Onset Of Dementia Tied To Depression

Researchers at UC San Francisco have discovered that depression in older patients is far more likely to lead to cases of dementia as the age.

The study tracked nearly 2,500 adults over the age of 70 who did not have any dementia. The cohort was categorized as either having consistent minimal symptoms of depression, moderate and increasing symptoms of depression, and those with high and increasing symptoms of depression.

They were then tracked over the next half-dozen years to determine who developed signs of dementia.

Overall, less than one-eighth of those classified with minimal depressive symptoms developed dementia over the time period, versus 21.4% of those with serious and increasing symptoms. In other words, those in the latter group had a more than 70% higher risk for developing dementia.

The group with moderate and increasing symptoms also had a higher rate of dementia than those with minimal symptoms, but researchers discounted after comparing the cognitive functioning levels of all three groups during the period when they were all free of dementia.

“Our results raise the possibility that older adults’ cognitive health could be improved with interventions to reduce depressive symptoms, such as psychotherapy or other behavioral interventions, or medications,” said lead author Allison Kaup, an assistant adjunct professor at the UCSF psychiatry department and a clinical neuropsychologist at the San Francisco VA Medical Center. “This is an important topic for future treatment studies to investigate.”

One form of dementia, Alzheimer's disease, is the sixth-leading cause of death in the United States, and about 5 million are living with that disease. 

About one in three elderly Americans have Alzheimer's or another form of dementia at the time of their death, and about half of all Americans over the age of 85 have some form of dementia.

In California, about one in five residents of long-term care facilities are being given antipsychotic medications in order to moderate dementia or other behaviors.

“While we cannot rule out that depression may foreshadow dementia as an early symptom, or may be an emotional response to cognitive decline, we found an almost twofold increase among those with high-and-increasing symptoms,” Kaup said. “This suggests that a particular pattern of depressive symptoms may be an independent risk factor. There is a wealth of research showing that a variety of health and lifestyle factors influence cognitive health, such as physical activity and maintaining good cardiovascular health. Likewise, it appears that emotional health is important for cognitive health in aging.”

The study was published in the most recent edition of the journal JAMA Psychiatry.