Four Groups of patients, each consisting of 1,000 consecutive first admissions to the Pennsylvania Hospital, have been followed for 5 years from the time of their first admission to a psychiatric hospital. The sample covers a span of more than 30 years in general psychiatric hospital experience in a large metropolitan area on the east coast. Tables show a decrease in death rates and in number of patients continuously hospitalized, with a relatively constant suicide rate. There has been a somewhat uniform readmission rate, but a tendency toward shorter duration of first admissions. The readmission and chronicity rates for the functional psychoses have been decreasing.Among the more important factors influencing the mortality rates are the introduction of more specific therapies for paresis in the late 1920's, chemotherapy in the late 1930's, antibiotics in the mid-1940's, and constantly improving standards of nursing and ancillary care throughout the whole period. Duration of stay has been influenced by changing policies regarding discharge, the use of somatic therapies, and increasing emphasis on the hospital as a therapeutic milieu. These factors favoring earlier discharge have not resulted in an increased readmission rate; on the contrary, the readmission rate for the functional psychoses has been lowered. When the total sample of patients is considered, fewer are dying in the 5 year period, more are leaving the hospital sooner, and about the same percentage is returning as in the early 1920's.Abstract Teaser