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Study breakdown

Personality-Targeted Prevention Slowed Cannabis Use Escalation in At-Risk Teens Over 4 Years

Randomized Controlled TrialStrong evidence
The takeaway

A two-session, personality-targeted intervention for at-risk adolescents slowed the escalation of cannabis, alcohol, tobacco, and polysubstance use over four years in a JAMA Network Open trial of nearly 1,700 students.

School administrators, parents, and prevention professionals working with at-risk adolescents.

Two sessions reduced cannabis use escalation by 25% (OR=0.75) and polysubstance use by 44% (OR=0.56) over 4 years

What the researchers found

Students receiving PreVenture, a brief personality-targeted cognitive-behavioral intervention, showed slower increases in cannabis use (OR=0.75), tobacco smoking (OR=0.79), alcohol use (OR=0.92), and illicit polysubstance use (OR=0.56) over 4 years compared to controls. Effects did not differ by sex. The cannabis reduction was among the strongest effects observed.

Why it matters

Most substance prevention programs are universal and have modest effects. This study shows that targeting the specific personality traits that drive substance use in at-risk teens can produce meaningful reductions across multiple substances, including cannabis, with just two sessions.

The numbers in context

1,669 at-risk students (50.7% female, mean age 12.83). 31 schools randomized. Over 4 years: cannabis OR=0.75 (95% CrI: 0.66-0.86), tobacco OR=0.79 (0.70-0.96), alcohol OR=0.92 (0.85-1.00), polysubstance OR=0.56 (0.35-0.89). Effects similar for males and females.

How the study worked

Pre-specified secondary analysis of a cluster-randomized clinical trial. 1,669 at-risk grade 7 students from 31 Montreal-area secondary schools were randomized by school to receive PreVenture (15 schools, 705 students) or control (16 schools, 964 students). At-risk status was defined by elevated anxiety sensitivity, hopelessness, impulsivity, or sensation seeking. Published in JAMA Network Open.

What this study cannot tell us

Secondary analysis of a trial not primarily designed for cannabis outcomes. Montreal-area sample may not generalize to all populations. Cluster randomization by school introduces potential confounding. Self-reported substance use. Bayesian analysis framework differs from traditional frequentist approaches.

How to read the evidence

Strong: cluster-randomized clinical trial published in JAMA Network Open with large sample, 4-year follow-up, and pre-registered analysis.

When this study was published

2025 study (2012-2013 enrollment with 4-year follow-up).

The bigger picture

PreVenture has been tested in multiple countries and this secondary analysis extends its evidence base to cannabis specifically. The finding that a 2-session intervention can reduce cannabis use escalation by 25% over 4 years makes it one of the most efficient prevention tools available.

Questions still open

  • Would the intervention work as well in different cultural contexts? Could it be enhanced by adding cannabis-specific content? Does the effect persist beyond 4 years?

Common questions

How does the PreVenture program work?
It identifies teens with personality traits linked to substance use risk (anxiety sensitivity, hopelessness, impulsivity, sensation seeking) and delivers two targeted group sessions helping them recognize and manage personality-specific emotions and behaviors.
Does it only work for cannabis?
No. The intervention slowed escalation across cannabis, alcohol, tobacco, and polysubstance use. The cannabis effect (25% reduction) was actually one of the strongest effects observed.

Read the original research

Selective Personality-Targeted Intervention and the Escalation of Substance Use During Adolescence: A Secondary Analysis of A Cluster-Randomized Clinical Trial.

JAMA network open, 8(12), e2550176

Citation

Lynch, Samantha J; Stewart, Sherry H; Conrod, Patricia. (2025). Selective Personality-Targeted Intervention and the Escalation of Substance Use During Adolescence: A Secondary Analysis of A Cluster-Randomized Clinical Trial.. JAMA network open, 8(12), e2550176. https://doi.org/10.1001/jamanetworkopen.2025.50176

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