We undertook a longitudinal qualitative study involving of 20 patients from Scotland who had type 2 diabetes. We looked at their perceptions and understandings of why they had developed diabetes and how, and why, their causation accounts had changed or remained stable over time. Respondents, all of whom were white, were interviewed four times over a 4-year period (at baseline, 6, 12 and 48 months). Their causation accounts often shifted, sometimes subtly, sometimes radically, over the 4 years. The experiential dimensions of living with, observing, and managing their disease over time were central to understanding the continuities and changes we observed. We also highlight how, through a process of removing, adding and/or de-emphasising explanatory factors, causation accounts could be used as "resources" to justify or enable present treatment choices. We use our work to support critiques of social cognition theories, with their emphasis upon beliefs being antecedent to behaviours. We also provide reflections upon the implications of our findings for qualitative research designs and sampling strategies.