A new study has untangled the connection between depression and dementia, providing clear evidence that depression is a risk factor for dementia. Prior to this finding, it was unclear to researchers whether depression increased the risk of developing dementia or if dementia led to increased depression.
Researchers screened nearly 1,000 participants and found 125 who had depression, but no signs of neurocognitive decline. Seventeen years later, 22% of participants who were initially depressed had developed dementia, while only 17% of participants who were not depressed developed dementia. The researchers also found a correlation between scores on the depression test and risk of developing dementia. “We have such long follow-up in our study, it lends support to depression as a risk factor for dementia and not merely a consequence,’’ says Jane Saczynski of the University of Massachusetts Medical School who led the study.
Participants came from the Framingham Heart Study, a large study that has been going on since 1948 to look at heart disease risk factors in Framingham, Massachusetts. Using these participants allowed researchers to control for many other risk factors related to dementia.
It is still unclear whether there is a causal relationship between depression and dementia. Further research into the mechanism of the disease is necessary to further understand the connection between depression and dementia. “These findings highlight the importance of thoroughly evaluating newly-diagnosed patients. The next step is to conduct a study to find out if treatment of depression or apathy may delay the onset of dementia,” says Dr. Yonas E. Geda, M.D., a Mayo Clinic neuropsychiatrist who wrote an editorial on the study.