The Gospel Oak Study: prevalence rates of dementia, depression and activity limitation among elderly residents in inner London.

The steps to setting up a population register of elderly residents are described. Based upon this, 87.2% of the elderly residents of an inner-city electoral area were screened for memory disorder, depression and activity limitation using the Short CARE. Contact with medical and social agencies was also recorded; 4.7% were classed as cases by the dementia diagnostic scale, sufferers being older and not living alone. Of the residents 15.9% were classed as depressed, this state being more prevalent in those not currently married. The depressed were, in contrast to the demented residents, likely to be in recent contact with hospital and general practitioner. Thirty-two per cent of the population showed impairment in daily activity, these individuals were usually older, not married and receiving hospital care. Sleep disorder and complaint of many somatic symptoms were associated with a diagnosis of depression. In contrast, most respondents with a subjective complaint of memory disorder, which was common in this population, were neither suffering from depression nor dementia. With this accurate sampling frame and a good response rate, the prevalence rate of clinical depression must be seen as disturbingly high. The prevalence rate of dementia approximated to that of other surveys. This study also indicated that general practitioners' lists may be inaccurate and that non-responders to first approaches for interview, although similar in demographic features to those responding, may contain among them many suffering from dementia.