New evidence furthers link between depression and stroke
For several years researchers have detected a consistent correlation between depressive symptoms and an increased risk of stroke. A new US study is offering more evidence of the link, presenting data from a longitudinal research project investigating whether race factors into the depression/stroke relationship.
It has been challenging for researchers to understand the frequently observed link between depression and stroke risk. It would be fair to hypothesize the link to be underpinned by other more causal stroke risk factors. For example, depression can prompt unhealthy behaviors that amplify the risk of developing conditions such as diabetes and hypertension, which certainly increase a person’s risk of stroke.
A 2012 meta-analysis suggested the effect of depression on stroke risk was, “probably independent of other risk factors, including hypertension and diabetes.” An even more focused systematic review in 2014 further confirmed the idea that depression can increase stroke risk, independent of any, “clinically apparent cerebrovascular and cardiovascular diseases.”
Further evidence of some kind of neurophysiological relationship between depression and stroke is seen in a condition called post-stroke depression. One in three stroke patients are characterized with post-stroke depression, a condition that can increase post-stroke risk of death by up to 10 times.
“There are a number of well-known risk factors for stroke, such as high blood pressure, diabetes and heart disease; but we are beginning to understand that there are nontraditional risk factors as well, and having depressive symptoms looms high on that list,” explains senior author on the new study, Virginia Howard.
The new research comes out of a longitudinal study called Reasons for Geographic and Racial Differences in Stroke (REGARDS) that began back in 2003. One of the goals of the project was to understand whether depression plays a role in the higher rates of stroke in black populations in the United States.
In the new study depressive symptoms were measured in the almost 25,000 subjects using a scale known as CES-D-4, which offers a depression score of between 0 and 12. Scores above four on the scale are generally considered to indicate depressive symptoms.
Across the average nine-year follow-up those subjects scoring between one and three on the depression scale were 39 percent more likely to suffer a stroke, compared to those in the cohort with no reported depression, while those scoring four or more on the scale were 54 percent more likely to suffer a stroke.
Perhaps most importantly, the study saw no difference in the depression and stroke risk association between different racial groupings. This suggests symptoms of depression can be considered an independent risk factor for stroke, across diverse racial and ethnic populations.
Howard suggests what all this means is that doctors should recognize depression as a significant risk factor for stroke, and evaluations of depression, in relation to stroke risk, should be considered in routine patient health screenings.
“The standard questions asked in the typical physician/patient encounter need to be updated to include questions regarding depressive symptoms,” says Howard. “Physicians in primary care, internal medicine and geriatrics need to consider asking their patients about depressive symptoms.”
The new study was published in the journal Neurology: Clinical Practice.