Substance use disorder treatment is a complex problem. Complex problems require complex interventions, ideally tested via randomised controlled trials. Complex interventions are best developed in stages, using established implementation frameworks. Starting with a historical patient case study, we explore how treatment of this challenging population group has been approached, how an evidence-based framework has informed formulation of a complex health intervention and how this has been progressed via the U.K.'s Medical Research Council (MRC) approach.
