Research Review

Depression May Nearly Double Risk of Dementia

A new study shows that having depression may nearly double your risk of developing dementia later in life. The research is published in Neurology.

For the study, researchers examined research data on 949 people with an average age of 79 from the Framingham Heart Study. At the start of the study, participants were free of dementia and were tested for depressive symptoms based on questions about general depression, sleep complaints, social relationships, and other factors. A total of 125 people (13%) were classified as having depression at the start of the study. The participants were followed for up to 17 years.

At the end of the study, 164 people had developed dementia with 136 specifically diagnosed with Alzheimer’s disease. Nearly 22% of people who were depressed at the start of the study developed dementia compared with about 17% of those who were not depressed, a 70% increased risk in those who were depressed. The 10-year absolute risk for dementia was 0.21 in people without depressive symptoms and 0.34 in people with depressive symptoms. The results were the same regardless of a person’s age, sex, education, and whether they had the APOE gene that increases a person’s risk of Alzheimer’s disease.

“While it’s unclear if depression causes dementia, there are a number of ways depression might impact the risk of dementia,” says study author Jane Saczynski, PhD, with the University of Massachusetts Medical School in Worcester, MA. She hopes the study, which is one of the largest and longest population based studies to date, helps clear up confusion over earlier studies that reported inconsistent results about the link between depression and dementia.

— Source: American Academy of Neurology