Research indicates that long-term depression from young adulthood negatively impacts cognitive function by middle age, with greater effects seen in black adults, possibly explaining some disparities in dementia risk. Credit: SciTechDaily.com
The study involved 3,117 people with an average age of 30 at the start of the study. Of participants, 47% were black and 53% were white.Participants were evaluated for depressive symptoms every five years for 20 years. At each visit, they completed a questionnaire asking if they experienced changes in appetite or sleep, had problems with concentration or experienced feelings of worthlessness, sadness, or loneliness. Higher scores represented more symptoms.
For example, on a test that measures processing speed and memory, participants were given a key showing numbers and corresponding symbols. They then had to draw those symbols on a separate list of random numbers as quickly as possible. The score range was zero to 133 with lower scores representing worse cognition.
Researchers found among white participants, those in the high symptom group had worse verbal memory and processing speed scores when compared to those in the low symptom group.“Our results suggest that black adults are not only more likely to experience worse depressive symptoms trajectories, but these symptoms may lead to worse repercussions on thinking and memory as early as middle age,” said Grasset. “This may help explain some of the disparities in dementia risk at older age.