In this multivariate analysis of the irritable bowel syndrome (IBS) we describe the symptomatic and psychologic features of the condition and their possible contributions to health care seeking. We studied 72 IBS patients, 82 persons with IBS who had not sought medical treatment, and 84 normal subjects. All subjects received complete medical evaluation, diary card assessment of abdominal pain and stool habit, and standard psychologic tests of pain, personality, mood, stressful life events, illness behavior, and social support. Pain and diarrhea were the most important symptoms associated with patient status. When controlling for these symptoms we found that (a) IBS patients have a higher proportion of abnormal personality patterns, greater illness behaviors, and lower positive stressful life event scores than IBS nonpatients (p less than 0.001) and normals (p less than 0.001); (b) IBS nonpatients, although psychologically intermediate between patients and normals, are not different from normals (p less than 0.21); and (c) IBS nonpatients have higher coping capabilities, experience illness as less disruptive to life, and tend to exhibit less psychologic denial than patients. These factors may contribute to "wellness behaviors" among people with chronic bowel symptoms. We conclude that the psychologic factors previously attributed to the IBS are associated with patient status rather than to the disorder per se. These factors may interact with physiologic disturbances in the bowel to determine how the illness is experienced and acted upon.