The study began with the systematic clinical evaluation of a cross-section of 500 of the clinic's patients. This was followed by a 'blind' follow-up of the index subjects and a 'blind' study of first-degree relatives. The present report deals with the diagnosis of Briquet's syndrome (hysteria, somatisation disorder) at index, at follow-up, and among first-degree relatives. The data indicate that the criteria used for the diagnosis of Briquet's syndrome select patients who show a high degree of diagnostic consistency over many years, although not all patients who meet these criteria at follow-up receive the diagnosis of Briquet's syndrome initially. Most importantly, the diagnostic criteria select cases associated with a strong familial increase in the risk of Briquet's syndrome and in the risk of antisocial personality. Both are increased among first-degree female relatives, while only antisocial personality is increased among first-degree male relatives.