Recent epidemiological research into the syndromes of unknown aetiology such as irritable bowel syndrome (IBS), dyspepsia, chronic fatigue syndrome and fibromyalgia has moved away from cross-sectional studies since these can teach us little about causality. Prospective studies need to be focused on high-risk populations, and prospective cohort studies of people suffering infection have been performed to assess the biological and psychological risk factors for the later development of IBS and related conditions. In a study by Spence and Moss-Morris published in this issue of Gut (see page 1066), 447 patients with Campylobacter gastroenteritis completed a series of psychosocial questionnaires soon after the laboratory had processed their stool culture.¹ They were followed up at 3 and 6 months after the initial infection and 49 (10%) met the criteria for IBS at both follow-up points. Compared with the remainder, those whose symptoms fulfilled the criteria for modified Rome I (requiring both pain-related symptoms and disturbed defaecation criteria) or Rome II IBS had, at the time of their infection, higher scores on a number of questionnaires. These were: perceived stress, anxiety, somatisation and more negative beliefs about the illness (unlikely to completely resolve, expectation of more persistent complaints). In addition, they had responded during their acute infection by failure to rest and remaining active in spite of their symptoms.

THE PSYCHOLOGICAL MODEL

The authors claim that these findings confirm a theoretical model which suggests that people at risk of IBS have anxious or depressive tendencies together with high and often unrealistic personal expectations (high levels of perfectionism). When faced with an infection such as gastroenteritis, such individuals press on and remain active but this leads to worsened symptoms and they are forced to rest. Resting heightens feelings of anxiety and stress, so they try quickly to return …