Complex illness behaviour can be seen as a product of dysfunctional communication between doctors and patients. A methodology to understand such behaviour is described: it uses case record analysis and meetings with patients and health teams to create a set of family trees and graphs of consultation patterns; these are the basis on which to generate and test hypotheses. This model is used to explore the consultation rates of a family between the 1940s and 1988. Illness behaviours increased rapidly during the 1980s at a time when both the family and their general practitioners were undergoing rapid changes and losing significant members. Mutually unacknowledged depression may have been a key factor. Strategies for change are suggested.