The risk of having a stroke in the middle-aged and older adults is double if the person feels cynical and hostile toward others, a study out on Thursday revealed.
The research in Stroke, a journal of the American Heart Association, also found that depression and high stress increased stroke risk.
For the study, more than 6,700 adults aged 45 to 84 answered questionnaires about their state of mind and behavior.
These surveys assessed chronic stress, depressive symptoms, anger and hostility over two years, and low scores indicated a lesser frequency of these feelings.
Subjects reported no heart disease at the beginning of the study.
They were followed for between eight and 11 years, during which time 147 had strokes and 48 transient ischemic attack (TIAs), a temporary blockage of blood flow to the brain.
Researchers found that those with the highest hostility scores -- measured by assessing a person's cynical expectations of other people's motives -- were more than twice as likely to have a stroke or TIA, compared to the lowest scorers.
Similarly, high scores on depressive symptoms meant an 86 percent higher risk, and the chronically stressed faced a 59 percent higher risk of stroke or TIA.
Perhaps surprisingly, anger was not associated with any risk of increased stroke.
The study included a broad mix of Caucasian, African-American, Hispanic and Asian people.
The associations between psychology and stroke remained even after researchers accounted for age, race, sex, health behaviors and other known risk factors of stroke.
"There's such a focus on traditional risk factors -- cholesterol levels, blood pressure, smoking and so forth -- and those are all very important, but studies like this one show that psychological characteristics are equally important," said lead author Susan Everson-Rose, associate professor of medicine at the University of Minnesota in Minneapolis.
"Given our aging population, it's important to consider these other factors that might play a role in disease risk."