Depression is on the rise, especially among younger adults and teens. And new research suggests it is more imperative than ever to ensure that depression is managed during early adult years, as depressive symptoms have been found to increase risk for cognitive impairment and dementia later in life. A new study indicates that poor emotional/mental health may take its toll on cognition.
The new research adds to a growing body of evidence that links depression with dementia, but while most studies have pointed to its association in later life, the study shows that depression in early adulthood may lead to lower cognition 10 years later and to cognitive decline in old age.
In the study, the researchers used innovative statistical methods to predict average trajectories of depressive symptoms for approximately 15,000 participants ages 20 to 89, divided into three life stages: older, midlife and young adulthood. They then applied these predicted trajectories and found that in a group of approximately 6,000 older participants, the odds of cognitive impairment were 73 percent higher for those estimated to have elevated depressive symptoms in early adulthood, and 43 percent higher for those estimated to have elevated depressive symptoms in later life.
For depressive symptoms in midlife, the researchers found an association with cognitive impairment, but this was discounted when they adjusted for depression in other life stages.
"Several mechanisms explain how depression might increase dementia risk," said first author Willa Brenowitz, PhD, MPH, of the UCSF Department of Psychiatry and Behavioral Sciences and the Weill Institute for Neurosciences. "Among them is that hyperactivity of the central stress response system increases production of the stress hormones glucocorticoids, leading to damage of the hippocampus, the part of the brain essential for forming, organizing and storing new memories."
Other studies have linked depression with atrophy of the hippocampus, and one study has shown faster rates of volume loss in women, she said.
In estimating the depressive symptoms across each life stage, researchers pooled data from younger participants with data from the approximately 6,000 older participants and predicted average trajectories. These participants, whose average age was 72 at the start of the study and lived at home, had been enrolled by the Health Aging and Body Composition Study and the Cardiovascular Health Study. They were followed annually or semi-annually for up to 11 years.
Study participants were screened for depression using CESD-10, a questionnaire assessing symptoms in the past week. Moderate or high depressive symptoms were found in 13 percent of young adults, 26 percent of midlife adults and 34 percent of older participants; 1,277 participants were diagnosed with cognitive impairment following neuropsychological testing, evidence of global decline, documented use of a dementia medication or hospitalization with dementia as a primary or secondary diagnosis.
"Generally, we found that the greater the depressive symptoms, the lower the cognition and the faster the rates of decline," said Brenowitz, who is also affiliated with the UCSF Department of Epidemiology and Biostatistics. "Older adults estimated to have moderate or high depressive symptoms in early adulthood were found to experience a drop in cognition over 10 years."
If you are a younger adult, you can take control of your mental health status by working with your caregiver to adopt a healthier lifestyle, and also find the right counselor who will teach you tools to avoid depression risks. Take whole foods supplements such as Fucosea, and natural supplements to help you relax and unwind, such as Oysrelax. At Herbsea, we are your partner in good health and supporting your happiness!
Brenowitz WD, et al. “Depressive Symptoms Imputed Across the Life Course Are Associated with Cognitive Impairment and Cognitive Decline.” Journal of Alzheimer's Disease, 2021; 1 DOI: 10.3233/JAD-210588