Longitudinal associations between adult-supervised drinking during adolescence and alcohol misuse from ages 25-31 years: A comparison of Australia and the United States.

Prior studies suggest that adult supervised drinking in adolescence predicts greater adolescent alcohol misuse. Long-term follow up data examining how adult supervised drinking during adolescence relates to alcohol misuse in adulthood are lacking. Longitudinal data from the International Youth Development Study tested associations between adult supervised drinking during adolescence (ages 13-16; 2002-2004) and adult alcohol misuse (ages 25-31; 2014, 2018, 2020). Cross-nationally matched samples were compared in Washington State, USA (n = 961) and Victoria, Australia (n = 1,957; total N = 2,918, 55 % female, 83 % White), where adult-supervised adolescent alcohol use was more common. Multilevel analyses adjusted for state, sex, adolescent drinking, parent education, family management, family history of substance use problems, and parent alcohol-related norms. Adult supervised drinking in adolescence (at dinner or parties, on holidays) predicted more adult alcohol misuse (mean Alcohol Use Disorders Identification Test score; b[SE] 0.07[0.03]; p = 0.004) and higher rates of alcohol-impaired driving (Odds Ratio [OR] 1.501, p = 0.034) and riding with an alcohol-impaired driver (OR 1.669, p = 0.005), but not the use of strategies to moderate alcohol intake (e.g., counting drinks). Better family management (monitoring, clear rules) in adolescence predicted less adult alcohol misuse. Associations were similar in the two states. Reducing the frequency of adult supervised drinking and improving family management practices in adolescence may help to decrease alcohol misuse well into adulthood. Findings support the widespread implementation of substance use prevention and family management training programs.

Youth Exposure to Recreational Cannabis Legalization: Moderation of Effects by Sex and Parental Cannabis Use during Adolescence.

OBJECTIVE: Few studies of recreational cannabis legalization (RCL) have assessed adolescents both before and after RCL or considered moderators of RCL effects. The present study tested whether RCL was more strongly associated with cannabis use for girls and among youth whose parents had a history of cannabis use during adolescence. METHOD: Data were pooled from 940 adolescents from three intergenerational studies that began in Washington (where RCL was enacted in 2012), Oregon (RCL year = 2015), and New York (RCL year = 2021). Youth were assessed repeatedly from ages 13 to 18 years (k = 3,650 person-years) from 1999 to 2020 (prior to RCL in New York). Parent cannabis use at or before age 18 years (yes/no) was assessed prospectively during the parent's adolescence. Multilevel models focused on the between-subjects effects of years of youth exposure to RCL on adolescents' mean cannabis use likelihood, and interactions with child sex and parent use history. RESULTS: Child exposure to RCL was associated with a higher likelihood of cannabis use if their parents had a history of adolescent use, (Estimate [SE] = 0.67 [0.25], p = 0.008), versus no such history (Estimate [SE] = -0.05 [0.28], p = 0.855). RCL effects were not moderated by child sex. CONCLUSIONS: The effects of RCL on adolescents' cannabis use may depend on their parents' history of using the drug. Identifying other moderators of RCL effects, and understanding the mechanisms of these risks and the ways that parents and communities can offset them, are prevention priorities.

(1) Adolescents' use of cannabis may have intergenerational consequences, making it more likely their future offspring will use cannabis. (2) Whether or not recreational cannabis legalization influences adolescents' cannabis use may depend on their parents' cannabis use history. (3) Parenting in a state with liberalized cannabis policies may present new challenges and require that novel prevention resources be developed.

Long-term Effects of the Raising Healthy Children Intervention on Family Functioning in Adulthood: A Nonrandomized Controlled Trial.

Some universal prevention programs, such as Raising Healthy Children (RHC), have shown persisting and wide-ranging benefits in adulthood, long after the intervention has ended. Recent studies suggest that benefits may continue into the next generation as well. This study examines whether the RHC intervention, delivered in childhood, may promote healthy family functioning among participants who now have families of their own. Participants were drawn from the Seattle Social Development Project (SSDP), a nonrandomized controlled trial of the RHC intervention prospectively following youths from 18 elementary schools in Seattle, Washington from 1985 to 2014. Participants who became parents were enrolled in an intergenerational study, along with their oldest biological child and an additional caregiver who shared responsibility for raising the child. Ten waves of data were collected between 2002 and 2018. The present analysis includes 298 SSDP parents, 258 caregivers who identified as a parent or partner of SSDP parent ("co-parent"), and 231 offspring. The SSDP parent sample was composed of 41.6% male, 21.1% Asian or Pacific Islander, 24.2% Black or African American, 6.4% Native American, and 48.3% white individuals. No significant intervention effects were found on adult romantic relationship quality; offspring bonding to co-parent; or co-parent past-month use of cannabis, cigarettes, or binge drinking. Findings highlight the continued need to understand how the benefits of theory-guided universal preventive interventions are sustained across the life course and how they may or may not shape family functioning for those who go on to have families and children of their own.ClinicalTrials.gov Identifier: NCT04075019.

Health and Social Vulnerabilities Among Unstably Housed and Homeless Young Adults During the COVID-19 Pandemic.

The role of housing as a social driver of health is well-established, with stable housing being an important factor in reducing health inequities. During developmentally critical periods such as young adulthood, unstable housing and related social marginalization have profound effects on development and later health, social, and economic wellbeing. This exploratory study analyzed data from a population-based, longitudinal sample of young adults (average age 31 years) from Washington State (n = 755) to compare health and economic impacts of the early days of the COVID-19 pandemic, with a focus on housing status. Descriptive results suggest the pandemic exposed underlying vulnerabilities for young adults experiencing homelessness and housing instability, with an overall widening of inequities related to financial difficulties and increased risk for poor mental health and social isolation. Findings suggest that these vulnerabilities are magnified in the context of public health crises and strengthen the case for population-based studies investigating potential modifiable causes of housing instability to inform prevention and early intervention at the earliest possible point in a young person's development. Studies examining the severity of COVID-related hardships on young adult health and social outcomes are vital for establishing an evidence base for strategic policy action that seeks to prevent a rebound in young adult homelessness and housing instability post-pandemic. These studies would bolster both emergency preparedness responses that account for the unique needs of vulnerable populations and upstream population-level prevention approaches beginning long before the imminent risk for housing instability develops.

Alcohol-Tolerant Workplace Environments Are a Risk Factor for Young Adult Alcohol Misuse on and off the Job in Australia and the United States.

The workplace has been understudied as a setting for the prevention of young adult alcohol misuse. This study examined if alcohol-tolerant workplace environments are associated with greater risk for alcohol use and misuse on and off the job among young adults. Data were collected in 2014 from state-representative, sex-balanced samples (51% female) of 25-year-olds in Washington, U.S. (n = 751) and Victoria, Australia (n = 777). Logistic regressions indicated that availability of alcohol at work, absence of a written alcohol policy, and alcohol-tolerant workplace norms and attitudes were independently associated with a 1.5 to 3 times greater odds of on-the-job alcohol use or impairment. Alcohol-tolerant workplace norms were associated also with greater odds of high-risk drinking generally, independent of on-the-job alcohol use or impairment. Associations were mostly similar in Washington and Victoria, although young adults in Victoria perceived their workplaces to be more alcohol-tolerant and were more likely to use alcohol or be impaired at work and to misuse alcohol generally than young adults in Washington. Cross-nationally, workplace interventions that restrict the availability of alcohol, ban alcohol at work, and reduce alcohol-tolerant norms have the potential to prevent and reduce young adults' alcohol use and misuse on and off the job.

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.

Adolescent Predictors of Deliberate Self-Harm Thoughts and Behavior Among Young Adults: A Longitudinal Cross-National Study.

PURPOSE: This study builds upon and extends previous longitudinal research on deliberate self-harm (DSH) among youth by investigating which risk and protective factors during adolescence predict DSH thoughts and behavior in young adulthood. METHODS: Self-report data came from 1,945 participants recruited as state-representative cohorts from Washington State and Victoria, Australia. Participants completed surveys in seventh grade (average age 13 years), as they transitioned through eighth and ninth grades and online at age 25 years. Retention of the original sample at age 25 years was 88%. A range of risk and protective factors in adolescence for DSH thoughts and behavior in young adulthood were examined using multivariable analyses. RESULTS: Across the sample, 9.55% (n = 162) and 2.83% (n = 48) of young adult participants reported DSH thoughts and behaviors, respectively. In the combined risk-protective factor multivariable model for young adulthood DSH thoughts, depressive symptoms in adolescence (adjusted odds ratio [AOR] = 1.05; confidence interval [CI] = 1.00-1.09) increased risk, while higher levels of adolescent adaptive coping strategies (AOR = 0.46; CI = 0.28-0.74), higher levels of adolescent community rewards for prosocial behavior (AOR = 0.73; CI = 0.57-0.93), and living in Washington State decreased risk. In the final multivariable model for DSH behavior in young adulthood, less positive family management strategies during adolescence remained the only significant predictor (AOR = 1.90; CI = 1.01-3.60). DISCUSSION: DSH prevention and intervention programs should not only focus on managing depression and building/enhancing family connections and support but also promote resilience through efforts to promote adaptive coping and connections to adults within one's community who recognize and reward prosocial behavior.

Health of Young Adults Experiencing Social Marginalization and Vulnerability: A Cross-National Longitudinal Study.

People who experience social marginalization and vulnerability have uniquely complex health needs and are at risk of poor health outcomes. Regression analyses using longitudinal data from a cross-national, population-based sample of young adults participating in the International Youth Development Study, tested associations between social marginalization and vulnerabilities and physical health, mental health, and substance use outcomes. Participants from Victoria, Australia, and Washington State in the US were surveyed at ages 25 (2014) and 29 years (2018; N = 1944; 46.7% male). A history of adverse childhood experiences (ACEs), LGBT identity, financial insecurity, and justice system involvement at age 25 predicted poor health outcomes at age 28, including lower perceived health status, risk for chronic illness, depression and anxiety symptoms, and diagnosed mental health/substance use disorders. Tests of model equivalence across states showed that a history of ACEs was more strongly related to health status and serious injury at age 28 and justice system involvement at age 25 was more strongly related to age 28 serious injury in Victoria than in Washington State. Findings strengthen the case for future population-based research identifying life-course interventions and state policies for reducing poor health and improving health equity among members of socially marginalized groups.

Effects of Cannabis Legalization on Adolescent Cannabis Use Across 3 Studies.

INTRODUCTION: Canada, Uruguay, and 18 states in the U.S. have legalized the use of nonmedical (recreational) cannabis for adults, yet the impact of legalization on adolescent cannabis use remains unclear. This study examined whether cannabis legalization for adults predicted changes in the probability of cannabis use among adolescents aged 13-18 years. METHODS: Data were drawn from 3 longitudinal studies of youth (spanning 1999-2020) centered in 3 U.S. states: Oregon, New York, and Washington. During this time, Oregon (2015) and Washington (2012) passed cannabis legalization; New York did not. In each study, youth average age was 15 years (total N=940; 49%-56% female, 11%-81% Black/African American and/or Latinx). Multilevel modeling (in 2021) of repeated measures tested whether legalization predicted within- or between-person change in past-year cannabis use or use frequency over time. RESULTS: Change in legalization status across adolescence was not significantly related to within-person change in the probability or frequency of self-reported past-year cannabis use. At the between-person level, youth who spent more of their adolescence under legalization were no more or less likely to have used cannabis at age 15 years than adolescents who spent little or no time under legalization. CONCLUSIONS: This study addresses several limitations of repeated cross-sectional studies of the impact of cannabis legalization on adolescent cannabis use. Findings are not consistent with changes in the prevalence or frequency of adolescent cannabis use after legalization. Ongoing surveillance and analyses of subpopulations are recommended.

School Influences on Adolescent Depression: A 6-Year Longitudinal Study Amongst Catholic, Government and Independent Schools, in Victoria, Australia.

This study examined associations between school sector (Government, Catholic or Independent) and depressive symptomology over the secondary school years. Six waves of data collected annually from a representative Australian sample were examined. Multilevel piecewise linear and logistic regression controlling for a variety of demographic variables and protective factors was undertaken. In all sectors, depressive symptomology decreased between 10 and 13 years of age, but significantly increased for girls at age 13. Adolescents in Catholic schools reported significantly fewer symptoms of depression compared to those in Government and Independent schools. Adolescents in Catholic schools were less likely to report clinical levels of depressed mood compared to adolescents in Government schools.

A population-based study of homelessness, antisocial behaviour and violence victimisation among young adults in Victoria, Australia.

Homeless young adults are at increased risk for contact with the police and are overrepresented in the justice system. This study explored associations between homelessness, antisocial behaviour and violence victimisation using longitudinal panel data gathered through young adulthood. Data were drawn from a state representative population-based sample of young adults from Victoria, Australia participating in the International Youth Development Study (IYDS; n = 2884, 54% female). Participants were surveyed at age 21 years, with follow-up at ages 23 and 25 years. We examined changes in the prevalence of homelessness and tested hypothesised directional relationships between young adult homelessness, antisocial behaviour and violence victimisation using longitudinal cross-lagged panel models. Multiple-group modelling was used to test whether these relationships were moderated by gender. The prevalence of young adult homelessness was highest at age 21 (6.5%), declining at ages 23 (3.9%) and 25 years (2.5%). Results showed that young adult homelessness, antisocial behaviour and victimisation were related cross-sectionally, but not longitudinally. Gender did not significantly moderate these associations. Findings suggest that the state of homelessness is associated with temporary vulnerability to potentially harmful and problematic situations involving antisocial behaviour and victimisation. These situations are likely to heighten risk for contact with the police and direct physical and psychological harm.

Young Adult Development Indicators for Indigenous and Non-Indigenous People: A Cross-National Longitudinal Study.

Worldwide, Indigenous youth face ongoing challenges and inequalities. Increasing our understanding of life course patterns in Indigenous youth will assist the design of strategies and interventions that encourage positive development. This study aimed to increase understanding of resilience and positive development in Indigenous and non-Indigenous youth across Australia and the United States of America. The Australian sample comprised 9680 non-Indigenous and 176 Pacific Islander and Aboriginal and Torres Strait Islander peoples. The USA sample comprised 2258 non-Indigenous and 220 Pacific Islander, Native Hawaiian and Native American/American Indian peoples. Data were used to examine how Indigenous background, volunteering, and community involvement at average age 15 years (Grade 9) predicted five young adult positive development indicators: Year 12 (Grade 12) school completion, tertiary education participation, independent income, paid employment, and intimate relationship formation from age 18 to 28 years. Multilevel regression analyses revealed that while Indigenous youth showed slower increases in positive young adult development over time, when adjusting for socioeconomic disadvantage, there was a reduction in this difference. Moreover, we found that Grade 9 community involvement and volunteering were positively associated with young adult development for Indigenous and non-Indigenous youth. Findings indicate the importance of addressing structural inequalities and increasing adolescent opportunities as feasible strategies to improve positive outcomes for young Indigenous adults.

Young adult opioid misuse indicates a general tendency toward substance use and is strongly predicted by general substance use risk.

OBJECTIVE: To examine whether young adult opioid misuse reflects a general tendency toward substance use and is influenced by general substance use risk or whether it is a different phenomenon from other drug use. METHODS: At ages 23 (2016) and 26 (2019), a panel of young adults (n = 3794 to 3833) in the United States self-reported their past-month substance use (opioid misuse, heavy drinking, cigarettes, cannabis) and substance-specific risk factors (perceptions of harm; approval of use; and use of each substance by friends and romantic partners). Structural equation models examined non-opioid and opioid-specific associations between latent risk and substance use factors. RESULTS: Opioid misuse and opioid-specific risk factors shared significant variance with latent substance use and latent substance use risk, respectively, which were strongly associated. A statistically significant residual correlation between opioid-specific risk and opioid misuse remained. CONCLUSION: Young adult opioid misuse reflects a general tendency toward substance use and is strongly predicted by risk for substance use. Opioid-specific risk factors play only a small independent role. Existing evidence-based substance use interventions may be effective in preventing opioid misuse among young adults.

Is e-cigarette use associated with better health and functioning among smokers approaching midlife?

INTRODUCTION: Many adult smokers have tried electronic cigarettes (e-cigarettes) as a less harmful alternative to combustible cigarettes. There is limited evidence, however, for the extent to which switching to e-cigarettes is associated with better health and functioning among nicotine users approaching their 40s-the beginning of midlife-when many health issues become more evident. This study examined the adoption of e-cigarette use ("vaping") among smokers in their 30s, and its association with diverse measures of healthy and successful aging at age 39. METHODS: Data were from the Seattle Social Development Project, a panel study of 808 diverse participants with high retention (88%-91%). A subsample of 156 who used combustible cigarettes (smoked) at age 30 and smoked or vaped at age 39 was selected for analysis. A measure of vaping frequency, relative to combustible cigarette use, was computed from self-reports of past-month vaping and smoking at age 39. Nine measures of health and functioning in the past year were computed at age 39, with nine corresponding measures at age 30. RESULTS: Among smokers at age 30, 36% adopted vaping some or all of the time by age 39. Higher relative vaping frequency was related to 4 of 9 outcomes examined, including significantly more exercise, more constructive engagement, better physical health, and higher SES at age 39, accounting for prior behaviors at age 30. CONCLUSIONS: Findings suggest that, among smokers in their 30s, replacing combustible cigarettes with vaping may be associated with key markers of healthy and successful aging to age 39.

Parent ENDS use predicts adolescent and young adult offspring ENDS use above and beyond parent cigarette use.

PURPOSE: Prior research has showed that parent combustible cigarette use predicts cigarette use among their offspring. This study used prospective longitudinal data from parents and offspring to test whether parent electronic nicotine delivery system (ENDS) use predicted a higher probability of ENDS use among their offspring. METHODS: Data were drawn from the Seattle Social Development Project - The Intergenerational Project (SSDP-TIP). Analyses included 295 families; 7% of parents were Native American/Alaskan Native, 18% were Asian American, 28% were African American, and 47% were European American. Multilevel modeling (in 2020) of data collected in 2015, 2016, and 2017 tested associations between parent self-reported ENDS use and concurrent self-reported ENDS use among offspring ages 10-25 years (53% female). Parent combustible cigarette use was controlled. Analyses also examined the role of parent and offspring perceptions of the safety of ENDS in predicting offspring ENDS use. RESULTS: About 12% of offspring and 8% of parents reported past-month ENDS use. Parent ENDS use predicted a higher probability of child ENDS use (Odds Ratio 5.68, p = .01), even after controlling parent past month cigarette use. Beyond parent nicotine product use, offspring perceptions of ENDS safety - but not parent perceptions of ENDS safety - contributed independently to offspring probability of past-month ENDS use. CONCLUSIONS: It is important for parents, health providers, and policymakers to focus on preventing ENDS use among offspring of parents who use ENDS.

Adolescent Antecedents of Young Adult Homelessness: a Cross-national Path Analysis.

Adolescent and young adult health, development, and behavior lay a foundation for future population health. Increasing rates of young adult homelessness mean there is a need for research which generates evidence to support a stronger focus on population-level prevention. Using longitudinal data from a population-based sample of young adults participating in the cross-nationally matched International Youth Development Study, we examined adolescent antecedents of young adult homelessness in Washington State in the USA and in Victoria, Australia. Participants were surveyed using a modified version of the Communities That Care youth survey. Analyses of prospective, longitudinal data from 1945 participants, recruited as state-representative secondary school samples at grade 7 (average age 13, 2002) and longitudinally compared at young adulthood (average age 25, 2014), showed that young adults in Washington State reported higher rates of past year homelessness (5.24%) compared to those in Victoria (3.25%). Path modeling showed less positive family management strategies at age 13 uniquely increased risk for age 25 homelessness. This effect remained after accounting for age 15 antecedents in peer-group, school, and community environments. Friends' drug use, school suspension, academic failure, and low neighborhood attachment at age 15 mediated the association between less positive family management strategies at age 13 and age 25 homelessness. Despite observing some cross-national differences in levels of family, peer-group, school, and community antecedents, we found that these factors equally increased risk for age 25 homelessness in both states, suggesting similar cross-national influences for young adult homelessness. The findings indicate cross-nationally common adolescent antecedents for young adult homelessness that could be targeted by prevention strategies across international settings.

Does Parents' Age at First Birth Moderate Intergenerational Continuity in Early-Onset Cannabis Use?

OBJECTIVE: The aims of this brief report were to examine the extent to which early onset of cannabis use by parents and their children, and intergenerational continuity in early-onset cannabis use by parents and children, differ as a function of parent age at birth of first child. METHOD: A total of 795 parent-child dyads (57% male parents and 49% male children) were compiled from three intergenerational studies: Oregon Youth Study-Three Generational Study (OYS-3GS), Rochester Youth Development Study and Rochester Intergenerational Study (RYDS-RIGS), and Seattle Social Development Project-The Intergenerational Project (SSDP-TIP). Parents and children identified as non-Hispanic White (29% and 22%, respectively), Black (55% and 47%), and Hispanic (8% and 11%). Early-onset cannabis use was defined as initiation at or before age 15. Time-varying effect models were fit to examine the research questions. RESULTS: Among parents, earlier initiation of cannabis use was associated with an earlier entry into parenthood. Moreover, parents' later age at first birth was predictive of a lower prevalence of early-onset cannabis use among their children. Last, regarding intergenerational continuity, parental early onset of cannabis use increased the likelihood of child early-onset use, but only among older parents (i.e., later age at first birth). CONCLUSIONS: We provide a nuanced examination of the associations between parental and child early-onset cannabis use as a function of parents' age at first birth and describe a novel approach to incorporating parent's age at first birth into models of intergenerational continuity.

The role of electronic cigarette use for quitting or reducing combustible cigarette use in the 30s: Longitudinal changes and moderated relationships.

BACKGROUND: Evidence for use of electronic cigarettes (e-cigs) as a potential aid in quitting or reducing combustible cigarette (c-cig) use is mixed. This study examined the extent to which e-cig initiation among smokers in their 30 s predicted quitting or reducing smoking or nicotine dependence symptoms by age 39, and whether the role of e-cigs in quitting differed by prospectively assessed moderators. METHODS: Data were from the Seattle Social Development Project (SSDP), a panel study of 808 diverse participants with high retention. A subsample of 221 smokers at age 33 was selected for analysis. Self-reports of c-cig use and dependence were assessed longitudinally at ages 33 and 39. Sixteen potential moderators were examined, including social demographics, smoking attitudes and desire to quit, other health behaviors and status, and adolescent and early adult assessments of smoking history. RESULTS: The use of e-cigs was consistently associated with a lower likelihood of quitting c-cigs by age 39, after accounting for frequency of prior c-cig use at age 33. This negative association persisted across all moderators examined, although it was nonsignificant among those with a definite desire to cut down. Among those who did not quit smoking, e-cig use had no association with decreases in either quantity of c-cigs used or dependence symptoms. CONCLUSIONS: Results indicate that e-cigarette use was not helpful for quitting or reducing combustible cigarette use in the 30 s. Rather, across extensive tests of moderation, e-cig initiation consistently predicted less quitting during this important age period for successful cessation.

Life-course predictors of homelessness from adolescence into adulthood: A population-based cohort study.

INTRODUCTION: Internationally, the prevalence of young adult homelessness is concerning. Few data on life-course predictors from longitudinal studies exist, limiting our capacity to inform prevention strategies at the population-level. METHODS: Data were drawn from a state representative population-based sample of young adults from Victoria, Australia participating in the International Youth Development Study (IYDS; N = 927, 54% female). Participants were recruited in state-representative secondary school samples at Grade 7 (age 13, 2002), with follow-up in Grades 9 (age 15) and 11 (age 17) and at ages 21, 23 and 25. Using longitudinal path modelling, we conducted a series of analyses testing life-course predictors of young adult homelessness across multiple socializing contexts, and the interrelationships among them. RESULTS: The rate of young adult homelessness was 5.5%. Path modelling showed higher levels of family conflict at ages 13 and 15 uniquely predicted homelessness by age 25. This effect remained after accounting for other risk factors in peer-group (e.g., interactions with antisocial peers), school (e.g., low academic performance), and community contexts (e.g., low neighborhood attachment). Peer drug use and interaction with antisocial peers at age 15 mediated the association between family conflict at age 13 and homelessness by age 25. CONCLUSIONS: Findings point to the vulnerability of early adolescents to family conflict. This vulnerability heightens risk for young adult homelessness. Findings strengthen the case for both primary prevention programs that build healthy relationships between family members from early on in adolescence and for investment in homelessness prevention at key developmental periods.