Forget the “Be happy” part for now: Just don’t worry. Researchers from the University of Pittsburgh and Harvard University recently published a study that found moderate increases in anxiety resulted in even greater jumps in a person’s risk for future stroke.

As part of the first National Health and Nutrition Examination Survey (NHANES I), a comprehensive 22-year study that included 6,019 subjects, between the ages of 25-74, the team of researchers studied 419 stroke cases and looked at what portion of those victims had ever suffered from anxiety. They added to their analysis robust mental health questionnaires, blood tests, and in-depth medical examinations in order to paint a full picture of each subject’s health. In the end, the people in the top tier of anxiety symptoms were 33 percent more likely to suffer stroke later in life.

"Everyone has some anxiety now and then,” study leader and cardiovascular behavioral medicine researcher at the University of Pittsburgh School of Medicine, Dr. Maya Lambiase, said in a statement. “But when it's elevated and/or chronic, it may have an effect on your vasculature years down the road.”

Anxiety disorders represent more than the occasional case of the butterflies. They include generalized anxiety disorder, obsessive-compulsive disorder, panic disorder, post-traumatic stress disorder, and social anxiety disorder. Approximately 40 million Americans suffer from one of these big five, although countless cases remain undiagnosed — the constant panic or worry that gets brushed off as a personality flaw, rather than neurological disorder.

Often, anxiety brings with it a host of related side-effects, which themselves can do serious damage to a person’s physical and mental health. For instance, those with anxiety are far more likely to suffer from high blood pressure and increased levels of certain stress hormones. Anxiety sufferers are also more likely to smoke and be physically inactive, which the present researchers say may underlie the stroke-anxiety relationship.

While anxiety differs from depression in many respects — e.g., hopelessness and indifference vs. constant fear and panic — Lambiase and her colleague’s study echoes prior research that found depression, anxiety, and problems sleeping were all connected to an increased stroke risk.

Together, the psychological distress exerted by these disorders can make for a 29 percent greater risk of stroke. One study, published in the Canadian Medical Association Journal, found that over an eight-year period 2,367 people died of cardiovascular disease, 1,010 died particularly from ischemic heart disease, 562 died from stroke, and 795 died from another heart-related reason even though none had had cardiovascular disease at the outset. However, 14 percent did have severe psychological distress. In another study published earlier this year, older adults were found to be at a greater risk for stroke following similar distress.

So what contributes to this increased risk? First, consider the two types of strokes. Smoking and physical inactivity are the most common causes of ischemic stroke, which constitutes roughly 80 percent of all strokes. Then there are hemorrhagic strokes representing the other 20. Ischemic strokes result from a blocked vessel or artery leading to the brain. Hemorrhagic strokes are marked by burst blood vessels that bleed into the brain.

Poor diet and lack of exercise keep the body from getting rid of fat in the blood, making it more difficult for the blood to flow freely. These often result in ischemic strokes. Meanwhile, anxiety and other psychological burdens work on a hormonal level through stress.

Essentially, the brain is under an increasingly heavy load as the positive feedback loop of anxiety reinforces the disorder. This puts undue stress on the brain and makes cognitive function much harder. Neurons miscommunicate. Processes break down. It’s for this overarching reason that depression sufferers and anxiety patients face similar risk for strokes, despite their disorders varying significantly.

"Regardless of the mechanism, recognizing that depressed individuals may be at a higher risk of stroke may help the physician focus on not only treating the depression,” Dr. An Pan, of the Harvard School of Public Health, told the BBC, “but treating stroke risk factors such as hypertension, diabetes, and elevated cholesterol, as well as addressing lifestyle behaviors such as smoking and exercise."

 

Source: Lambiase M, Kubzansky L, Thurston R. A prospective study of anxiety and incident stroke. Stroke. 2013.