The proportion of stroke survivors who contemplated suicide was striking, compared with patients with other health conditions, said Amytis Towfighi, M.D., lead author of the study and an assistant professor of Clinical Neurology at the University of Southern California in Los Angeles and chair of the Department of Neurology at Rancho Los Amigos National Rehabilitation Center.

In a nationally representative sample of the U.S. population, 7.8 percent of stroke survivors reported suicidal thoughts, compared to 6.2 percent of heart attack survivors, 5.2 percent of diabetes patients and 4.1 percent of cancer patients.

"Given the high prevalence of suicidal thoughts among stroke survivors, perhaps regular screening for suicidal ideation, in addition to depression, is warranted," Towfighi said.

About 7 million U.S. adults have a history of stroke, according to American Stroke Association statistics. About one third of stroke survivors develop depression, but there is little data on suicidal thoughts, Towfighi said.

Researchers investigated how many stroke survivors had recent suicidal thoughts, as well as the characteristics of these patients using data from the National Health and Nutrition Examination Surveys (NHANES) conducted from 2005 to 2010. During that time, an estimated 6.2 million U.S. adults were stroke survivors.

NHANES is an ongoing series of elaborate, cross-sectional surveys providing a snapshot of Americans' health. This study focused on participants' responses to the following question: "Over the past two weeks, how often have you been bothered by thoughts that you would be better off dead, or of hurting yourself in some way?"

Stroke survivors were more likely to have suicidal thoughts if they had a higher depression score, were younger, had higher body mass index, lower education level, lower poverty index, were single and were women.

Among the stroke survivors, 17 percent suffered from depression. Depression is the most common psychological complication after stroke. "Post-stroke depression can be associated with poorer functional outcomes, worse quality of life, higher mortality, low psychological well-being, suicidal ideation and suicide," Towfighi said.

The researchers haven't calculated what percentage of all NHANES participants, stroke survivors or not, might be suicidal. But Towfighi cited previous studies which found an annual suicide rate that was nearly double the expected figure for the population as a whole.

The cross-sectional design of the study didn't allow researchers to determine cause-and-effect relationships between stroke and suicidal thoughts. Additionally, the NHANES data didn't include information about how recently people's strokes had occurred, or whether the strokes were due to a ruptured blood vessel (hemorrhagic stroke) or a blocked blood vessel in the brain (ischemic stroke). The study also didn't account for patients' varying levels of disability.