Research Review: Siblings matter. A multi-level meta-analysis on the association between cannabis use among adolescent siblings.

BACKGROUND: Parents' and peers' cannabis use are well-documented predictors of youth cannabis use, however, relatively little is known about the influence of siblings' cannabis use. Hence, this meta-analysis investigated the association between sibling-youth cannabis use (disorder) and explored moderation by sibling type (monozygotic- vs. dizygotic- vs. non-twins), age, age spacing, birth order, gender, and gender constellations (same- vs. mix- gender pairs). When comparison data of parents' and peers' cannabis use (disorder) were also available in the included studies, separate meta-analyses on associations between parent-youth and peer-youth cannabis use (disorder) were additionally conducted. METHODS: Studies were selected if they included 11- to 24-year-old participants, and investigated associations between cannabis use (disorder) among those youth and their siblings. These studies were retrieved via a search in seven databases (e.g., PsychINFO). A multi-level meta-analysis using a random effects model was performed on the studies, and heterogeneity analyses and moderator analyses were also conducted. PRISMA guidelines were followed. RESULTS: We retrieved 20 studies (most of which originated from Western cultures) with 127 effect sizes for the main sibling-youth meta-analysis and found a large overall effect-size (r = .423), implying that youth had higher cannabis use rates when their sibling used cannabis, and this association was stronger for monozygotic twins and for same-gender sibling pairs. Finally, a medium effect size existed for the associations between parent-youth cannabis use (r = .300) and a large effect size for peer-youth cannabis use (r = .451). CONCLUSIONS: Youth are more likely to use cannabis when their siblings use cannabis. This sibling-youth cannabis use association existed for all sibling constellations, was larger than the association between parent-youth cannabis use, and was similar in magnitude compared to the association between peer-youth cannabis use-suggesting both genetic and environmental influences (e.g., social-learning) between siblings. Hence, it is important not to neglect sibling influences when treating youth cannabis use (disorder).

A cross-national study on adolescent substance use: Intentions, peer substance use, and parent-adolescent communication.

This longitudinal two-wave cross-national study investigated whether intentions, friends' substance use, and parent-adolescent substance-use specific communication predict adolescent alcohol and cannabis use 1 year later, while estimating reversed links. The temporal order between these two substances was also examined. We used multi-group cross-lagged panel modeling on data from 2 ethnically and socioeconomically diverse samples: Sint Maarten (N = 350; Mage  = 14.19) and the Netherlands (N = 602; Mage  = 13.50). Results showed that in the Netherlands, cannabis use predicts more subsequent problems (alcohol use, intention to use cannabis, and affiliation with cannabis-using friends). But for Sint Maarten, alcohol use predicts more subsequent problems (cannabis use, intention to use alcohol, and affiliation with alcohol-using friends). These opposing results demonstrate that caution is warranted when generalizing results across countries.

Adolescents' own views on their risk behaviors, and the potential effects of being labeled as risk-takers: A commentary and review.

Adolescents are stereotypically viewed as risk-takers ("stereotypical risk-takers") in science, mainstream media, fictional literature and in everyday life. However, increasing research suggests that adolescents do not always engage in "heightened" risk-taking, and adolescents' own perspectives (motives) on risk-taking are largely neglected in research. Hence, this paper is a commentary and review with two aims. First, taking a cross-national perspective, we discuss the definition of adolescence and risk behavior. We argue that much of the research on what drives adolescent risk behavior (e.g., substance use) focuses on the harms that this behavior promotes rather than on the need to explore and grow into adulthood. Thereafter we summarize the dominant approach to studying motives behind substance use, which has mostly considered young adults, and which has typically not focused on adolescents' own self-generated motives. The few empirical studies (including one of our qualitative studies) on adolescents' own motivations for engaging in risk behavior (i.e., cannabis use, alcohol use, and tobacco smoking) show that the most frequently mentioned motives by adolescents were being cool/tough, enjoyment, belonging, having fun and experimenting and coping. Interestingly, the "cool/tough identity" motive is virtually overlooked in research on adolescent risk-taking. The above-mentioned motives, however, generally support newer theories, such as the Developmental Neuro-Ecological Risk-taking Model (DNERM) and the Life-span Wisdom Model that suggest that adolescents' motivations to engage in risk-taking include experimentation, identity development, explorative behavior, and sensation seeking, all of which run counter to the stereotype of adolescents engaging in risk-taking due to "storm and stress." Hence, we also briefly consider additional recent attempts to study positive forms of risk taking. Second, extrapolating from sociological/criminological theories on labeling, we suggest that caution is warranted when (inaccurately) labeling adolescents as the "stereotypical risk-takers," because this can instigate a risk-taking identity in adolescents and/or motivate them to associate with risk-taking peers, which could in turn lead to maladaptive forms of risk-taking. Empirical research testing these hypotheses is needed. To conclude we argue that research on adolescent risk-taking could further benefit from considering adolescent's own motivations, which is also in line with the participatory approach advocated by international children's rights standards.

Cascades From Early Adolescent Impulsivity to Late Adolescent Antisocial Personality Disorder and Alcohol Use Disorder.

PURPOSE: The behavioral disinhibition model (BDM) posits that a liability toward impulsivity evident by early adolescence underlies the coemergence of antisocial behavior and alcohol use (i.e., problem behaviors) in early-adolescence to mid-adolescence, but that the subsequent development of these problem behaviors (rather than impulsivity itself) predicts the emergence of antisocial personality disorder (APD) and alcohol use disorder (AUD) in late adolescence. The present study was designed to test these predictions of the BDM from early to late adolescence. METHODS: We used five-year longitudinal self-report data from the Philadelphia Trajectory Study that was collected from 2006-2012. Mediational analyses were performed using the Random Intercept Cross-lagged Panel Model, which enables the detection of within-person predictions of changes in problem behaviors during adolescence. The sample was ethnically and socioeconomically diverse, including 364 urban US community youth (at baseline: Mage = 13.51(.95); 49.1% female). RESULTS: Consistent with the BDM, mediational analyses revealed that changes in early adolescent impulsivity predicted late adolescent APD and AUD criteria, mediated by changes in mid-adolescent alcohol use and conduct problems. DISCUSSION: Interventions targeting impulsivity in early adolescence could potentially halt the cascading chain of events leading to both late adolescent APD and AUD by decelerating growth in antisocial behavior and alcohol use during early-adolescence to mid-adolescence. From mid-adolescence to late-adolescence, the consequences of early impulsivity, especially involvement in antisocial behaviors, become a more relevant predictor of both APD and AUD rather than impulsivity itself.

The Co-development of Friends' Delinquency with Adolescents' Delinquency and Short-term Mindsets: The Moderating Role of Co-Offending.

The companions in crime hypothesis suggests that co-offending moderates the link between peer delinquency and adolescent delinquency. However, this hypothesis has rarely been investigated longitudinally. Hence, this study investigated the co-development of friends' delinquency and adolescents' delinquency, as well as the co-development of friends' delinquency and short-term mindsets (impulsivity and lack of school future orientation). Whether this co-development is stronger when adolescents engage in co-offending was also investigated. Three data waves with two year lags from an ethnically-diverse adolescent sample (at wave 1: N = 1365; 48.6% female; Mage = 13.67; age range = 12.33-15.09 years) in Switzerland were used. The results from parallel process latent growth modeling showed that the co-development between friends' delinquency and adolescents' delinquency was stronger when adolescents engaged in co-offending. Thus co-offending likely provides direct access to a setting in which adolescents continue to model the delinquency they learned with their peers.

Is the Peer Presence Effect on Heightened Adolescent Risky Decision-Making only Present in Males?

Social neurodevelopmental imbalance models posit that peer presence causes heightened adolescent risk-taking particularly during early adolescence. Evolutionary theory suggests that these effects would be most pronounced in males. However, the small but growing number of experimental studies on peer presence effects in adolescent risky decision-making showed mixed findings, and the vast majority of such studies did not test for the above-described gender and adolescent phase moderation effects. Moreover, most of those studies did not assess the criterion validity of the employed risky decision-making tasks. The current study was designed to investigate the abovementioned hypotheses among a sample of 327 ethnically-diverse Dutch early and mid-adolescents (49.80% female; Mage = 13.61). No main effect of peer presence on the employed risky-decision making task (i.e., the stoplight game) was found. However, the results showed a gender by peer presence moderation effect. Namely, whereas boys and girls engaged in equal levels of risks when they completed the stoplight game alone, boys engaged in more risk-taking than girls when they completed this task together with two same-sex peers. In contrast, adolescent phase did not moderate peer presence effects on risk-taking. Finally, the results showed that performance on the stoplight game predicted self-reported real-world risky traffic behavior, alcohol use and delinquency. Taken together, using a validated task, the present findings demonstrate that individual differences (i.e., gender) can determine whether the social environment (i.e., peer presence) affect risk-taking in early- and mid-adolescents. The finding that performance on a laboratory risky decision-making task can perhaps help identify adolescents that are vulnerable to diverse types of heightened risk behaviors is an important finding for science as well as prevention and intervention efforts.

Disentangling longitudinal relations between youth cannabis use, peer cannabis use, and conduct problems: developmental cascading links to cannabis use disorder.

AIMS: To determine whether cannabis use during adolescence can increase risk not only for cannabis use disorder (CUD) but also for conduct problems, potentially mediated by exposure to peers who use cannabis. DESIGN, SETTING, PARTICIPANTS: Longitudinal study analyzing four waves of longitudinal data from 364 racially and socio-economically diverse, urban, US community youth (at baseline: Mage  = 13.51 (0.95); 49.1% female). MEASUREMENTS: Self-reports of cannabis use, conduct problems, proportion of peers using cannabis and CUD criteria at the final wave were analyzed using a method sensitive to changes over development, the random-intercept cross-lagged panel model. FINDINGS: Change in cannabis use did not predict changes in conduct problems or peer cannabis use over time, controlling for gender, race-ethnicity and socio-economic status. Instead, increases in conduct problems predicted increases in cannabis use and ultimately CUD, with some of the effect mediated by increases in the prevalence of peer cannabis use [ß = 0.12, 95% confidence interval (CI) = 0.07, 0.20]. Additionally, affiliation with peers who used cannabis predicted subsequent CUD via increased personal cannabis use (ß = 0.08, 95% CI = 0.04, 0.14). Significant within-person betas for the cross-lagged effects ranged between 0.20 and 0.27. CONCLUSIONS: Cannabis use in adolescence does not appear to lead to greater conduct problems or association with cannabis-using peers apart from pre-existing conduct problems. Instead, adolescents who (1) increasingly affiliate with cannabis-using peers or (2) have increasing levels of conduct problems are more likely to use cannabis, and this cascading chain of events appears to predict cannabis use disorder in emerging adulthood.

The Relative Roles of Peer and Parent Predictors in Minor Adolescent Delinquency: Exploring Gender and Adolescent Phase Differences.

Social learning theories assume that delinquent peer norms and/or peer pressure are the components of delinquent peer socialization that lead to subsequent adolescent delinquency. However, these specific peer influences are rarely investigated. Moreover, social learning theories such as coercion theory posit that parenting behaviors also play an important role in the development or prevention of delinquency. However, surprisingly, little research has investigated whether parent behaviors could moderate the link between the above-described peer influences and adolescent delinquency. Hence, using structural equation modeling, the current 1-year longitudinal study investigated these questions among ethnically-diverse Dutch adolescents (N = 602; M age = 13.50; 46.42% female at baseline), who were mostly between12 and 15 years old. Additionally, using multi-group models, and a stringent p-value of p < 0.01, we explored whether gender and adolescent phase (i.e., early versus middle adolescence) further moderated these links. The majority of the analyses, resulted in non-significant findings. Specifically, in our non-multi group model, we found no significant peer, and family effects for the entire sample. However, for our multi-group models, we found that higher levels of negative mother-adolescent relationship quality exacerbated the link between peer pressure and subsequent early adolescent boys' delinquency 1 year later, while low levels of mother-adolescent negative relationship quality reversed the association. That is, low levels of mother-adolescent negative relationship quality attenuated the link from higher levels of peer pressure to higher levels of delinquency, but only in early adolescent boys. These findings existed above and beyond significant links from prior adolescent delinquency (T1) to future adolescent delinquency (T2). To conclude, although this was not the case for most adolescents, for early adolescent boys fewer negative interactions between mother and adolescents at an earlier time point (in advance) could potentially curtail the negative effects that delinquent peer pressure has on delinquency in the future. Implications for theory and practice are discussed.

The unique roles of intrapersonal and social factors in adolescent smoking development.

Adolescence is a vulnerable period for the initiation and peak of many harmful risk-taking behaviors such as smoking, which is among the most addictive and deadliest behaviors. Generic metatheories like the theory of triadic influence (TTI) suggest that interrelated risk factors across multiple domains (i.e., intrapersonal and social/environmental) jointly contribute to adolescent smoking behavior. Yet, studies are lacking that investigate risk factors across different domains in the same study, which obscures whether each makes a unique contribution to the increase in smoking throughout adolescence or whether there is overlap across the domains. Hence, to fill this gap using a latent growth approach, the current accelerated longitudinal study investigated the collective contribution of multiple intrapersonal and social risk factors in the development of smoking behavior from ages 12 to 17 in 574 ethnically diverse Dutch adolescents. Results from the latent growth model showed that whereas the contribution of motivational-intrapersonal factors like sensation-seeking was no longer significant in the stringent multivariate model, higher levels of impulsivity (cognitive-intrapersonal) and overt peer pressure (social) at age 12 proved to be robust and unique predictors of linear increases in adolescent smoking up until age 17. Consistent with the TTI, adolescent smoking progression does not occur in isolation and the determinants are wide-ranging as they stem from both intrapersonal and social domains. Thus focusing on such confluence of intrapersonal and social risk factors via prevention programs from as young as age 12 might halt the deadly increase in smoking behavior throughout adolescence. (PsycINFO Database Record

A meta-analysis on age differences in risky decision making: adolescents versus children and adults.

Despite evident heightened adolescent risk-taking in real-life situations, not all experimental studies demonstrate that adolescents take more risks than children and adults on risky decision-making tasks. In the current 4 independent meta-analyses, neurodevelopmental imbalance models and fuzzy trace theory were used as conceptual frameworks to examine whether adolescents engage in more risk-taking than children and adults and whether early adolescents take more risks than children and mid-late adolescents on behavioral risk-taking tasks. Studies with at least 1 of the aforementioned age comparisons met the inclusion criteria. Consistent with imbalance models and fuzzy trace theory, results from a random-effects model showed that adolescents take more risks (g = .37) than adults, and early adolescents take more risks (g = .15) than mid-late adolescents. However, inconsistent with both perspectives, adolescents and children take equal levels of risk (g = -.00), and early adolescents and children also take equal levels of risk (g = .04). Meta-regression analyses revealed that, consistent with imbalance models, (a) adolescents take more risks than adults on hot tasks with immediate outcome feedback on rewards and losses; however, contrary to imbalance models but consistent with fuzzy trace theory, (b) adolescents take fewer risks than children on tasks with a sure/safe option. Shortcomings related to studies using behavioral risk-taking tasks are discussed. We suggest a hybrid developmental neuroecological model of risk-taking that includes a risk opportunity component to explain why adolescents take more risks than children in the real world but equal levels of risks as children in the laboratory.

Siblings versus parents and friends: longitudinal linkages to adolescent externalizing problems.

BACKGROUND: It is well documented that friends' externalizing problems and negative parent-child interactions predict externalizing problems in adolescence, but relatively little is known about the role of siblings. This four-wave, multi-informant study investigated linkages of siblings' externalizing problems and sibling-adolescent negative interactions on adolescents' externalizing problems, while examining and controlling for similar linkages with friends and parents. METHODS: Questionnaire data on externalizing problems and negative interactions were annually collected from 497 Dutch adolescents (M = 13.03 years, SD = 0.52, at baseline), as well as their siblings, mothers, fathers, and friends. RESULTS: Cross-lagged panel analyses revealed modest unique longitudinal paths from sibling externalizing problems to adolescent externalizing problems, for male and female adolescents, and for same-sex and mixed-sex sibling dyads, but only from older to younger siblings. Moreover, these paths were above and beyond significant paths from mother-adolescent negative interaction and friend externalizing problems to adolescent externalizing problems, 1 year later. No cross-lagged paths existed between sibling-adolescent negative interaction and adolescent externalizing problems. CONCLUSIONS: Taken together, it appears that especially older sibling externalizing problems may be a unique social risk factor for adolescent externalizing problems, equal in strength to significant parents' and friends' risk factors.