Prognosis of depression in old age

Summary stic significance of depression in terms of survival and cognitive decline was investigated in a prospective study of random persons of four age co-horts (65-, 75-, 80-, and 85-years, N = 1330) using mini-mental state examination (MIMSE), self-reported depression scale of Zung, clinical dementia rating (CDR), DSM-III criteria of major depression, clinical depression (CD), and the date and causes of death during the five-year follow-up. The Zung-score (> 40), and CD were associated with increased five-year mortality in the age groups of 65, 75 and 80 years. After controlling for age and gender, an increase in Zungscore by one point predicted a 3 % higher mortality risk (p < 0.001). CD was associated with a 40 % increased mortality risk. After further controlling MMSE score, the Zung-score over 45 still increased the risk of death (hazard rate = HR: 1.66 (1.21–2.29)). The risk remained significantly increased after additional adjustment for clinical comorbity (1.58). Excess mortality increased over time. Cognitive decline was studied using CDR at re-examination of 821 subjects after five years. Age predicted cognitive decline and after controlling for age, MMSE score (<24) predicted cognitive decline (HR 2.49). In subjects without impaired cognition at entry, age and comorbidity predicted cognitive decline, but CD and the Zung-score lost their prognostic significances. The data indicate that lowered mood measured with the Zung-test is an independent risk indicator of death in the general aged population, but depression hardly is an independent risk condition of cognitive decline.