Amongst the oldest old (85-plus), depression is frequent and highly persistent, according to a new study from The Netherlands.
Despite its negative consequences, little is known about the natural history of depression in the oldest old. This study, published in the January 2006 issue of the British Journal of Psychiatry, examined the incidence, course and predictors of depression in the general population of people aged over 85.
The Leiden 85-plus Study is a population-based prospective study of a large number of community-dwelling older adults living in Leiden in The Netherlands. Between 1997 and 1999 all those born in 1912-1914 were enrolled in the month of their 85th birthday.
At the beginning of the study, 500 participants were visited by medical staff and research nurses. During these baseline visits, face-to-face interviews were carried out, an electrocardiogram was recorded and blood samples collected.
Follow-up interviews using the Geriatric Depression Scale were carried out for all eligible participants each year during the study period of four years.
It was found that at baseline, 67% of those studied had no significant symptoms of depression. During follow-up, however, the average depression score increased significantly up to the age of 89, and the annual risk for the emergence of depression was 6.8%.
Institutionalisation and poor daily functioning were associated with an increased risk of the development of depression.