Background. The aim of this study was to design a self-report measure of behavioural responses during the acute phase of an illness, in order to assess the importance of these behaviours in the development of ongoing medically unexplained syndromes.

Method. An initial pool of items derived from theoretical models and clinical observation, was piloted on a group of 312 university students to assess the factor structure of the scale and the best fit items. The scale was further validated in a second study of 758 patients who were experiencing Campylobacter gastroenteritis. At 3 months post-infection, patients were sent a second questionnaire assessing symptoms of irritable bowel syndrome (IBS).

Results. Principal components analysis of the items in the student sample yielded a four-factor solution, labelled all-or-nothing behaviour, limiting behaviour, emotional support seeking and practical support seeking. The factor structure was confirmed in the Campylobacter sample, and internal reliability was good. All-or-nothing behaviour was associated with IBS at 3 months post-infection. In contrast, limiting behaviour and practical support seeking at the time of infection appeared to be protective.

Conclusion. The results suggest that this is a valid and reliable measure that can predict the development of a medically unexplained syndrome after acute infection. Overdoing things at the time of infection and then needing to rest for prolonged periods (all-or-nothing behaviour), appears to be a particular risk factor for the development of IBS. Targeted interventions at the time of infection may improve coping and prevent symptoms from becoming chronic.