Objective: Our aim was to identify factors that distinguish persons with fibromyalgia who have obtained medical treatment at a tertiary care practice ["patients"] from those who have not sought treatment ["non-patients"] and from healthy controls. Results: Patients, relative to non-patients, show significantly lower pain thresholds at tender and control points, report significantly greater symptoms severity and disability, and meet criteria for a significantly greater number of lifetime psychiatric diagnoses. Both patients and non-patients display significantly lower pain thresholds than controls. However, non-patients do not differ from controls in psychiatric comorbidity. Conclusions: Our understanding of fibromyalgia has been limited by studies of patients as tertiary care practices with high levels of symptom severity and psychiatric morbidity. Evaluation of non-patients suggests that psychological distress is not a primary feature of fibromyalgia. © 1994 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.