The natural history of mental disorder in old age. A long-term study

In a prospective study, 153 consecutive new referrals to a psychogeriatrician in Oxfordshire in 1973 were followed up for 15 years. The percentage of the over-65 population at risk was 0.27 and, of those aged over 80, 0.6. Alzheimer's dementia and depressive illness comprised over two-thirds of referrals. A quarter became permanent admissions, half of them with Alzheimer's dementia, 19% of whom were alive five years later. Depressive illness, at ten years, had a mortality 1.2-1.6 times that of the population at risk. The distinction between Alzheimer's dementia and depressive illness, based on their natural history and causes of death, was reinforced.