Stefan Elbers

117 Co-designing relapse prevention strategies INTRODUCTION Only a fraction of intervention development projects is able to bridge the translational gap from scientific research to clinical practice (Bero et al., 1998; Chambers, 2018; Czajkowski et al., 2015; de la Vega & Miró, 2014). An important factor for this limited uptake may be that contextual factors, such as stakeholder acceptability or implementation in existing practices, receive little attention during earlier development stages (Bowen et al., 2009). For example, many intervention development guidelines emphasize the formulation of an underlying theoretical construct and subsequent experimental testing to validate each assumed causal step, but only address implementation and feasibility after the intervention development phase has been completed (Craig et al., 2008; Kok et al., 2004; Sheeran et al., 2017). Consequently, theoretically sound interventions may be discarded due to insufficient attention to crucial translational factors such as low perceived utility by patients or health care providers (HCPs), inconvenient navigation, or a discrepancy between the intervention requirements and patients’ preferences (Bishop et al., 2015; Damschroder et al., 2009; Hermsen et al., 2017; Murray et al., 2010; Robert & Macdonald, 2017; Tarquinio et al., 2015). An opportunity to increase the emphasis on these factors is to incorporate co-design methods. Co-design not only is characterized by an incremental knowledge over multiple development cycles (Stappers & Giaccardi, 2017) but also specifically emphasizes empathizing with each stakeholder, integrating conflicting requirements, and quickly transitioning ideas to testable prototypes. Co-design differs from other design methodologies in that it involves a range of tools and exercises to optimize collaboration between professional designers and people who are not trained in the design process, such as patients and therapists (Steen, 2008). Done rightly, co-design brings together different views, input, and competencies of people with a variety of perspectives to address a specific problem (Bradwell & Marr, 2017; Donetto et al., 2015). As a result, this approach should increase the acceptability and integration of the intervention in existing clinical practice by accommodating relevant contextual factors that have been identified by stakeholders in the development process. Although co-design is increasingly adopted in the development of health care interventions (e.g. Boyd et al., 2012; Donetto et al., 2015; Iedema et al., 2010; Jamin et al., 2018; Revenäs et al., 2015; Visser et al., 2005), prior studies have indicated that effective co-design is not without its challenges. For example, the process of engaging all stakeholders can be time-consuming and intensive. This can be particularly difficult in the context of health care because HCPs generally have a high workload (i.e.dema et al., 2010), and participating patients often do not directly benefit from the development projects,which could negatively