SummaryThe study at Graylingwell Hospital conducted by Roth (1955) has in part been replicated in order to study the changing patterns of mental illness in the elderly over a 25-year period. Important changes in the diagnostic distribution and outcome of cases admitted have occurred. Functional illness has given way to dementia, not as a proportion of patients admitted but in the number of beds employed for their care 6 and 24 months after their index admission. Discharge rates for all diagnostic groups except acute confusional states, have undergone considerable change and death rates have fallen. The study has concentrated on the residual in-patient population, paying particular attention to increasing demand for beds for the dementing group. These changes have been quantified and reflect a four-fold increase in bed requirements for cases of dementia at two years. Despite a striking reduction in requirement for functional cases, there is an overall increase in bed requirement of 38 per cent at the two-year mark.