OBJECTIVE: The present research attempts to add to the existing body of data on the course of schizophrenia by comparing the findings of a prospective study of a group of U.S. schizophrenic patients with data from two European studies. METHOD: Seventy-four U.S. patients given the diagnosis of schizophrenia according to Research Diagnostic Criteria were longitudinally assessed at hospitalization and at three intervals up to 10 years after illness onset. The longitudinal criteria for type of onset, course of illness, and outcome were derived from the European studies of Manfred Bleuler and Luc Ciompi. The type of onset, course of illness, and outcome of the U.S. patients were compared with those of the patients in the two European studies. RESULTS: A lower rate of acute onset and of episodic illness was found in the U.S. patients, but the relative frequency of a number of major overall course patterns was similar across studies. CONCLUSIONS: Despite many potential threats to comparability, the results of the European and U.S. longitudinal studies of the course of schizophrenia were fairly congruent in terms of the relative rate with which patients fell into the categories established by Bleuler and Ciompi. These results are encouraging in that they point to the possibility of estimating the rate of occurrence of particular expressions of the overall course of schizophrenia.Abstract Teaser