Study Shows Late-Life Depression Increases Risk of Future Cognitive Impairment

Given the unprecedented projected growth in the number of older adults in the United States and abroad, identifying potentially treatable contributors to late-life cognitive impairment is imperative. A number of studies have found an association between depression later in life and a subsequent diagnosis of mild cognitive impairment and dementia, but whether depression is a risk factor for cognitive decline—rather than a consequence of it—has remained a key question.

A rigorous new study that followed 6376 older women enrolled in the Women’s Health Initiative Memory Study for more than 5 years suggests that late-life depression can be a risk factor for future cognitive impairment, a finding that has important ramifications for older adults, particularly those residing in long-term care. The new study, led by Joseph S. Goveas, MD, of the Medical College of Wisconsin, was published in the Journal of the American Geriatrics Society (JAGS) in January (https://bit.ly/WHIMS-Goveas). The study, which is the largest one to date to examine possible links between depression and cognitive impairment, has many strengths. The women, aged 65 to 79 years when they enrolled in a trial of postmenopausal hormone therapy, underwent extensive screening.

Goveas and colleagues used a highly sensitive and specific screening tool to identify those with depressive disorders, and they used extensive neuropsychiatric examinations and careful clinical diagnosis to identify cases of mild cognitive impairment and probable dementia. The researchers discovered that 8% of the women had clinically significant depressive symptoms at study entry, and that these individuals had roughly twice the risk of mild cognitive impairment as those who did not suffer from depression, after adjustment for confounders. Women withdepressive symptoms also ran twice the risk of developing probable dementia as those who did not have depressive symptoms. Interestingly, these odds were not affected by baseline cognitive function or history of hormone therapy use.

The overall prevalence of dementia in adults 71 years and older is roughly 11%, and research suggests that the incidence among long-term care residents is significantly higher. These new findings highlight the pressing need to identify and treat depression in this vulnerable population. Helping the relatives of residents to recognize the likely signs and symptoms of depression and to understand the importance of reporting these signs and symptoms is imperative.

To raise awareness of the benefits of recognizing and treating depressive symptoms in later life, the American Geriatrics Society’s Foundation for Health in Aging (FHA) has published an easy to understand summary of the JAGS study at https://bit.ly/WHIMS-AGS-Summary. The FHA’s public education Website also includes information about depression in later life and how to recognize it, which is available at https://bit.ly/FHADepression.