Symptoms of depression that steadily escalate during later life are associated with development of dementia. But depression that follows a different course, such as spiking and then remitting, does not appear to have this association, according to a new investigation.
The study, published in the July 2016 issue of the Lancet Psychiatry was conducted in 3,325 men and women 55 or older in the Netherlands, all of whom had a history of depression but not of dementia. In three rounds of examinations during an 11-year period, investigators measured depressive symptoms with standardized tests and screened participants for dementia; they also used physicians’ digital medical records to follow participants. Investigators identified five courses of depressive symptoms: low, decreasing, remitting, increasing, and high.
The analysis showed that only those whose depressive symptoms steadily increased were at significantly higher risk of developing dementia, particularly after the first three years of the study. This finding did not change after adjustment for independent risk factors for dementia, such as age or being an APOE4 gene carrier.
The investigators concluded that persistently worsening symptoms of depression in older age are often a precursor of dementia but depression that resolves or improves over time is not. Keep in mind, however, that this was an observational study and does not prove that escalating depression definitely causes dementia.
If you are concerned that you or a loved one experiences this pattern of depressive symptoms, talk to your doctor about getting an evaluation.