friends who smoke.     

Do birds of a feather flock together? The variable bases for African American, Asian American, and European American adolescents' selection of similar friends

Variability in adolescent-friend similarity is documented in a diverse sample of African American, Asian American, and European American adolescents. Similarity was greatest for substance use, modest for academic orientations, and low for ethnic identity. Compared with Asian American and European American adolescents, African American adolescents chose friends who were less similar with respect to academic orientation or substance use but more similar with respect to ethnic identity. For all three ethnic groups, personal endorsement of the dimension in question and selection of cross-ethnic-group friends heightened similarity. Similarity was a relative rather than an absolute selection criterion: Adolescents did not choose friends with identical orientations. These findings call for a comprehensive theory of friendship selection sensitive to diversity in adolescents' experiences. Implications for peer influence and self-development are discussed.     

Social contexts of drug offers among American Indian youth and their relationship to substance use: an exploratory study

In this exploratory study the authors examined the social contexts of American Indian youths' encounters with drug offers and their relationship to substance use. Using an inventory of drug use-related problem situations developed specifically for American Indian youth, questionnaires were completed by 71 American Indian youth at public middle schools in a Southwest metropolitan area. Regression analyses highlight the importance of situational and relational contexts in understanding substance use among the youth in this sample. Exposure to drug offers through parents, other adults, cousins, friends and other peers was associated with different types of substance use. Exposure through parents was particularly salient in predicting the drug use of female respondents. The study underscores the need for development of culturally grounded prevention programs in schools, reservations, and nonreservation communities.     

Parental knowledge and adolescent adjustment: substance use and health-related quality of life

This study analyses two models (maternal and paternal) in which parental care and sources of parental knowledge moderated the relationship between parents' knowledge about their adolescents' lives and adolescents' substance use and health-related quality of life. The sample was made up of 15942 Spanish adolescents who participated in the 2006 edition of Health Behavior in School-aged Children Study. Results showed that increased parents' knowledge about their adolescents' lives reduced adolescents' substance use and increased their quality of life. With respect to the moderation relationship, a limited effect was found. However, parental care and sources of parental knowledge used by both parents generally had main effects on adolescents' substance use and health-related quality of life, with care being the most relevant variable in the health-related quality of life, while knowledge was the most relevant one for substance use.     

Body Size Beliefs and Weight Concerns Among Mothers and Their Adolescent Children

African American and White mother/adolescent pairs were examined for familial associations in body size and weight concerns. Mothers' and adolescents' estimates of adolescents' body mass index (BMI) were significantly correlated. Compared to boys, girls had greater body dissatisfaction, higher weight concerns, and perceived higher family/friend weight concerns. By race, White adolescents had more body dissatisfaction and greater concern about weight than African American adolescents. Four items explained 70.4% of the variance in adolescents' weight concern scores: adolescents' weight management practices, mothers' reports of adolescents' saying they were too fat, adolescents' perceptions of family/friends' weight concerns, and adolescents' body dissatisfaction. Our study suggests White girls are more concerned about their weight and perceive greater weight and dieting concerns among family/friends than African American girls.     

The interactive effects of low self-control and commitment to school on substance abuse among college students

This study examined the combined influence of two predicting factors-low self-control and commitment to schooling-that research has shown have independent effects on substance abuse. In a sample of 598 college students, this study tested the interactive effects of these factors while controlling for other established predictors of binge drinking and drug use. Analysis showed that participants who had both low self-control and low schooling commitment had significantly higher scores on substance abuse than would be expected from the independent influences of the component factors, which suggests that the combined effects of these predictors on substance abuse have a greater influence than their direct influences.     

Predicting changes in teenage drug use: the role of intention-behavior discrepancy

This research investigated the role of intention-behavior discrepancy in predicting changes in drug use by American teenagers. The tested behavior included drinking alcohol, smoking cannabis, and taking hard drugs. Data were collected from 1,177 young adolescents at two time points separated by one year. Two sets of analysis were performed--a multitrait-multimethod latent variable model and longitudinal analyses. The results of longitudinal analyses indicated that, although young adolescents were legally and socially prohibited from engaging in drug-taking activities, some of them intended to use drugs. This discrepancy between behaviors and intentions decreased neither drug-taking behaviors nor intentions to use drugs over time; on the contrary, it increased adolescents' illegal drug use and intention to engage in such behaviors as predicted by Brehm's reactance theory. This discrepancy factor was a better predictor of later drug-taking behavior and positive intentions to use drugs than early intentions alone. The best predictor of later behavior and intentions was prior drug use.