Background. Depression is considered to be a major health problem in the el
derly. Due to methodological problems, there are few studies on the inciden
ce of depression in old age. The present study examines the prevalence of d
epression In a 3-year follow-up study of a non-depressed very elderly popul
ation, thus estimating the incidence.
Methods. 875 non-depressed persons with a mean age of 85 years were extensi
vely examined by physicians twice with a 3-year interval. Depression diagno
sis was made according to DSM-IV. All persons with a history of depression
or a current depression were excluded in order to estimate the first incide
nce.
Results. 4.1% of the population was diagnosed as having a depression at the
follow-up examination. The estimated first incidence was 1.4% per person y
ear (0.8% in males and 1.5% in females). Characteristics at baseline correl
ated with the onset of depression were: having a dementia, insufficient soc
ial network and having more than two depressive symptoms.
Conclusions. The incidence of depression was slightly lower in this very el
derly population than for younger age groups, but followed the same female
to male ratio. (C) 1999 John Wiley & Sons, Ltd.