Developing a mobile-based brief intervention to reduce cannabis-impaired driving among youth: An intervention mapping approach.

Behaviour change interventions delivered via smartphones have the potential to reduce youth cannabis use and driving under the influence of cannabis (DUIC). Countless smartphone applications (either downloadable or web-based) are available to help reduce substance use and impaired driving. However, most are developed without evidence-based content and theory, and many have poor user engagement. This study aims to: (1) describe the systematic development and theoretical foundations of a youth DUIC smartphone intervention, and (2) describe the pre-testing among a sample of youth and adult cannabis educators (prior to efficacy testing). A 6-step Intervention Mapping approach was utilized to combine theory, evidence, and user feedback to develop and implement the 'High Alert' intervention. This evidence-based and iterative process entailed: (1) conducting a needs assessment, (2) identifying intervention objectives, which map on the following DUIC determinants: knowledge, attitudes, risk perception, perceived norms, and self-efficacy, (3) selecting intervention theory and design, (4) developing of the intervention, (5) implementation, and (6) evaluation. Application of Intervention Mapping resulted in a smartphone web-based application that could support reductions in cannabis use and DUIC. The 'High Alert' intervention was created to include four modules with contents focusing on educating youth on the dangers and legal risks of DUIC, limiting risky situations, avoiding riding with an impaired driver, planning a safe ride home, and promoting safer cannabis use. Future research will test the efficacy of the intervention in reducing risky cannabis use and DUIC among youth.