Uncovering factors that drive depression after a stroke

After a stroke, many people develop depression that is driven by factors including cognitive difficulties, a lack of social participation, and self-perceived poor recovery. This depression can persist for months or years, according to a new study from Georgetown University Medical Center and MedStar Health researchers.

Somewhat contrarily, physical disability after a stroke, which has been related to depression symptoms in other studies, was not related to depression in stroke survivors in this study.

The study’s findings were presented at the 62nd Annual Meeting of the Academy of Aphasia in Nara, Japan, on October 20.

In the study, researchers focused on people with a history of aphasia, which is a loss of ability to communicate due to damage in the brain’s language centers.

“Depression is extremely common after a stroke, occurring in about a third to half of all stroke survivors, but we found that the reasons people develop depression differ depending on the kinds of difficulties that develop after their strokes,” says the study’s senior author Peter E. Turkeltaub, MD, Ph.D., director of the Cognitive Recovery Lab and the Aphasia Clinic at MedStar National Rehabilitation Hospital, Washington, DC.

“Most research on depression after stroke focuses on the first few months of recovery and often excludes people with aphasia. We focused specifically on people with aphasia in the chronic phase of stroke recovery, which can last for many years.”

Annually, about 800,000 people in the U.S. have strokes, which disproportionately affects Black people. For this study, the researchers queried 93 people who had a stroke that was mostly mild to moderate, and a few that were severe. Forty percent of the people in the study were Black.

Stroke recovery is fastest early on and slows down over time, so the researchers focused on people at least six months after their stroke; many enrollees had their stroke years ago. “That is when most people are trying to reintegrate into life with varying degrees of success,” says Turkeltaub.

The comparison study group consisted of 70 people of similar demographics who had not had a stroke. All 163 study participants, who were a mean age of 60, completed a depression survey to rate the severity of depressive symptoms. Stroke survivors also completed a survey aimed at assessing perceived disabilities and health-related quality of life.

The researchers developed two statistical models based on the survey responses in order to explore the relationship between stroke and depression. Their first model demonstrated that stroke survivors had higher depression scores than controls, but also found that younger and better educated stroke survivors reported less depression.

In their second model, cognitive and communication disabilities, social participation and self-perceived stroke recovery scores predicted depression levels, but physical disability scores or language and motor disability measures were not predictive of depression.

“Understanding the root causes of depression can lead to better care for those recovering from a stroke,” Turkeltaub adds. “While they may have new disabilities because of a stroke, ensuring patients have the best quality of life possible is always our goal. In particular, our study is one of the few that provides information on how living with aphasia impacts depression symptoms, which we hope will help doctors, psychologists and speech therapists provide the best care for stroke survivors.”

The investigators focused on left hemisphere strokes that often result in communication difficulties such as aphasia. Strokes on the right side are more often related to general cognitive difficulties. Because the difficulties experienced by stroke survivors are so different depending on which hemisphere was affected, Turkeltaub says it makes sense that reasons for depression might differ depending on the hemisphere of the stroke.

The scientists have started to look at whether damage to particular brain structures or networks relate to depression symptoms. “Prior research suggests that dysfunction in large-scale brain networks causes post-stroke depression, so we’re currently looking at this area more closely,” says Turkeltaub.