Depressive symptoms not found to increase risk of dementia

Whitehall II data on depressive symptoms over 28 years show that depressive symptoms in later life were significantly associated with development of dementia. However, depressive symptoms in midlife, even when chronic or recurring were not significantly associated with development of dementia. 

Thus, there is no support for the hypothesis that depressive symptoms increase dementia risk; our findings are consistent with the hypothesis that depressive symptoms are a prodromal feature of dementia or that the two share common causes.

The study has been published by the  Journal of the American Medical Association:

Trajectories of Depressive Symptoms Before Diagnosis of Dementia. A 28-Year Follow-up Study. Archana Singh-Manoux; Aline Dugravot; Agnes Fournier; Jessica Abell;Klaus Ebmeier; Mika Kivimäki; Séverine Sabia. JAMA Psychiatry, May 2017. Published online May 17, 2017

Some links to media coverage stories:

Express: http://www.express.co.uk/life-style/health/806362/depression-dementia-symptoms-cause

MedScape: http://www.medscape.com/viewarticle/880147

MedPage Today: https://www.medpagetoday.com/neurology/dementia/65414

Managed Health Care: http://www.managedhealthcareconnect.com/content/depressive-symptoms-begin-rising-about-decade-dementia-diagnosis