Study protocol for a cluster randomised controlled trial of The Illicit Project, a digital, neuroscience-based substance use intervention for secondary school students

An on-line school-based substance use harm reduction programme: The Illicit Project randomized controlled trial results

AIMS

The aim of this study was to measure the effectiveness of an on-line, neuroscience-based harm reduction intervention (The Illicit Project) on substance use, harms and knowledge over a 12-month period.

DESIGN

We used a two-arm cluster-randomized controlled trial.

SETTING

The study was conducted at eight secondary schools across New South Wales, Australia.

PARTICIPANTS

A total of 950 (mean age = 15.9; standard deviation = 0.68) in grades 10-12 at participating schools in 2020 took part.

INTERVENTION AND COMPARATOR

The Illicit Project intervention group (schools = five, n = 681) received an on-line, universal substance use and harm reduction programme over three classes. The active control group (schools = three, n = 269) received school-based health education as usual.

MEASUREMENTS

Self-report questionnaires assessed primary [alcohol, nicotine, cannabis, 3,4-methylenedioxymethamphetamine (MDMA), cocaine and prescription drug misuse] and secondary outcomes (alcohol-related harms and drug literacy) at baseline and the 6- and 12-month follow-up assessment.

FINDINGS

Approximately 63% (n = 595) of the sample completed the 12-month follow-up assessment, including 58% of the intervention group (n = 396/679) and 66% of the active control group (n = 179/271). Participants in the intervention group had slower annual increases in binge drinking [odds ratio (OR) = 0.33, 95% confidence interval (CI) = 0.12-0.89], nicotine use (OR = 0.80, 95% CI = 0.52-1.23), MDMA use (OR = 0.14, 95% CI = 0.02-1.00), cocaine use (OR = 0.06, 95% CI = 0.01-0.64) and prescription drug misuse (OR = 0.07, 95% CI = 0.01-0.54) compared with the active control group. There was limited evidence of an intervention effect on cannabis use and alcohol-related harm (P > 0.5). The secondary outcomes showed that the intervention group maintained higher levels of drug literacy knowledge (β = 3.71, 95% CI = 1.86-5.56) and harm reduction help-seeking skills (β = 1.55, 95% CI = 0.62-2.48) compared with the active control group.

CONCLUSION

The Illicit Project (an on-line, neuroscience-based substance use harm reduction intervention) was effective in slowing the uptake of risky substance use and improving drug literacy skills among late secondary school students in Australia, compared with school-based health education as usual.

Effectiveness of a neuroscience-based, harm reduction program for older adolescents: A cluster randomised controlled trial of the Illicit Project

The prevention of risky adolescent substance use is critical. Limited age-appropriate, school-based programs target adolescents aged 16-19 years, despite this representing the age of initiation and escalation of substance use. The Illicit Project is a neuroscience-based, harm reduction program targeting late adolescents, designed to address this gap. The current study aims to evaluate the program's effectiveness in reducing risky substance use and related harms among late adolescents. A cluster randomised controlled trial was conducted involving 950 students (Mage = 15.9 years SD = 0.68; 60% Female) from eight secondary schools in Australia. Five schools received The Illicit Project program, and three schools were randomised into the active control group (health education as usual). All students completed a self-report survey at baseline and 6-months post-baseline and intervention students completed a program evaluation survey. Outcomes include alcohol and substance use, alcohol related harms and drug literacy levels (knowledge and skills). At 6-months post baseline, individuals in the intervention group were less likely to engage in weekly binge drinking (OR = 0.56), high monthly alcohol consumption (OR = 0.56), early onset cannabis use (OR = 0.35), risky single occasion cannabis use (OR = 0.48), MDMA use (OR = 0.16) or nicotine product use (OR = 0.59) compared to the control group. Students in the intervention group were less likely to have experience alcohol related harms (OR = 0.57) and more likely to have higher drug literacy scores (β = 2.44) at follow-up. These preliminary results support the effectiveness of The Illicit Project. Further follow-up is required to determine the durability of the results over time.