Health care researchers and practitioners are increasingly asked to work across disciplines (or, in keeping with the conference theme, "Between the Tides") to deal with complex health issues. But working with individuals from different fields is more challenging than it sounds. Working across disciplines can result in tension and miscommunications. Furthermore, to explore interactions among disciplines requires breaking down disciplinary boundaries and creating a common framework and language to define, analyze, and develop new approaches. This paper explores the benefits and challenges of teaching transdisciplinarity in a discipline-centred world, including a description of the journey of one post-graduate research training program as it strives to help student researchers break down disciplinary borders and develop a common framework to approach a particular health issue--in this case, the problem of substance misuse and addictions.