Cost-Utility Analysis of a School-Based Universal Program for the Prevention of Anxiety, Depression, and Substance Use: The Climate Schools Combined Trial

This cost-utility analysis adopted societal and health sector perspectives evaluating combined and individual approaches to universal prevention of substance use, depression, and anxiety in 6,386 high school students within the Climate Schools Combined cluster randomised trial. Costs included program delivery, self-reported healthcare utilisation, and lost productivity. Quality-adjusted life years (QALYs) over 60 months were calculated with Child Health Utility 9D utility values. Incremental cost-effectiveness ratios (ICERs) were calculated as mean difference in costs divided by mean difference in QALYs. Intention-to-treat analyses found the combined approach led to non-significant lower societal costs and improved QALYs over individual prevention or usual education. Compared to individual mental health prevention, the combined approach had non-significant higher health sector costs and improved QALYs, with an ICER below the Australian willingness-to-pay threshold of $50,000/QALY. These results suggest that combined online universal prevention for mental health and substance use disorders likely represents value for money. This trial is registered with the Australian and New Zealand Clinical Trials registry on 01 July 2013. TRN: ACTRN12613000723785.