Testing Cross-Generational Effects of the Raising Healthy Children Intervention on Young Adult Offspring of Intervention Participants.

This study tested whether effects of a preventive intervention delivered in elementary school showed benefits for the young adult offspring of intervention recipients over 20 years later. The Raising Healthy Children (RHC) intervention, trialed in 18 public schools in Seattle, Washington, from 1980-1986 (grades 1-6), sought to build strong bonds to family and school to promote school success and avoidance of substance use and illegal behavior. Four intervention groups were constituted: full, late, parent training only, and control. Participants were followed through 2014 (age 39 years). Those who became parents were enrolled in an intergenerational study along with their oldest offspring (10 assessments between 2002 and 2018). This study includes young adult offspring (ages 18-25 years; n = 169; 52% female; 4% Asian, 25% Black, 40% multiracial, 4% Native American, 2% Native Hawaiian/Pacific Islander, 25% White, and 14% Hispanic/Latinx) of participants in the original RHC trial. Offspring outcome measures included high school noncompletion, financial functioning, alcohol misuse, cannabis misuse, cigarette use, criminal behavior, internalizing behavior, social skills, and social bonding. A global test across all young adult outcome measures showed that offspring of parents who received the full RHC intervention reported better overall functioning compared to offspring of control group parents. Analyses of individual outcomes showed that offspring of full intervention group parents reported better financial functioning than offspring of control group parents. Findings show the potential of universal preventive interventions to provide long-term benefits that reach into the next generation. ClinicalTrials.gov Identifier: NCT04075019; retrospectively registered in 2019.

Substance use prevention during adolescence: Study protocol for a large-scale cluster randomized trial of Botvin High School LifeSkills Training.

BACKGROUND: Concerns about the rise in adolescent vaping and cannabis use suggest the need for effective substance use prevention programs. Botvin LifeSkills Training (LST) has a strong evidence base at the middle school level for preventing or reducing tobacco use and related problems. A high school (grades 9-10) version of the LST program was also developed and shows promising initial evidence for reducing tobacco use in a single pilot study. However, the high school version of LST has not been sufficiently tested in an experimental trial, despite being widely implemented in high schools across the U.S. This paper outlines the study protocol for a large-scale cluster randomized trial of Botvin High School LST, with objectives of documenting the design of prospective research and promoting transparency. METHODS: A total of 60 high schools in Colorado and Ohio were randomized to the 10-session, teacher-led intervention group (n = 33 schools) or business-as-usual control group (n = 27 schools). Across two cohorts of schools, 9th-grade students complete self-report surveys at pretest, immediate posttest, 1-year follow-up, and 21-month follow-up. Primary outcomes are tobacco (nicotine) use and cannabis use. Secondary outcomes are alcohol use, illicit drug use, psychosocial behaviors (e.g., violence and mental health), and academic achievement. Intent-to-treat analyses will use multilevel modeling to estimate intervention effects across assessment points. CONCLUSION: This independent evaluation will help to determine whether the intervention is appropriate for large-scale adoption. This trial is preregistered with the Open Science Framework (https://osf.io/dnz5q/).

Associations of attention problems and family context in childhood and adolescence with young adult daily smoking: General and smoking-specific family contexts.

BACKGROUND: The potential heterogeneity in daily smoking across young adulthood has been relatively understudied. Relatedly, the unique and joint associations of earlier risk factors with young adults' daily smoking largely remain unknown. To address these gaps, this work identified subgroups of daily smoking trajectories during young adulthood and linked them to earlier attention problems and smoking-specific and general family context. METHODS: Data came from the Seattle Social Development Project, a longitudinal study following a community sample (N = 808). Participants' daily smoking was measured from ages 21-33. Earlier attention problems were assessed at ages 14-16 and 18. Earlier smoking-specific and general family factors were assessed at ages 10-16 and 18. RESULTS: Growth mixture models produced four profiles: chronic daily smokers, increasers, decreasers, and no-daily smokers. Results from multinomial logistic regressions revealed that earlier attention problems and smoking-specific family factors may contribute to daily smoking in the early 20 s, whereas earlier general family context provided protection for trajectories of daily smoking characterized by changes in the late 20 s and early 30 s DISCUSSION: Selective prevention strategies that expand people's repertoire of healthy options to address attention problems might be helpful, considering the possibility of using tobacco as means to mitigate attention problems. Our findings also highlight the importance of nurturing earlier general family context, a relatively overlooked dimension in smoking prevention efforts, to facilitate young adult smokers' desistence from daily smoking, particularly those who have attention problems in adolescence.

Longitudinal associations between flavored tobacco use and tobacco product cessation in a national sample of adults.

Use of flavored tobacco has been associated with lower likelihood of short-term abstinence from tobacco. It is unknown whether longer-term associations exist, particularly for a variety of products and specific flavor categories. This study used adult survey data from the Population Assessment of Tobacco and Health (PATH) Study (2013-2018). We tested associations of past 30-day tobacco product use at wave 2 using both a 2-category any flavor versus unflavored variable and 4-category specific flavor (menthol/mint, sweet, and both menthol/mint and sweet) versus unflavored variable with past 12-month cessation from the same product two years later at wave 4. Separate models were run for each product (combustible cigarettes, cigars, hookah, e-cigarettes, and smokeless), adjusting for wave 1 sociodemographic characteristics. For all five products, past 30-day use of any flavored (versus unflavored) product at wave 2 was associated with reduced likelihood of same-product cessation at wave 4. Most specific flavor categories were associated with reduced odds of same-product cessation across all products. Any flavor use was also associated with reduced likelihood of longer-term cessation (i.e., past 24-months at both waves 3 and 4) and cessation from all five tobacco products in several analyses. Exploratory moderation results indicated that the association between e-cigarette flavor use and lower likelihood of cessation was stronger for young adults (18-24) versus older adults (25+). Current use of flavored tobacco products is associated with lower likelihood of product cessation. Flavored tobacco products warrant consideration in regulatory policy to reduce the adverse public health impact of tobacco use.

The Role of Clearinghouses in Promoting Transparent Research: A Methodological Study of Transparency Practices for Preventive Interventions.

Transparency of research methods is vital to science, though incentives are variable, with only some journals and funders adopting transparency policies. Clearinghouses are also important stakeholders; however, to date none have implemented formal procedures that facilitate transparent research. Using data from the longest standing clearinghouse, we examine transparency practices for preventive interventions to explore the role of online clearinghouses in incentivizing researchers to make their research more transparent. We conducted a descriptive analysis of 88 evaluation reports reviewed in 2018-2019 by Blueprints for Healthy Youth Development, when the clearinghouse began checking for trial registrations, and expanded on these efforts by applying broader transparency standards to interventions eligible for an endorsement on the Blueprints website during the study period. Reports were recent, with 84% published between 2010 and 2019. We found that few reports had data, code, or research materials that were publicly available. Meanwhile, 40% had protocols that were registered, but only 8% were registered prospectively, while one-quarter were registered before conducting analyses. About one-third included details in a registered protocol describing the treatment contrast and planned inclusions, and less than 5% had a registered statistical analysis plan (e.g., planned analytical methods, pre-specified covariates). Confirmatory research was distinguished from exploratory work in roughly 40% of reports. Reports published more recently (after 2015) had higher rates of transparency. Preventive intervention research needs to be more transparent. Since clearinghouses rely on robust findings to make well-informed decisions and researchers are incentivized to meet clearinghouse standards, clearinghouses should consider policies that encourage transparency to improve the credibility of evidence-based interventions.

Common Methodological Problems in Randomized Controlled Trials of Preventive Interventions.

Randomized controlled trials (RCTs) are often considered the gold standard in evaluating whether intervention results are in line with causal claims of beneficial effects. However, given that poor design and incorrect analysis may lead to biased outcomes, simply employing an RCT is not enough to say an intervention "works." This paper applies a subset of the Society for Prevention Research (SPR) Standards of Evidence for Efficacy, Effectiveness, and Scale-up Research, with a focus on internal validity (making causal inferences) to determine the degree to which RCTs of preventive interventions are well-designed and analyzed, and whether authors provide a clear description of the methods used to report their study findings. We conducted a descriptive analysis of 851 RCTs published from 2010 to 2020 and reviewed by the Blueprints for Healthy Youth Development web-based registry of scientifically proven and scalable interventions. We used Blueprints' evaluation criteria that correspond to a subset of SPR's standards of evidence. Only 22% of the sample satisfied important criteria for minimizing biases that threaten internal validity. Overall, we identified an average of 1-2 methodological weaknesses per RCT. The most frequent sources of bias were problems related to baseline non-equivalence (i.e., differences between conditions at randomization) or differential attrition (i.e., differences between completers versus attritors or differences between study conditions that may compromise the randomization). Additionally, over half the sample (51%) had missing or incomplete tests to rule out these potential sources of bias. Most preventive intervention RCTs need improvement in rigor to permit causal inference claims that an intervention is effective. Researchers also must improve reporting of methods and results to fully assess methodological quality. These advancements will increase the usefulness of preventive interventions by ensuring the credibility and usability of RCT findings.

Associations between self-reported cannabis use frequency, potency, and cannabis/health metrics.

BACKGROUND: Research shows that cannabis use frequency is associated with cannabis dependence and health metrics. However, much less is known about how self-reported cannabis potency (THC and CBD) may be associated with the same metrics, and whether any associations exist after accounting for frequency of cannabis use. Moreover, even less is known about how these relations may differ across cannabis product forms. This exploratory study examined 1) associations between cannabis frequency, potency, and cannabis/health metrics, and 2) whether associations between potency and cannabis/health metrics remained after controlling for frequency of use. METHODS: Using a sample of adult recreational cannabis users in Colorado (N = 300), we tested the relationship between self-reported cannabis use metrics of frequency and potency of flower, edible, and concentrate products with separate measures of problematic cannabis use (i.e., dependence, withdrawal, craving), depression, anxiety, and general perceived health. RESULTS: Greater frequency of flower and concentrate (but not edible) use were associated with greater problematic cannabis use, and greater concentrate use frequency was also associated with more mental health problems. Partial correlations controlling for average frequency of use across all product forms and CBD potency per product showed that one significant association between THC potency and cannabis/health metrics remained (i.e., higher THC concentrate potency with better health), and one emerged (i.e., higher THC concentrate potency with lower cannabis withdrawal). CONCLUSIONS: Frequency of use is reliably associated with problematic cannabis use for flower and concentrates, but it did not account for all observed associations in this study. Differences in patterns of associations between frequency and potency and cannabis/health metrics across cannabis forms suggest a need for better understanding user reports of THC and CBD potency, individual differences among users, and improved measurement.

Outcomes of Childhood Preventive Intervention Across 2 Generations: A Nonrandomized Controlled Trial.

Importance: Trials of preventive interventions for children that were implemented in the 1980s have reported sustained positive outcomes on behavioral and health outcomes into adulthood, years after the end of the intervention. This present study examines whether intervention in childhood may show sustained benefits across generations. Objective: To examine possible intervention outcomes on the offspring of individuals (now parents) who participated in the Raising Healthy Children preventive intervention as children in the elementary grades. Design, Setting, and Participants: This nonrandomized controlled trial was conducted in public elementary schools serving high-crime areas in Seattle, Washington. The panel originated in Seattle but was followed up locally and in out-of-state locations over time. Data analyzed in this study were collected from September 1980 to June 2011, with follow-up of the firstborn offspring (aged 1 through 22 years) of 182 parents who had been in the full intervention vs control conditions in childhood. Their children were assessed across 7 waves in 2 blocks (2002-2006 and 2009-2011). Data were analyzed for this article from September 2018 through January 2019. Interventions: In grades 1 through 6, the Raising Healthy Children intervention provided elementary school teachers with methods of classroom management and instruction, first-generation (G1) parents with skills to promote opportunities for children's active involvement in the classroom and family, and second-generation (G2) child with social and emotional skills training. Main Outcomes and Measures: Outcomes examined in the third-generation (G3) offspring were self-regulation (emotion, attention, and behavioral regulation), cognitive capabilities, and social capabilities. Risk behaviors, including substance use and delinquency, were examined from age 6 years to study completion. Early onset of sexual activity was examined from age 13 years to study completion. Intent-to-treat analyses controlled for potential confounding factors. Results: A total of 182 G3 children were included in this analysis (72 in the full intervention and 110 in the control condition; mean age at first wave of data collection, 7 [range, 1-13] years). Significant differences in the offspring of intervention parents were observed across 4 domains: improved early child developmental functioning (ages 1-5 years; significant standardized ß range, 0.45-0.56), lower teacher-rated behavioral problems (ages 6-18 years; significant standardized ß range, -0.39 to -0.46), higher teacher-rated academic skills and performance (ages 6-18 years; significant standardized ß range, 0.34-0.49), and lower child-reported risk behavior (ages 6-18 years; odds ratio for any drug use [alcohol, cigarettes, or marijuana], 0.27 [95% CI, 0.10-0.73]). Conclusions and Relevance: To our knowledge, this is the first study to report significant intervention differences in the offspring of participants in a universal childhood preventive intervention. Cost-benefit analyses have examined the benefits of childhood intervention in the target generation. The present study suggests that additional benefits can be realized in the next generation as well. Trial Registration: ClinicalTrials.gov Identifier: NCT04075019.

An intergenerational investigation of the associations between parental marijuana use trajectories and child functioning.

Diverse patterns of life-course marijuana use may have differential health impacts for the children of users. Data are drawn from an intergenerational study of 426 families that included a parent, their oldest biological child, and (where appropriate) another caregiver who were interviewed 10 times from 2002 to 2018; the current study used data from 380 families in waves 6-10. Analyses linked parent marijuana use trajectories estimated in a previous publication (Epstein et al., 2015) to child marijuana, alcohol, and nicotine use; promarijuana norms; internalizing; externalizing; attention problems; and grades using multilevel modeling among children ages 6 to 21. Four trajectories had been found in the previous study: nonuser, chronic, adolescent-limited, and late-onset. Results indicate that children of parents in the groups that initiated marijuana use in adolescence (chronic and adolescent-limited) were most likely to use substances. Children of parents in the late-onset group, where parents initiated use in young adulthood, were not at increased risk for substance use but were more likely to have attention problems and lower grades. Results held when parent current marijuana use was added to the models. Implications of this work highlight the importance of considering both current use and use history in intergenerational transmission of marijuana use, and the need to address parent use history in family based prevention. Prevention of adolescent marijuana use remains a priority. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Time-varying effects of family smoking and family management on adolescent daily smoking: The moderating roles of behavioral disinhibition and anxiety.

BACKGROUND: Family smoking environment and family management are associated with risk of teen smoking behaviors. However, less is known about whether these associations increase or decrease in strength across adolescence, and whether there are person-environment interactions. The current study examined 1) the age-varying main effects of family smoking and family management on adolescent daily smoking from ages 12-18 and tested 2) whether behavioral disinhibition and anxiety moderated these relationships. METHODS: Data were drawn from the Seattle Social Development Project (SSDP; N = 808), a longitudinal study examining prosocial and antisocial behavior. Analyses used time-varying effect modeling (TVEM), which tested the stability of the relationship between family smoking and family management and youth daily smoking across adolescence. RESULTS: Greater family smoking increased the likelihood of adolescent daily smoking, whereas greater family management reduced the likelihood of daily smoking. Significant interactions between family management and youth behavioral disinhibition and anxiety during early and mid-adolescence indicated that family management was more protective for adolescents with low (compared to high) behavioral disinhibition and anxiety. The effect of family smoking was not moderated by behavioral disinhibition or anxiety. CONCLUSIONS: Family smoking and family management are key risk and protective factors that may be targeted for adolescent smoking prevention. Our interaction results for individual differences in behavioral disinhibition and anxiety suggest that certain types of youth may respond differently to family management practices. Findings also show periods during adolescence where family-centered preventive interventions could be optimally timed to prevent or reduce persistent adolescent smoking.

The link between parental smoking and youth externalizing behaviors: Effects of smoking, psychosocial factors, and family characteristics.

This study examined the associations between parental cigarette smoking and youth externalizing behaviors (i.e., oppositional and conduct problems) both concurrently and 1 year later, and tested whether parental smoking predicted youth externalizing over and above parent psychosocial, family, and demographic characteristics linked to smoking and externalizing behaviors. Data were drawn from the Seattle Social Development Project (SSDP) and The Intergenerational Project (TIP), a prospective longitudinal study aimed toward understanding the intergenerational transmission of substance use, mental health, and risky behaviors. The current study used multilevel modeling to examine both concurrent and lagged associations from 325 families, which included parents and youth (Aged 6-19) across seven waves of data. In concurrent analyses, both parental smoking and several family characteristics independently predicted higher levels of child externalizing behaviors, even after controlling for parent age at child birth and demographic correlates of smoking. However, parental depressive symptoms reduced the association between smoking and externalizing behaviors to nonsignificance in concurrent models. In lagged analyses, only harsh parenting, low monitoring, and low parent-child bonding predicted externalizing behaviors 1 year later; parental smoking did not predict externalizing behaviors over time. Results showed that parental smoking, mental health, parenting, and family relationships all are associated with externalizing problems and constitute potential intervention targets in the short term, though poor parenting and parent-child bonding, rather than smoking, predicted externalizing behaviors over time. The robust association between concurrent parental depressive symptoms and youth conduct problems may suggest prioritizing parental mental health (e.g., via mental health screening) for improving both parent and child well-being. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Adolescent Age of Sexual Initiation and Subsequent Adult Health Outcomes.

OBJECTIVES: To examine the mechanisms of the association between age of sexual initiation and adult health. METHODS: Data from the Seattle Social Development Project (n = 808), in Seattle, Washington, included outcomes when participants were in their 30s (2005-2014): substance use disorders, depression, poor health, and obesity. Sexual consequence mediators included sexually transmitted infection, adolescent pregnancy, and a high number of sexual partners. We used linear logistic regression to model main effect and mediated associations. RESULTS: Age of sexual initiation was related to nicotine and marijuana disorders, physical health, and obesity, but not alcohol disorder or depression. Mediated association with nicotine disorder was not significant; association with marijuana disorder was reduced; significant relationships with poor health and obesity remained. CONCLUSIONS: The relationship between age of sexual initiation and substance use was largely explained by consequences of sexual behavior. Earlier sexual initiation was linked to poorer physical health outcomes, though the nature of the association remains unclear. Public Health Implications. Prevention approaches need to address multiple risk factors and emphasize contraceptive methods to avoid sexual consequences. For physical health outcomes, broad prevention approaches, including addressing early sexual initiation, may be effective.

Concurrent and Prospective Associations Between Substance-Specific Parenting Practices and Child Cigarette, Alcohol, and Marijuana Use.

PURPOSE: The current study aimed to understand whether substance-specific parenting practices predicted the probability of child alcohol, cigarette, or marijuana use beyond known family factors like family management and parental substance use and norms. METHODS: Data were drawn from the Intergenerational Project, which used an accelerated longitudinal design and included 383 families surveyed seven times between 2002 and 2011. Analyses included 224 families with children ages 10-18 years (49% female). Multilevel models tested both concurrent and lagged (predictors at time t - 1, outcomes at time t) associations between child past year use of alcohol, cigarettes, and marijuana and time-varying measures of substance-specific parenting practices, including permitting child use of alcohol or cigarettes; family rules about alcohol, cigarette, and drug use; and child involvement in family member alcohol or cigarette use (getting, opening, or pouring alcoholic drinks; getting or lighting cigarettes for family members). Demographic controls were included. RESULTS: Child involvement in family member substance use predicted an increased probability of child substance use both concurrently and 1 year later, even when controlling parent substance use, pro-substance norms, and family management. Family rules about substance use and parent provision of alcohol or cigarettes were not consistently related to child alcohol, cigarette, or marijuana use. CONCLUSIONS: Family-based preventive interventions to reduce youth substance use should continue to focus on family management and include messaging discouraging parents from allowing children to get, open, or pour drinks or get or light cigarettes for family members.

Predictors of Adult Marijuana Use Among Parents and Nonparents.

The current study examined predictors of marijuana use among adults, including subsamples of adults who are actively parenting (i.e., have regular face-to-face contact with a child) and those who have no children. Participants were a community sample of 808 adults and two subsamples drawn from the full group: 383 adults who were actively parenting and 135 who had no children. Multilevel models examined predictors of marijuana use in these three groups from ages 27 to 39. Becoming a parent was associated with a decrease in marijuana use. Regular marijuana use in young adulthood (ages 21-24), partner marijuana use, and pro-marijuana attitudes increased the likelihood of past-year marijuana use among all participants. Being a primary caregiver (among parents) was associated with less marijuana use. Overall, predictors of marijuana use were similar for all adults, regardless of parenting status. Study results suggest that the onset of parenthood alone may be insufficient to reduce adult marijuana use. Instead, preventive intervention targets may include changing adult pro-marijuana attitudes and addressing marijuana use behaviors of live-in partners. Lastly, universal approaches targeting parents and nonparents may be effective for general adult samples.

The Relationship Between Marijuana and Conventional Cigarette Smoking Behavior from Early Adolescence to Adulthood.

Longitudinal analyses investigated (a) the co-occurrence of marijuana use and conventional cigarette smoking within time and (b) bidirectional associations between marijuana and conventional cigarette use in three developmental periods: adolescence, young adulthood, and adulthood. A cross-lag model was used to examine the bidirectional model of marijuana and conventional cigarette smoking frequency from ages 13 to 33 years. The bidirectional model accounted for gender, school-age economic disadvantage, childhood attention problems, and race. Marijuana use and conventional cigarette smoking were associated within time in decreasing magnitude and increased cigarette smoking predicted increased marijuana use during adolescence. A reciprocal relationship was found in the transition from young adulthood to adulthood, such that increased conventional cigarette smoking at age 24 years uniquely predicted increased marijuana use at age 27 years, and increased marijuana use at age 24 years uniquely predicted more frequent conventional cigarette smoking at age 27 years, even after accounting for other factors. The association between marijuana and cigarette smoking was found to developmentally vary in the current study. Results suggest that conventional cigarette smoking prevention efforts in adolescence and young adulthood could potentially lower the public health impact of both conventional cigarette smoking and marijuana use. Findings point to the importance of universal conventional cigarette smoking prevention efforts among adolescents as a way to decrease later marijuana use and suggest that a prevention effort focused on young adults as they transition to adulthood would lower the use of both cigarette and marijuana use.

Placement and Delinquency Outcomes Among System-Involved Youth Referred to Multisystemic Therapy: A Propensity Score Matching Analysis.

Multisystemic therapy (MST) was developed to help youth with serious social, emotional, and behavioral problems. Research on the efficacy and effectiveness of MST has shown positive outcomes in different domains of development and functioning among various populations of youth. Nonetheless, even with a large body of literature investigating the treatment effects of MST, few studies have focused on the effectiveness of MST through large-scale dissemination efforts. Utilizing a large sample of youth involved in a statewide dissemination of MST (n = 740; 43% females; 14% Black; 29% Hispanic; 49% White; Mage = 14.9 years), propensity score matching was employed to account for baseline differences between the treatment (n = 577) and comparison (n = 163) groups. Treatment effects were examined based on three outcomes: out-of-home placement, adjudication, and placement in a juvenile training school over a 6-year period. Significant group differences remained after adjusting for baseline differences, with youth who received MST experiencing better outcomes in offending rates than youth who did not have an opportunity to complete MST due to non-clinical or administrative reasons. Survival analyses revealed rates of all three outcomes were approximately 40% lower among the treatment group. Overall, this study adds to the body of literature supporting the long-term effectiveness of MST in reducing offending among high-risk youth. The findings underscore the potential benefits of taking evidence-based programs such as MST to scale to improve the well-being and functioning of high-risk youth. However, strategies to effectively deliver the program in mental health service settings, and to address the specific needs of high-risk youth are necessary.

The Interactive Effects of Stressful Family Life Events and Cortisol Reactivity on Adolescent Externalizing and Internalizing Behaviors.

This study investigated the associations between stressful family life events and adolescent externalizing and internalizing behaviors, and the interactive effects of family life events and cortisol reactivity on problem behaviors. In a sample of 100 mothers and their adolescents (M age = 15.09; SD age = .98; 68 % girls), adolescent cortisol reactivity was measured in response to a mother-adolescent conflict interaction task designed to elicit a stress response. Mothers reported on measures of family life events and adolescent problem behaviors. Results indicated that a heightened adolescent cortisol response moderated the relations between stressful family life events and both externalizing and internalizing behaviors. Results support context-dependent theoretical models, suggesting that for adolescents with higher cortisol reactivity (compared to those with lower cortisol reactivity), higher levels of stressful family life events were associated with greater problem behaviors, whereas lower levels of stressful family life events were related to fewer problem behaviors.

Associations Between Parental and Grandparental Marijuana Use and Child Substance Use Norms in a Prospective, Three-Generation Study.

PURPOSE: Using prospective longitudinal data from three generations, this study seeks to test whether and how parent and grandparent marijuana use (current and prior) predicts an increased likelihood of child cigarette, alcohol, and marijuana use. METHODS: Using multilevel modeling of prospective data spanning three generations (n = 306 families, children ages 6-22), this study tested associations between grandparent (G1) and parent (G2) marijuana use and child (G3) past-year cigarette, alcohol, and marijuana use. Analyses tested whether G3 substance-related norms mediated these associations. Current G1 and G2 marijuana use was examined, as was G2 high school and early adult use and G1 marijuana use when G2 parents were in early adolescence. Controls included G2 age at G3 birth, G2 education and depression, and G3 gender. RESULTS: G2 current marijuana use predicted a higher likelihood of G3 alcohol and marijuana use but was not related to the probability of G3 cigarette use. G3's perceptions of their parents' norms and G2 current marijuana use both contributed independently to the likelihood of G3 alcohol and marijuana use when included in the same model. G3 children's own norms and their perceptions of friends' norms mediated the link between G2 current marijuana use and G3 alcohol and marijuana use. CONCLUSIONS: Results are discussed in light of the growing trend toward marijuana legalization. To the extent that parent marijuana use increases under legalization, we can expect more youth to use alcohol and marijuana and to have norms that favor substance use.