Temporal relation between depression and cognitive impairment in old age: prospective population based study

OBJECTIVE: To examine the temporal relation between depression and cognitive impairment in old age. DESIGN: Prospective, population based study with four years of follow up. SETTING: City of Leiden, the Netherlands. PARTICIPANTS: 500 people aged 85 years at recruitment. MAIN OUTCOME MEASURES: Annual assessments of depressive symptoms (15 item geriatric depression scale), global cognitive function (mini-mental state examination), attention (Stroop test), processing speed (letter digit coding test), and immediate and delayed recall (12 word learning test). RESULTS: At 85 years old, participants' depressive symptoms and cognitive impairment were highly significantly correlated (P 0.05). CONCLUSION: Caregivers should be aware of the development of depressive symptoms when cognitive impairment is present. However, the presence of depression only does not increase the risk of cognitive decline.