OBJECTIVE Little is known about the natural history of functional GI symptoms, including what factors influence GI symptom patterns and health care seeking for them over the long term. We aimed to determine whether psychological factors play a role in the development and long-term course of these symptoms. METHODS A random sample of community subjects (n = 361) who reported having unexplained abdominal pain for > or =1 month in a previous population survey were included in the study. Controls (n = 120) were defined as not having abdominal pain for > or =1 month from this initial survey. Subjects were prospectively followed up via a questionnaire every 4 months over a 12-month period. The questionnaire asked about the presence of GI symptoms over the past week and psychological distress over the past 3 wk (psychological caseness being defined as a score of > or=2 of 12 on the General Health Questionnaire). The number of visits made to a physician or medical specialist over the past 4 months was evaluated. RESULTS GI symptoms were common among community controls and subjects with abdominal pain. Similar onset and disappearance rates were observed for the majority of GI symptom categories, accounting for the stability of the prevalence rates over a 1-yr period. Changes in a state measure of psychological distress were not significantly associated with changes in GI symptom status between the 4- and 8-month (r = 0.14, p = 0.08) and 8- and 12-month (r = 0.02, p = 0.77) follow-ups. Baseline psychological distress, however, was an independent predictor of having persistent GI symptoms, including abdominal pain, bloating, and constipation, and frequently seeking health care for GI symptoms over 1 yr. CONCLUSIONS Psychological distress levels do not seem to be important in explaining GI symptom change over a 1-yr period. Psychological distress, however, is linked to having persistent GI symptoms and frequently seeking health care for them over time. Clinicians should consider psychological factors in the treatment of this subset of irritable bowel syndrome patients.