In discussing current trends in mental hospital statistics, it is convenient to make a distinction between patients who have been resident for more than two years (the longstay group) and short or medium stay patients. The chances of discharge, once an individual has been resident for two years, are low and become progressively lower the longer he stays. In mental hospitals in England and Wales from 70 to 80 per cent. of patients are longstay; and the majority of these are diagnosed as schizophrenic (75 per cent. in 1954), although no more than one-third of newly admitted patients are given this diagnosis. There has been a consistent tendency over the past 30 years for a decreasing proportion of schizophrenic patients to be retained continuously for two years after admission—for example, about 60 per cent. of schizophrenics admitted in 1930 were retained in this way, compared with 30 per cent. in 1950 (Brown, 1960). Since then there have been important changes in social treatments and administrative policies, and the major tranquillizers have been introduced. The proportion of schizophrenics retained for two years or more has now approached 10 per cent. at many hospitals (Brown, 1959; Wing et al., 1959). However, very little is known in numerical terms about the extent to which the patients have to be readmitted to hospital once they have been discharged. The only satisfactory studies of the readmission of schizophrenic patients were made before the introduction of the recent changes in discharge policy, and dealt with admission cohorts in which the proportion retained for two years ranged from 60 to 30 per cent. (e.g. Freyhan, 1958; Shepherd, 1957). Reduction within this range did not appear to lead to an increased risk of readmission. However, the possibility cannot be dismissed that a further reduction would lead to the discharge of patients with a special liability to relapse and readmission.