A sample of 46 schizophrenic patients (26 men and 20 women) from a night clinic (N subjects) with an average age of 21.7 years at the time of first manifestation of the illness and a sample of hospital inpatients (H subjects) matched for diagnosis, sex, and age were followed up from 1971/1973 to 1983. The average age of the patients in 1983 was 40 years. The course of the illness and the pattern of hospitalization were investigated by personally questioning each patient and by scrutinizing all the case history records and other relevant documents; for each clinical cycle of illness, consisting of an overt phase followed by a quiescent interval, a case control sheet was filled out. The duration of illness was 18 years for the N subjects and 15 years for the H subjects. Longitudinal analysis of these years of illness in both patient samples showed a marked decrease in the number and duration of overt phases and stays in hospital, but a progressive aggravation of residual symptomatology during quiescent intervals and a progressively decreasing ability to work and earn a living. Covariance analysis (multiple classification analysis) with four covariables (age at first manifestation of the illness; residual symptomatology during quiescence in the first 4 years of illness; duration of overt phases in the first 4 years; length of hospital stays until actual or fictitious admission to the night clinic) showed no significant differences between the course of the illness in the 2 patient samples, but it did reveal a significantly greater reduction in the night clinic patients’ total duration of hospitalization, so that in their case the night clinic evidently served as a substitute for hospital treatmen