Web-Based School Program Reduced Adolescent Drinking but Not Cannabis Use

A web-based prevention program delivered to over 6,000 Australian students increased alcohol and cannabis knowledge and reduced alcohol uptake, but did not significantly affect cannabis use.

Newton, Nicola C et al.·Psychological medicine·2022·Strong EvidenceRandomized Controlled Trial
RTHC-04098Randomized Controlled TrialStrong Evidence2022RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Randomized Controlled Trial
Evidence
Strong Evidence
Sample
N=3,236

What This Study Found

Students who received the Climate Schools program were 38% less likely to drink a full standard drink and 51% less likely to engage in heavy episodic drinking compared to controls at 12-month follow-up.

Key Numbers

Alcohol knowledge increased (standardized mean difference 0.51). Cannabis knowledge increased (SMD 0.49). Odds of drinking a full drink reduced by 38% (OR 0.62, p=0.014). Heavy episodic drinking reduced by 51% (OR 0.49, p=0.022). Cannabis use showed no significant difference (OR 0.57, p=0.22).

How They Did This

Cluster-randomized controlled trial across 71 secondary schools in three Australian states. Year 8 students (approximately age 13-14) received either the web-based Climate Schools: Alcohol and Cannabis course (n=3,236) or standard health education (n=3,150). Outcomes measured at baseline, 6, and 12 months.

Why This Research Matters

Few substance prevention programs for adolescents have demonstrated replicable effects. This large replication trial confirmed the program works for reducing alcohol use, which matters for schools choosing evidence-based curricula.

The Bigger Picture

This is one of the first large-scale replication trials for a web-based substance prevention program. The fact that it replicated alcohol effects but not cannabis effects raises questions about whether different strategies are needed for cannabis-specific prevention.

What This Study Doesn't Tell Us

The study relied on self-reported substance use. The program was developed for an Australian context and may not generalize to other countries. The 12-month follow-up is relatively short for assessing long-term prevention effects.

Questions This Raises

  • ?Why did the program reduce alcohol but not cannabis use despite increasing cannabis knowledge?
  • ?Would a cannabis-specific adaptation produce better outcomes?
  • ?Do prevention effects persist beyond 12 months?

Trust & Context

Key Stat:
51% reduction in heavy episodic drinking (OR 0.49)
Evidence Grade:
Strong: large cluster-RCT with over 6,000 students across 71 schools in three states, replicating prior findings.
Study Age:
Published in 2022.
Original Title:
A national effectiveness trial of an eHealth program to prevent alcohol and cannabis misuse: responding to the replication crisis.
Published In:
Psychological medicine, 52(2), 274-282 (2022)
Database ID:
RTHC-04098

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled TrialGold standard for testing treatments
This study
Cohort / Case-Control
Cross-Sectional / Observational
Case Report / Animal Study

Participants are randomly assigned to treatment or placebo groups to test cause and effect.

What do these levels mean? →

Frequently Asked Questions

Why did the program work for alcohol but not cannabis?

The researchers suggest the program may need cannabis-specific adaptations. Knowledge alone may not be sufficient to change cannabis behavior, or the 12-month window may have been too short to detect differences given lower baseline cannabis use rates.

Is the Climate Schools program available outside Australia?

The study tested it in Australia. International adaptations would need to account for cultural differences in drinking and drug use patterns.

Read More on RethinkTHC

Cite This Study

RTHC-04098·https://rethinkthc.com/research/RTHC-04098

APA

Newton, Nicola C; Chapman, Cath; Slade, Tim; Birrell, Louise; Healy, Annalise; Mather, Marius; McBride, Nyanda; Hides, Leanne; Allsop, Steve; Mewton, Louise; Andrews, Gavin; Teesson, Maree. (2022). A national effectiveness trial of an eHealth program to prevent alcohol and cannabis misuse: responding to the replication crisis.. Psychological medicine, 52(2), 274-282. https://doi.org/10.1017/S0033291720001919

MLA

Newton, Nicola C, et al. "A national effectiveness trial of an eHealth program to prevent alcohol and cannabis misuse: responding to the replication crisis.." Psychological medicine, 2022. https://doi.org/10.1017/S0033291720001919

RethinkTHC

RethinkTHC Research Database. "A national effectiveness trial of an eHealth program to prev..." RTHC-04098. Retrieved from https://rethinkthc.com/research/newton-2022-a-national-effectiveness-trial

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.