Clinical Context

Depression is common among patients with stroke, with cumulative incidence 39% to 52% within 5 years of stroke and risk 2- to 8-fold higher than in a reference population; however, depressive symptom trajectories before and after stroke are still unclear.

Although increased depressive symptoms after stroke may reflect psychological reaction to stroke and associated disability, or stroke-induced brain damage, high depression rates among stroke survivors may partly reflect changes preceding stroke. Recent studies have shown depression to be an independent risk factor for stroke incidence.

Study Synopsis and Perspective

Whereas symptoms of depression are known to intensify in patients who have recently experienced an incident stroke, it might also be true in such cases that the depression actually starts to worsen in the months or years before the stroke occurs, suggests a new study of adults 50 years and older.

"Stroke seems to alter the course of depressive symptoms in more complex ways than previously thought," Maria Blöchl, PhD, University of Münster, Germany, told Medscape Medical News.

"As commonly thought, depressive symptoms surge after stroke and remain elevated for several years. But we also showed that depressive symptoms slightly increase before the stroke, perhaps indicating incipient stroke," said Blöchl, who is lead author on the study published online July 13 in Neurology, with coauthor Steffen Nestler, PhD, also from the University of Münster.

About 30% of stroke survivors might experience depression at any time after the acute event. The cumulative incidence within 5 years hovers around 39% to 52%, yet little is known about how changes in depressive symptoms unfold before and after incident stroke, the report states.

To investigate, Blöchl and colleagues identified the trajectory of depressive symptoms several years before and after incident stroke in 10,797 adults (mean age, 65 years; 55% women) from the English Longitudinal Study of Ageing (ELSA), an ongoing longitudinal cohort study.

The 425 case participants (3.9%) who experienced an incident stroke during a 12-year follow-up period were propensity-score matched with 4249 stroke-free individuals.

Every 2 years in the study, participants reported past-week depressive symptoms using the 8-item version of the widely used Center for Epidemiologic Studies Depression Scale (CES-D 8), in which higher scores on a 0- to 8-point scale indicate more depressive symptoms. For this study, a CES-D 8 score of at least 3 was used to indicate probable depression.

Starting about 2 years before stroke onset, the severity of depressive symptoms increased by an average of 0.33 points (P < .001), with a further increase of 0.23 points after stroke (P < .001). Depressive symptoms remained elevated for 10 years after stroke.

In contrast, the group reports, depressive symptoms remained relatively stable over time in stroke-free individuals.

There was no statistically significant difference in prevalence of probable depression at the 2-year prestroke assessment among persons with and without stroke (29% vs 24%). At the time of stroke, however, probable depression was significantly more common in the stroke group (34% vs 24%; P < .001), a difference that persisted at the 6-year assessment.

Blöchl cautioned that rising symptoms of depression before stroke are mostly subtle and might not always be clinically detectable, and it remains unclear whether such prestroke changes can be used to predict who will have a stroke, "[but even slight increases in depressive symptoms, especially mood and fatigue-related symptoms, may be a signal a stroke that is about to occur."

The clinical implications of the current findings remain unclear, she noted.

"It could be envisioned that stroke might be predicted from prestroke symptoms -- depressive, cognitive, physical -- in combination with classical vascular risk factors, but that requires further research," Blöchl told Medscape Medical News.

"Depression has long been known to follow a stroke, especially in the early months of a brain attack," Shaheen E. Lakhan, MD, PhD, a neurologist and researcher from Boston, who wasn't involved in the analysis, told Medscape Medical News. 

"Newer lines of research are now showing depression itself as a risk factor for stroke," and the current study is consistent with that, he added.

Lakhan noted cited a few caveats to the analysis, however. The subjects were assessed only every 2 years "and with a depression screening tool, not diagnostic assessment," limiting our ability to draw strong conclusions.

Nonetheless, Lakhan said, the data "underscore the importance of early recognition and management of depression especially as we age."

Blöchl, Nestler, and Lakhan report no relevant disclosures.

Neurology. Published online July 13, 2022.^[1]

Clinical Implications

• Incident stroke is associated with long-term increases in depressive symptoms, a small part of which occurs in the years before stroke, perhaps reflecting the incipient pathological process.
• Particular attention should be paid to depressive symptoms in the long-term care of patients and especially to fatigue-related symptoms.
• Implications for the Healthcare Team: Patients with stroke are at risk for persistent increase in mood disturbances. The healthcare team should be aware that this may hinder recovery and rehabilitation and should be monitored in the long term.

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