Early adolescents followed distinct trajectories of increasingly positive cannabis expectations, with family monitoring and peer substance use emerging as key factors shaping whether beliefs stayed low or escalated.
Parents of preteens, school-based prevention program designers, developmental psychologists studying substance use risk.
What the researchers found
Using three waves of longitudinal data from the ABCD Study, researchers identified distinct developmental trajectories in how early adolescents (ages 10–13) formed positive expectations about cannabis — beliefs about anticipated benefits of use that are known predictors of actual cannabis initiation.
Latent class growth analysis revealed that not all adolescents follow the same path. Some maintained consistently low positive expectations over time, while others showed escalating trajectories where beliefs about cannabis benefits increased as they moved through early adolescence.
The key predictors of trajectory membership were familial factors that changed over time. Parental monitoring — how well parents tracked their children's activities and whereabouts — was associated with lower positive expectancy trajectories. Conversely, family conflict and peer substance use were associated with escalating expectancies.
Baseline sociodemographic factors and state-level policy variables were also examined as predictors of which trajectory a child would follow, providing a multi-level picture of what shapes cannabis attitudes before use begins.
Why it matters
Positive expectations about cannabis are one of the strongest cognitive predictors of whether an adolescent will start using. Understanding how these beliefs develop — and what family and social factors shape their trajectory — provides actionable targets for prevention before cannabis use begins.
The numbers in context
Three waves of longitudinal data, ages 10–13. Multiple trajectory classes identified via latent class growth analysis. Key time-varying predictors: parental monitoring (protective), family conflict (risk), peer substance use (risk). Baseline predictors: sociodemographic and state-level policy factors.
How the study worked
Longitudinal study using latent class growth analysis with three waves of ABCD Study data (ages 10–13). Identified distinct developmental trajectories of positive cannabis use expectancies. Multinomial logistic regression tested baseline predictors of class membership. Time-varying familial factors (parental monitoring, family conflict, peer substance use) examined as trajectory modifiers.
Who was studied
N=7,409 adolescents aged 10-13, 50% male, diverse US cohort from the ABCD Study.
What this study cannot tell us
ABCD Study participants may not represent all early adolescents. Positive expectancies are a proxy for future use, not actual use outcomes. Three measurement waves may not capture all trajectory variation. Self-reported parental monitoring and family conflict may not reflect actual dynamics. Unmeasured confounders (e.g., mental health, trauma) could influence both family factors and expectancies.
How to read the evidence
Longitudinal cohort analysis with sophisticated growth modeling — strong for identifying developmental patterns but cannot confirm causal effects of family factors on expectancies.
When this study was published
Published in 2026 using recent ABCD Study data, tracking expectancy development in a contemporary cohort of early adolescents.
The bigger picture
This connects to the discrimination-to-intention pathway study (RTHC-00264) by examining a different set of precursors to cannabis use. Where that study focused on racial discrimination as a driver, this one focuses on family dynamics and peer influence. Together with the college student policy study (RTHC-00253), they build a developmental picture: early expectations form in the family context, are shaped by peer and social factors including discrimination, and then interact with state-level policies during the college years.
Replication
Not stated in abstract.
Funding
Not reported in abstract.
Conflicts of interest
Not reported in abstract.
Questions still open
- Do the escalating expectancy trajectories actually predict cannabis initiation in later ABCD data? Can parenting interventions that increase monitoring effectively shift adolescents from escalating to stable-low trajectories? At what age do peer influences begin to outweigh family influences on cannabis attitudes?
Read the original research
Developmental Trajectories of Positive Expectancies of Cannabis Use Effects Among Early Adolescents: Longitudinal Observational Study Using Latent Class Growth Analysis.
JMIR public health and surveillance, 12, e85652
JMIR Public Health and Surveillance is a reputable journal focusing on public health research and surveillance.
Citation
Qin, Weisiyu Abraham; Seo, Dong-Chul; Jacobs, Wura; Huang, Sijia; Elam, Kit K. (2026). Developmental Trajectories of Positive Expectancies of Cannabis Use Effects Among Early Adolescents: Longitudinal Observational Study Using Latent Class Growth Analysis.. JMIR public health and surveillance, 12, e85652. https://doi.org/10.2196/85652
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