Durability of anxiety, depression, and substance use prevention effects from teenage years to young adulthood: 6-year outcomes from a school-based cluster randomised controlled trial delivered in adolescence.
Substance use, depression, and anxiety frequently co-occur and are the leading causes of disability among young people globally. New scalable prevention strategies are needed to address this major public health concern. While early prevention in teenage years is critical, the durability of prevention effects into young adulthood is unclear. This presentation will examine the sustainability of combined mental health and substance use school-based prevention across the transition from adolescence to adulthood.
A multicentre, cluster-randomised controlled trial was conducted in 2014 with 6386 students (mean age: 13.5 years) from 71 secondary schools in Australia. Schools were randomly assigned to one of four intervention conditions: (1) Climate Schools–Substance Use, focusing on substance use only; (2) Climate Schools–Mental Health, focusing on depression and anxiety only; (3) Climate Schools–Combined, focusing on the prevention of substance use, depression, and anxiety; or (4) active control. The CSC long-term follow-up study extends the follow-up period to 6 years post baseline, with assessments conducted between 2018 and 2021. Primary outcomes were self-reported alcohol use, depression, and anxiety. Multilevel mixed-effects regression and generalized mixed-effects models will be used to assess these outcomes.
A total of 1877 participants (mean age 20 years; 63% female) completed a long-term assessment occasion. Six years after inclusion in a multi-site RCT, adolescents who had received the CSC prevention program reported reduced odds of drinking alcohol (OR 0.22; CI 0.08, 0.61) and reduced odds of binge drinking (OR 0.12; CI 0.05, 0.33) however, we found no significant difference in cannabis use, anxiety or depression scores, compared to adolescents who received health education as usual (the control condition).
Long-term assessment of school-based prevention programs is vital to determine the durability of substance use and mental health prevention across the critical transition period transition from adolescence to early adulthood.