Worsening Depressive Symptoms Linked to Dementia

Older adults with depressive symptoms that worsen over time have a higher risk for developing dementia, according to new research from the Netherlands.

Previous research has linked depression in older adults to incident dementia by assessing a single point in time. However, this study aimed to assess the long-term course of depression and its effect on the risk of dementia.
________________________________________________________________________________________________________________________________________________________________________

RELATED CONTENT
Can Exercise Prevent Depression?
Collaborative Care Significantly Improves Depression Outcomes
________________________________________________________________________________________________________________________________________________________________________

To conduct their study, the researchers continuously measured depressive symptoms over a 10-year period in adults aged 55 years or older who participated in the Rotterdam Study in the Netherlands.

Participants did not have dementia at baseline but had reported depressive symptoms during at least 1 examination round (1993-1995, 1997-1999, or 2002-2004).

The researchers used the Dutch version of the Center for Epidemiology Depression Scale (CES-D) and the Hospital Anxiety and Depression Scale-Depression to assess depressive symptoms.

During the study period (1993-2004), the researchers followed 3325 participants and identified 5 trajectories of depressive symptoms: maintained low CES-D scores; moderately high starting scores but then remitting; low starting scores, increasing, then remitting; low starting scores that steadily increased; and maintained high scores.

The researchers found that the trajectory that included participants with steadily increasing depressive scores was the only one associated with an increased risk of dementia, compared with those with low depressive symptoms and after adjusting for incident stroke, restricting to Alzheimer disease as an outcome, and accounting for mortality as a competing risk.

“Risk of dementia differed with different courses of depression, which could not be captured by a single assessment of depressive symptoms,” the researchers concluded. “The higher risk of dementia only in the increasing trajectory suggests depression might be a prodrome of dementia.”

—Amanda Balbi

Reference:

Mirza SS, Wolters FJ, Swanson SA, et al. 10-year trajectories of depressive symptoms and risk of dementia: a population-based study [published online April 29, 2016]. Lancet Psychiatry. http://dx.doi.org/10.1016/S2215-0366(16)00097-3.