Deeply divided ideological positions challenge collaboration when engaging youth with mental disorders, caregivers and providers in mental health research. The integrative dynamics (ID) approach can restructure relationships and overcome 'us vs them' thinking. To assess the extent to which an experience-based co-design (EBCD) approach to patient and family engagement in mental health research aligned with ID processes. A retrospective case study of EBCD data in which transitional-aged youth (n = 12), caregivers (n = 8) and providers (n = 10) co-designed prototypes to improve transitions from child to adult services. Transcripts from focus groups and a co-design event, co-designed prototypes, the resulting model, evaluation interviews and author reflections were coded deductively based on core ID concepts, while allowing for emergent themes. Analysis was based on pattern matching. Triangulation across data sources, research team, and youth and caregiver reflections enhanced rigour. The EBCD focus group discussions of touchpoints in experiences aligned with ID processes of acknowledging the past, by revealing the perceived identity mythos of each group, and allowing expression of and working through emotional pain. These ID processes were briefly revisited in the co-design event, where the focus was on the remaining ID processes: building cross-cutting connections and reconfiguring relationships. The staged EBCD approach may facilitate ID, by working within one's own perspective prior to all perspectives working together in co-design. Researchers can augment patient engagement approaches by applying ID principles with staged integration of groups to improve relations in mental health systems, and EBCD shows promise to operationalize this. © 2020 The Authors Health Expectations published by John Wiley & Sons Ltd.