Combined prevention for substance use, depression, and anxiety in adolescence: a cluster-randomised controlled trial of a digital online intervention

BackgroundSubstance use, depression, and anxiety in adolescence are major public health problems requiring new scalable prevention strategies. We aimed to assess the effectiveness of a combined online universal (ie, delivered to all pupils) school-based preventive intervention targeting substance use, depression, and anxiety in adolescence.MethodsWe did a multicentre, cluster-randomised controlled trial in secondary schools in Australia, with...