Childhood cigarette and alcohol use were the strongest predictors of early cannabis use, with family factors also contributing | Research

The takeaway

In 852 Australian adolescents followed through age 19, early substance use (cigarettes and alcohol) and family factors in fifth grade were the strongest predictors of cannabis use patterns through adolescence.

Substance use prevention researchers, school-based intervention developers, and pediatricians.

Early substance use in childhood: RRR 2.64 for early cannabis onset

What the researchers found

Among 852 adolescents, 10.7% showed early-onset cannabis use (before age 15). The strongest predictors were childhood cigarette use and drinking until drunk. Family factors (poor management, antisocial family history, parent attachment) predicted early onset specifically. Cumulative risk from early substance use was the strongest independent predictor of both early-onset cannabis use (RRR 2.64, CI 1.40-4.97) and late-onset occasional use (27%). Family-related cumulative risk also predicted late-onset use.

Why it matters

Prevention is most effective when targeted at the right age. This study identifies fifth-grade risk factors that predict cannabis trajectories years later, offering a specific prevention window and specific targets (early substance use, family environment).

The numbers in context

852 adolescents; 10.7% early onset; 27% late occasional onset; cigarette use and drinking strongest predictors; cumulative early substance use risk RRR 2.64; poor family management, family antisocial history, parent attachment also predicted early onset.

How the study worked

Prospective longitudinal study of 852 adolescents (53% female) from the Australian International Youth Development Study, with risk/protective factors measured in fifth grade (mean age 10.9) and cannabis use measured at 6 time points from ages 12-19.

What this study cannot tell us

Australian sample (may not generalize to other contexts); self-report at all time points; 53% female (slightly unbalanced); risk factors measured at single time point in fifth grade; does not assess cannabis potency or type.

How to read the evidence

Strong: prospective longitudinal design from age 10.9 through 19 with validated measures at multiple time points.

When this study was published

Published 2020.

The bigger picture

The finding that early alcohol and cigarette use outpredict family and peer factors for cannabis onset reinforces the gateway sequence: legal substance use in childhood is the strongest entry point. Delaying first alcohol and cigarette use may be the most effective cannabis prevention strategy.

Questions still open

Would delaying alcohol/cigarette initiation by even 1-2 years reduce cannabis onset? Do family-based interventions in late childhood prevent early cannabis use?

Common questions

What predicts early cannabis use?

The strongest predictor was early cigarette and alcohol use in childhood. Family factors (poor management, antisocial history, weak parent attachment) in fifth grade also predicted early-onset cannabis use, which occurred in 10.7% of the sample.

Can cannabis use be prevented?

This study suggests the most effective prevention targets are delaying first cigarette and alcohol use and improving family environments during late childhood (around age 10-11), years before cannabis use typically begins.

Read the original research

Childhood social environmental and behavioural predictors of early adolescent onset cannabis use.

Drug and alcohol review, 39(4), 384-393

View on PubMed ↗Publisher’s paper ↗

Citation

Scholes-Balog, Kirsty E; Hemphill, Sheryl A; Heerde, Jessica A; Toumbourou, John W; Patton, George C. (2020). Childhood social environmental and behavioural predictors of early adolescent onset cannabis use.. Drug and alcohol review, 39(4), 384-393. https://doi.org/10.1111/dar.13077