Table 1 Sample case study for intervention

FC, male mid 50's, with poorly controlled type 2 diabetes. He says he understands very little about his diabetes (illness coherence), but that he feels it has a huge impact on his life e.g. he hates taking the medication, he is tired all the time etc (consequences). FC doesn't believe lifestyle factors are important in controlling his illness (control), because he believes the causes of the illness are purely genetic (he believes he inherited the illness from his mother – causal). His wife, MC, believes that while she does not understand the diabetes, her husband understands his diabetes very well (coherence), but that it has very little impact or effect on his life (consequences); She also thinks that he is over-reacting when he complains about it. She believes his diabetes was caused by stress (cause), and if he stopped working so much and took more time to relax, his condition would improve (control). She also does not recognise the importance of lifestyle factors such as diet and exercise for controlling diabetes (control), because she thinks the illness is stress-related and continues to prepare high-fat, high-sugar meals for her husband.

The intervention sessions with this couple could be tailored to focus on clarifying the causal dimension of illness perceptions of both participants, by focusing on the risk factors associated with developing type 2 diabetes. In particular, the importance of lifestyle factors in controlling the illness could be emphasised, and attempts to improve the patient's level of personal control over the illness. The intervention could also focus on highlighting and resolving differences between the patient's and family member's illness perceptions, such as the discrepancy between the perceived consequences and levels of understanding between the patient and his wife. A written, personalised action plan to improve control of the patient's diabetes could then be developed in collaboration with the patient and his wife. This could include, for example, an agreement for the patient and his wife to take time to go out walking together three times a week, to reduce the levels of fatty and sugary foods consumed etc.